For those living in the European countries, PL premium can be difficult to optain. Sika makes Sikabond T2 which by far is the best alternative. a splice with 30mm overlap, or 50mm will take 140 psi / 10bar without leaks, if done like this. no outer reinforcing sleeve needed, just glassfiber tape lengthwise about 100mm , and electrical tape around. cheers! ☺
Just came across this video because a video from Tom Stanton on making a airplane powered by air. One of the comments in there pointed to this video for a possible air container. good finding =)
Played with this method recently and found that rubbing alcohol also works to clean up PL premium. Maybe a little nicer to work with than mineral spirits. I could never stand the smell.
If you do it carefully, the joint will be stronger than the bottles. The 2l bottles usually start to swell and get all distorted at about 150PSI-160PSI. Smaller bottles like 1l or 500ml can hold more pressure because the smaller diameter of the bottles. We have had these joints hold up to 200PSI on the smaller bottles before the small bottles start to distort and fail. A pressure test is featured in this video: th-cam.com/video/rLhkak4YCak/w-d-xo.html
In defense of two part epoxy: I'm certain we can find a two part epoxy that is "stronger" than PL premium. Published shear strength of two-part epoxy can be four times the shear strength of PL premium. A good bond isn't just about shear strength. There needs to be ductility (stretchiness) as well. Thickness and materials of adherends must be considered. Though I'm sure there are two part epoxies available (example Hysol EA9394 Aero - expensive) which would make a stronger thin-plastic-to-thin-plastic joint than PL premium, PL premium is strong enough for your application (the bottle broke in the test), so it's good enough, and cheap. But, if you move to stronger aerospace materials, you would want stronger aerospace adhesives.
Exactly right. There are inexpensive epoxies that will adhere better to PET plastic, but they can be very brittle and don't hold up well to the stress encountered in the bottle joint. The glue must resist peeling, as well as shearing forces, plus the fact that the bottles swell considerably in in two dimensions as they expand when pressurized. If there is an adhesive that is better for this we would love to test it. I have tried some 2-part structural adhesives ($$$) made for low surface energy plastics, and the adhesives caused the thin bottles to weaken around the joint, so they would rip open with very little pressure applied.
@@USWaterRockets Have you got a shear stress-strain curve for PL Premium? I think that's the best comparison of adhesives, barring side by side testing of lap shear specimens of the same PET material and thickness. The loading is interesting for this joint. The hoop pressure loads, typically twice the axial line loads, are carried by both layers of bottle, and the adhesive is sort of along for the ride, just has to strain with the PET radially and circumferentially. Axial loads (tension from pressure, compression from rocket acceleration, and rocket body bending) are carried through the lap splice bond like a single lap shear specimen, which will have some peel as it tilts under load. The bonded area is probably the strongest part of the structure.
The compressed air also presents a problem, as any defect in the joint will get penetrated by the compressed air and this puts stress on the joint from inside, especially as the pressure rapidly drops when the rocket is launched. It also seems that repeated launches will eventually damage even the best joint to some extent, probably from fatigue as the bottles expand and contract each time. You make some interesting points. Alas, I don't have a stress-strain curve for PL, but I will try and see if there is one available on their website.
It seems like there was a phase in aerospace adhesive development where people thought higher shear strength must mean higher bond load carrying capability. But, you can't give up strain capability for strength. You need a balance of strength and ductility. Another approach is to taper the adherend ends (by machining in metal or dropping plies in composites), but that's usually difficult and expensive. You can also reverse taper the adherend(s), so the end of the bond gets thicker at the end, and can shear strain more without letting go, preventing peel, also usually expensive.
This isn't as crazy as you think because of the way these bottles shrink when heated. By dipping them in boiling water at the right rate, you can make any sort of taper you want.
As you already know, we already made these type of splices, and they worked great. The weight difference from the slip joint and the ASymmetric splice is awesome! Great work!
I'm wondering if acetone wipe, then wipe off in one direction with dry cloth might be a better surface preparation than sanding. Adhesive bonds are chemical, not mechanical, bonds. The surfaces must be free of oil or any other contaminant, to avoid weak layers in the bond. I'm not sure the surface needs to be rough as much as it needs to be clean. I know in aerospace bonding, sanding is seen as more operator-dependent than acetone wipe, because different people will sand differently. I also think it's recommended you solvent clean after sanding. But whatever works, I guess.
The bonding of bottles is less scientifically determined and more empirically determined. Basically hundreds of people tried various things and then wrote online the results of their efforts. Eventually the best techniques were seen from the data collected over many years and then we looked at all of the best techniques with the goal of making the process easier, faster, and more aesthetically pleasing. You will find if you test this that the added surface area created by sanding creates a stronger joint and the surface roughness does add a mechanical strength to the joint that improves the strength of the chemical bond.
@@USWaterRockets I'm pretty sure aerospace adhesive bonds require solvent wipe of adherends. otherwise how do you know it's not got some traces of oil or some other greasy stuff around the shop?
I tried this with JB weld epoxy for thermoplastics and my rocket exploded at 70 psi. A rocket made of one 2 liter bottle without any splicing was able to handle 110 psi and worked great. I want to make a larger rocket now. Is there a disadvantage to using 2 part epoxy instead of construction adhesive for this splicing method or do you think maybe I just need to be more precise in fitting the bottles together?
I know this is 3 years late lol, but were you using a 5 min epoxy or a 24 hour one? The latter has a much higher tendency of creating strong & pressure resistant bonds compared to the prior.
+Michael Frymus for most bottles there is a flat or multiple lobe shape on the bottom that is called the "Foot" or "claw", which allows the bottle to stand upright. The shape of this part of the bottle is not the optimum shape for a pressure container, so when you put a lot of pressure in the bottle, the bottom will almost always burst before the sides or the top, which are a nice rounded shape that will hold pressure with less stress. If you splice a rocket with all "top" parts, it will hold pressure better than one with a "bottom" on it.
I imagine Kranthi Akhil must have had a heart attack after typing USWaterRockets, and then his forehead came down on the Enter key. Surely no one could be that rude to leave someone hanging for so long
Bond strength is very dependent on bondline thickness. Have you ever tried controlling the bond thickness with glass beads or skrim cloth? Is there anything controlling bondline thickness? PL Premium is meant mainly for dimensional lumber and plywood, which is uneven enough to retain adhesive. The bond pressure in this joint can't be very high, so it's probably the viscosity of the adhesive that prevents too thin of bondlines.
Hi there. The biggest problem with using hot glue in place of PL Premium is that it cools off too fast so you can never keep it hot when spreading it over the joint. When you go to slide the bottles together, the glue is getting cold and hardening. If you put a ton of glue on so that it stays hot longer, the hot glue begins to cause the bottles to shrink where the glue is applied, so the joint is no longer snug. Also, we have not discovered a brand of hut glue that sticks well to the PET plastic that soft drink bottles are made from. We have tried to use various hot melt glues to glue fins on in the past, and after a few launches, the glue just peels off the bottles, so it is doubtful it would make a good splice if you had a way to get it into the joint in the first place. Some people have had success using "Gorilla Glue" (and similar PolyUrethane glues from Elmer's and others), but you have to make the overlap area of the splice bigger to get the same strength as PL Premium.
It's safe to do that, but tape on tape only helps the bottom layer from tearing, not sticking and also the bottles fail before the (construction quality glue) and tape fail. However if you dont have the super strong glue then putting strips of tape top - to - bottom (bottle standing up) could help.
Hello, thanks for the great video. However we have a few questions. We've tried your method twice and the first time we didn't use the proper glue and so the second time we bought PL premium but when we put the bottle in hot water it is not shrinking it just makes the ends jagged. If you could please respond we would greatly appreciate it or give us your email so we can talk more in depth about this problem.
Your problem with the bottles sounds like you are possibly using too much heat or leaving the bottle in too long. If your water is hotter than called out in the tutorial, it will rapidly shrink the bottle a lot and it will get wrinkled like a potato chip in fryer. The trick is to get the water to the right temperature and even then you only put the bottle in the water for a couple of seconds. If the water is hotter than specified you might only have to dip it in and pull it out and it will shrink in a fraction of a second. Some people start out at a low temperature and raise it slowly until they find the bottle shrinking point setting for their stove or heater and then they use the same setting each time. You really ONLY need to shrink the bottles a TINY bit. Just enough to get the one inside the other snugly. If the fit is not snug, the air space fills with glue and that is not as strong as when the two bottles are making contact with one another. It would actually be best to talk in the comments here so that people who have the same issue they you have will find the answer out in the open. Good luck!
+Matthew O'sullivan What do you mean when you mention a fairing? Are you talking about a tornado tube coupler with an aerodynamic cover to smooth the joint, or something else?
It would work. Just be aware that when you have a 6-foot long tube made from bottles that you are careful when handling it. If you have it oriented horizontally, the weight will try and make the tube bend where you are holding it, so you should try and keep it vertically oriented so it stays straight.
Say I have a two liter bottle with 700-800 milliliters of water at about 40psi. If I increase the size to 4 liters while having the same amount of water and pressure, would I increase or decrease the performance?
+BlueLightning Films The performance will probably increase very slightly, due to the fact that the extra air volume will add thrust the original size bottles did not have. The real advantage comes when you increase the water fill to use the extra volume. Then you get much more obvious gains in performance.
There's no limit to the number of bottles you can splice together. As big as you can go and still be able to handle and transport the rocket is the limit.
+EilyssaLpsTV It takes about 24 hours to set up enough to use, but if you plan on pushing the pressure to the limit where the bottles start to stretch and deform, then you should wait a few more days. You can accelerate the curing process by putting the rocket someplace where there is a lot of humidity, or put a damp paper towel inside. This glue hardens by reacting with water in the air.
im do a project at i only can use carbonated water bottles and I also have to fight air resistance!! what Im asking is what kind of bottle I can ues?? and what can help the rocket stay longer in the air!!!!!
Can I use hot glue for the seal instead it's for a school project and the upper end of the pressure range is 80 psi I realize it won't be as strong but hot glue is all I have
+Paul Dunbar I've never tried hot glue, since PL premium is so inexpensive and works so well. I've always had problems with hot glue because I work slowly and carefully and it always seems to cool off and harden before I can mate my parts together. I'm not good at working really quickly, but I'm sure other people are faster than me.
Напрасная работа.проще усилить корпус бутылки. Двойной корпус выдерживает давление до 12 атмосфера. В бытылку 0.5 литра налить 300мл.воды и такая ракета летит лучше вашей сборной из 10 бутылок. Удачи.
The tips shrink if the temperature is too high or the bottom of the pan is super hot and you touch the bottle to it. You want to very slowly increase the water temperature and you will find the point where the plastic just shrinks very slowly. The slower it shrinks the better for you, if you can find the sweet spot. Slower shrinking means you can very gradually shrink the bottles until you get a perfect fit. If they shrink rapidly, it's easy to shrink them too much.
I don't think it is possible, because of the hardness of the glue. The issue becomes apparent if you watch video of water rockets filling with air. The bottles get longer and fatter as they stretch out. The epoxy does not stretch because it is so hard, and this causes it to rip the bottle plastic at the joint, making it fail. The only way to stop that is to epoxy and fiberglass the whole bottle to keep it from expanding.
+USWaterRockets Actually some epoxy brands stretch a little... and I have used epoxy splices to 100 psi (check out my Straton V video)... So I am sure they work, but they have a lower burst pressure. (150psi at best)
Nothing else has been discovered other than PL Premium Construction Adhesive that works. It has the best adhesion and elasticity for PET bottles. Other adhesives are too brittle, too soft, or simply do not adhere to bottles.
We never bothered with CO2 for a couple of reasons:1) To rapidly phase change from liquid to gas, CO2 needs a heat source. Without heat the transition is relatively slow and with these rockets you need all the power in a very quick burst. 2) CO2 changes state from gas to liquid at around 800PSI, meaning the most pressure that it can produce is 800PSI, which is high for a rocket made from bottles, but our world record competition rockets were made from carbon fiber and 800PSI would be considered a low pressure for one of these rockets. Air can be compressed to over 3000PSI before it turns liquid.3) Since our high pressure rockets were designed for competing for the world record, we had to follow the rules for the competition which say that only water and air are allowed for propulsion. Our non high pressure rockets aren't for competing, but CO2 at 800PSI would be too high for them anyhow.Maybe there is a way to make it work in a rocket that we don't know about, but that's our understanding of CO2 as a propellant.
+Matthew O'sullivan A 10 liter rocket will accelerate very slowly with a gardena nozzle and it will not go as high. It will probably tip to one side before it accelerates enough for the fins to hold it stable.
jordan badon In general, at any fixed wall thickness (the thickness of the plastic that makes up the pressure container) the smaller you can make the diameter of the pressure container the higher pressure to be held without bursting can be. In other words, bottles with small diameters will hold more pressure than big diameter bottles if the plastic is the same thickness. That same rule applies to splices. If the bottles are skinny, the splices will be able to withstand more pressure before coming apart. The difference in pressure is really the only thing the size of the bottle will change. Does that answer your question?
We devised this method several years ago, but did not have a chance to do comparison testing until the summer of 2012. We didn't want to publish anything without hard evidence it was at least as good as the previous methods. Glad to hear you have had similar good fortune.
I can't find PL Premium nor Sika in Vietnam , what is the third alternative glue should I use? We usually use epoxy here put that doesn't work much for me because it is hard to find a suitable epoxy ! ( I'm wondering about using heat )
I would really like to help you, but I don't know what is available to you locally. I really hope that someone from your area will read this and be able to offer suggestions. If someone knows what else to use, please let us know, and I will make sure to mention it going forward.
SMinMaster Kim I'm going to recommend you do a splice experiment with the glue you are hoping to use and inflating the spliced bottles (from a distance) until it fails. Then you will know the safe pressure you can use. We use a lot more pressure than 60PSI, so we really have not tested any common glues to see where they fail. I wish I had a better answer for you, but we never did that kind of testing.
Hi, my name is Jon Hoggard and i attend Kalkaska Public Schools in northern michigan. I am currently in astronomy, an elective offered here at Kalkaska High School and we shoot water rocket alot, but the best water rocket we have is just one 2 liter with a nose cone and wings, and its farthest flight was about 500' and i was wondering what you guys over at US WaterRockets thought was the best way to get the most distance from our 2 liter bottles? Should i splice 2 together? Should i cut both ends of the bottle and splice 3 together? How many bottles on top of that? How much weight in the front, how much water, and what preasure? How many wings? Any wings? Just looking for some advice, and looking to get any sort of feedback from you guys. Thanks, Jon.
They last as long as a regular water bottle rocket would last. Usually the bottles will get damaged from wear and tear and you have to retire the rocket, or the bottle will burst because it has a cut or deep scratch from a hard landing. We've gotten around 100 launches from these type of water rockets.
Julia Von Vanity Other Polyurethane glues have been used with some success, but we personally have not tested any others because it is commonly known that PL Premium is the best glue for the plastic that bottles are made of. There are also some industrial adhesives specifically formulated for this plastic but they literally cost 20 to 100 times as much as PL Premium and you have to special order them.
+Aggelos Simadis We use bottles that hold fizzy drinks like soda or tonic water. If the drink has fizzy bubbles then the bottle must be designed to take pressure inside. If the contents of the bottle are not fizzy, then there is a really good chance the bottle design or the plastic it is made from will explode as soon as you put a little air pressure in it.
This blew up and scared the living crap out of everyone in the closer half of my school at only 60PSI. My rocket needs pressure chambers which go up to 120PSI. Got any tips?
1) Test your bottles before you cut them. Some bottles are born with defects and they blow up at way below useful PSI.2) Make the joints as snug as possible. The more gap between the bottles that has to fill in with glue, the more chance the glue will rip apart. Shrink the inner bottle a little at a time until you can just get it to fit inside the outer bottle.3) Mark your bottles as you make them so you can put them together in the same pairs. Some bottles are a little fatter than others and so when you shrink one to fit inside, it will be snug on one bottle and loose when paired with another. Keep them together as you create them, so when it comes time to glue, they are all perfectly fitted.4) A larger overlapping area will compensate for other errors you might make. If you overlap them 30mm instead of 15mm there's more area for the glue to stick to and so the joints hold up better even if they're not perfectly mated.5) Cover the joints with packing tape with fiberglass in it, instead of duct tape. The fiberglass tape keeps the bottles from swelling at the joints, so they hold up longer. You can still put colored tap over the fiberglass tape to cover up the ugly glue color and make the rocket look neater.6) Be extra careful when sanding the joints so you don't miss any spots. The glue will not stick to the shiny smooth bottle surface. You have to get it rough for the PL to stick to.7) Mare sure that you don't have oils on the joints from your skin. Wash them well, and also you can use alcohol to wipe them off to get grease and oil off.8) Always let the glue cure for several days before putting pressure on it.9) If your climate is dry, make sure you put the rocket in a humid area like a shower room for a while because PL glue needs to be exposed to humid air to cure. Putting it in an area with steam for a few minutes will give it the humidity it needs to cure.10) Use skinny bottles if possible. 2 liter bottles are harder to work with than 1.5 liter bottles which are harder to work with than 1 liter bottles. The bigger the diameter of the bottle, the more strain there is on the joint. Good luck!
i dont know if this is just my glue or what but when i joined them i only was able to get to 5 bar and then it went bang and broken the glue i used was military grade
Hi i have a trouble. I live in Mexico and i can´t find the PL premium glue, i already looked at Home Depot and i couldn´t find it, do you know if i can use another type of glue? Thanks :D
It is a shame that there are places where you cannot obtain PL Premium. It is the only glue that we use. It is based on Polyurethane and there are many glues with this basic formulation out there, but we have not tried to find an alternative. Perhaps you can find another PU based glue locally, or even a locally sourced construction adhesive like PL Premium based on PU? Wishing you the best of luck. If you find something, we would be happy to mention it in the video if you tell us your findings.
+David Pascual Cortes I'm not sure what to tell you because every single glue we tested fails to work. Only PL Premium has been found to work in the bottle plastic. I wish I had a better answer.
+USWaterRockets Interesting. I would think any polyurethane construction adhesives would be pretty much the same, performance wise. PL is a good brand, though, maybe they have a secret ingredient...
Either one will work. They sell one called 3X and one called 8X I believe, and the resulting joint is equally strong no matter which one you use. The 8X is more "sticky" when it is fresh out of the tube, which is supposed to grip things better while it cures, so you can stick tiles to the wall with it and they will not need to be held in place while the PL cures. The wet gripping power really does not come into play with bottles, because they hold together well with no special glue.
We have tested, and many other people have tested just about every other glue you can find, and there is nothing that anyone could find that comes close to the performance of PL Premium for this application. There are glues that make a stronger bond, such as epoxy, but they are too brittle and will crack as the bottles stretch with pressure. There are CA glues (superglue) that also bond much better and are flexible, but the chemicals in the glue attack the plastic of the bottle and make it weak where the glue is in contact with it. I wish I knew of something similar to recommend, but PL is the only glue that anyone has found that can hold over 80PSI or so.
The directions on the PL Premium specifically state not to use on polyethylene...the plastic that 2 liter soda bottles are made from. Have you had any reason, other than the manufacturers directions, to not use PL Premium?
The plastic bottles we use are made from polyethylene terephthalate. Perhaps the directions are referring to one of the other forms of polyethylene? There are several, and each has unique properties. The fact that no other adhesive has yet been found that can match PL Premium for this application essentially means that regardless of what the directions say, this is the best option discovered so far.
+Russell May: I have never heard of Military Grade PL Premium adhesive. Are you using some other kind of glue other than PL Premium? If you used a different glue, then it probably is not compatible with the bottle plastic. Very few glues will stick to this kind of plastic, so chances are it's not compatible. Other causes for a joint failure are: Grease/oil from your hands in the joint. Loose fit (bottle was shrunk too much). Contact area not sanded enough.
prabhav chauhan It is only required to retire a rocket when you have launched them close to their burst pressure multiple times. You can use the rocket indefinitely if you NEVER approach the burst pressure of the spliced bottles (which you have to experimentally determine by intentionally failing some test subjects). Once you start pushing the pressure limits of a rocket, it will be weakened and will degrade over time.
It probably won't hold much pressure. There are all kinds of epoxy glues and some stick better than others, while some get very brittle when they are cured and others remain a little flexible. You have to have a glue that sticks to the bottle plastic plus it remains flexible so that the stretching bottles don't crack it. That combination of properties makes finding a suitable glue very difficult, and so far nobody has been able to find anything that works better than PL Premium.
Hi. I just spliced two bottles together using this method! Thanks but I have a question. My School launch is tomorrow, but the schools PSI is only 65. By the time I launch the rocket the glue will have been drying for around 22 hours. I can call my rocket off and wait if I want. Is it worth trying to launch it anyway? Thanks.
If you expose the PL Premium to high humidity (take it into a hot shower for a few minutes) you will accelerate the glue curing process (it is hardened by water in the air). Even if you don't do that, 22 hours is very likely long enough to hold 65PSI without failing.
I used a Polyurethane but not specifically PL Premium. (Due to lack of sourcing time. The Bostik Poly was lying around somehow) and didn't see your comment in time for the shower method. Anyhow it did end up being less than 22 hours and it did explode but at a high pressure. One half got higher than every other rocket though. XD I have since removed the glue with Isopropyl and re-glued and reinforced with tape. Next launch is Thursday do it will be able to dry for 4x the length. should be fine. Thanks for replying.
FYI, everyone who's ever tried a different glue has not had the same results as PL Premium. It seems like every other glue does not hold as well. However, I can say that most of the time the glue fails because the two halves pop apart, so anything you can do to hold the halved lengthwise should help keep the glue from pulling apart. Putting tape lengthwise on the rocket might help! Good luck!
Just had a second launch after 2 days drying time. It held and did not explode. Needless to say I was very happy. I'll keep PL Premium in the bag of thoughts until the rocket explodes. Thanks.
Sorry, but no. Super glue reacts with the bottle plastic turning it very weak, so even though it glues the plastic exceptionally well, the plastic where the glue has reacted will shatter when pressurized. Hot glue doesn't work because as you can see in the video we use heat to shrink the bottles to fit together properly, so you can imagine that applying the hot glue to the bottles will cause them to shrink and deform at the point where the glue is applied.
I have never tested PVC cement, and I don't know anyone who has ever tried. I don't think it would work at all because soda bottles are made from PET and not PVC. PVC cement is made to dissolve PVC, so it probably won't do a thing to PET plastic. It will probably just sit there until it evaporates and not stick at all.
I attempted to splice the bottles shown in the video using 2-liter bottles. I let it cure for about 60 hours, however, today when I tried to pressurize it, it EXPLODED!!!!! My next launch is tomorrow and I desperately need help!!! Any ideas?
The water is too hot, you are dipping them too long, or the bottom of the pot/pan the water is heated in is much hotter than the water is, and you are douching the bottom with the bottle and heating it from contact with the hot pan. I can't know which you are having trouble with. Remember, the idea is to shrink the bottles ever so slightly. If you shrink them so they no longer fit snug inside the other bottle, then they won't hold as much pressure. Just shrink them a tiny bit so they fit tightly. If the very bottom shrinks too much that it curls every time, you can possibly immerse them in deeper water and trim off the bottom where it curls and still have enough left that can fit jjust right.
Sorry about that. We have so many other videos showing various launcher designs and other aspects of launching that we were afraid of being repetitive. Check out our launcher design tutorials and other videos. You should see plenty of examples of what you're looking for. Thanks for the feedback. We will try to show more complete details in videos in the future.
+Matthew O'sullivan In general terms, bigger is always better for altitude or distance. The problem you have is that you have to scale up the nozzle opening diameter to keep pace with the weight increase of the added volume in the rocket. If you go past about 10 liters of volume, the mouth of a typical bottle is too narrow for the weight of the rocket, so around 10 liters is a good size limit for maximum altitude. After that you have to start increasing the pressure more than the bottles can take to go higher with a standard bottle mouth size nozzle.
Thank you! I really want to win this years highest rocket contest! Any suggestions? I have 8 bottles PL premium glue and the basic stuff so to say. Please help! :) Thank you!!
+Angel Muratalla I don't know what stores you have around where you live. Around here it is available at all the home improvement stores like Lowes and Home Depot and ACE hardware stores. I've seen it at Walmart too (not the big cartridge, but a small regular tube with a screw cap).
There are no known glues that work as well as PL Premium for splicing bottles. Many people have tried to find some substitute, and so far no better glue has been discovered. Even very expensive glues formulated specifically for bottle plastic do not work as well. You may be able to use a different glue if you are careful to keep the pressure in the bottles much lower, so they don't blow apart.
+Skyfall 555 There are a couple of things that can go wrong:1) When you shrink the inner bottle it is shrunk too much and so it fits too loose inside the other bottle. This is usually where people get caught. The fit should be very snug and hard to pull apart before you glue them.2) You didn't sand the bottles to remove the smoothness all the way around. This is important as well. Many times there is a small seam in the plastic where the bottle mold comes apart and this leaves a little uneven area that is hard to get the sandpaper into.3) The glue was not fully cured. This glue is hardened by water in the air and takes a few days to fully set up. Don't think putting them in front of a heater will make it go faster, it will blow dry air on the glue and make it take longer to set. Take them into a steamy shower for a few minutes if you live in a dry climate to get the glue setting faster.These are the main issues. A few other notes:Some people report their bottles are not very good. Test a bottle from the same supplier by inflating it and see if the bottle will hold that pressure with no splices before you use them. If the bottle alone bursts, then there's no chance the splice will make it better.Another way to make the splice artificially stronger is to make the overlapping area of the joint larger. Double the width of the overlap and double the strength.Also make sure the plastic is clean and not covered with fingerprint oil when you glue the bottles. The oil will make the glue slip off.Good luck!
prabhav chauhan We have no experience with araldite epoxy because it is not sold locally so we cannot test it, but we have read reports from various people on the Water Rocket Forum (www.waterrocketforum.com) that this epoxy does not work well for splicing.
+David Pascual Cortes The difference between the 3x and 8x only seems to be how stiff the glue is when it comes out of the tube. The 3x is a little more liquid and that makes it a little easier to spread out smoothly. If you can work with the 8x version you will get the same strength splice as the 3x glue. It depends on your personal taste which one you will prefer to use based on the thickness of the glue when it is first applied.
It depends mostly on the bottle thickness, and how well you make the joint. If you really take your time and make sure the bottles slide together perfectly and you sand the mating surfaces evenly, and you get all the oil from your fingers off the joint before you glue it, then it will be stronger than the bottle plastic. We've had some strong 1 liter bottles spliced and the joints held firm at 230PSI.
Thanks! Check out our pressure test videos. That was has some 1.5 liter spliced bottles failing at 200PSI. But by then the bottles were warping and stretched out. You'd never inflate them to that point in a real rocket. It's good to know the splices worked to that point. th-cam.com/video/rLhkak4YCak/w-d-xo.html
+Matthew O'sullivan This option will make a rocket go a lot higher than a design with tornado tubes, because those things add a lot of weight and make the rocket longer for the same volume inside. The tornado tubes can also make the air flow inside the bottle restricted, so you get less velocity, so the rocket will not go as high.
you can use a single soft drink bottle of 2 L size, make a simple launcher , and use it one the same day. splicing multiple bottles together is the next stage of water bottle rocketry. more work, more skills, more time , more effort. They wouldnt be sitting on a chair staring at a bottle for 5 days :) plenty of other stuff to do , making more rockets for example. It can be a quick hobby, basic bottle on a sunday afternoon, or it can be a life time's hobby , building bigger better faster higher rockets. as a friend once said " To infinity and beyond ! ". or in my case " over the garden fence into the field " :) hope this helps.
For those living in the European countries, PL premium can be difficult to optain. Sika makes Sikabond T2 which by far is the best alternative. a splice with 30mm overlap, or 50mm will take 140 psi / 10bar without leaks, if done like this. no outer reinforcing sleeve needed, just glassfiber tape lengthwise about 100mm , and electrical tape around. cheers! ☺
did i mention that Sikabond t2 Dries within 24-48 hours? 😉
Thanks! This is good news for people who can't get PL Premium. I'm going to pin your comment!
USWaterRockets thanks too, im honered to help, Sitting here with Ny late evening coffee (:
Is sikabond t2 still available? I've never seen it in the UK
@@Alker89 Yes it is still available. From Sika, the red/yellow brand
Just came across this video because a video from Tom Stanton on making a airplane powered by air. One of the comments in there pointed to this video for a possible air container. good finding =)
AMIGO
Same
Hi Tom 😂
Same here lol
same
Played with this method recently and found that rubbing alcohol also works to clean up PL premium. Maybe a little nicer to work with than mineral spirits. I could never stand the smell.
I would love to know what you're working on!!!!
@@USWaterRockets He's uploaded the video now. It's XL propane rockets!
I saw it! It's amazing!
If you do it carefully, the joint will be stronger than the bottles. The 2l bottles usually start to swell and get all distorted at about 150PSI-160PSI. Smaller bottles like 1l or 500ml can hold more pressure because the smaller diameter of the bottles. We have had these joints hold up to 200PSI on the smaller bottles before the small bottles start to distort and fail. A pressure test is featured in this video: th-cam.com/video/rLhkak4YCak/w-d-xo.html
Hi Tom Stanton! 😂
In defense of two part epoxy: I'm certain we can find a two part epoxy that is "stronger" than PL premium. Published shear strength of two-part epoxy can be four times the shear strength of PL premium. A good bond isn't just about shear strength. There needs to be ductility (stretchiness) as well. Thickness and materials of adherends must be considered. Though I'm sure there are two part epoxies available (example Hysol EA9394 Aero - expensive) which would make a stronger thin-plastic-to-thin-plastic joint than PL premium, PL premium is strong enough for your application (the bottle broke in the test), so it's good enough, and cheap. But, if you move to stronger aerospace materials, you would want stronger aerospace adhesives.
Exactly right. There are inexpensive epoxies that will adhere better to PET plastic, but they can be very brittle and don't hold up well to the stress encountered in the bottle joint. The glue must resist peeling, as well as shearing forces, plus the fact that the bottles swell considerably in in two dimensions as they expand when pressurized. If there is an adhesive that is better for this we would love to test it. I have tried some 2-part structural adhesives ($$$) made for low surface energy plastics, and the adhesives caused the thin bottles to weaken around the joint, so they would rip open with very little pressure applied.
@@USWaterRockets Have you got a shear stress-strain curve for PL Premium? I think that's the best comparison of adhesives, barring side by side testing of lap shear specimens of the same PET material and thickness.
The loading is interesting for this joint. The hoop pressure loads, typically twice the axial line loads, are carried by both layers of bottle, and the adhesive is sort of along for the ride, just has to strain with the PET radially and circumferentially. Axial loads (tension from pressure, compression from rocket acceleration, and rocket body bending) are carried through the lap splice bond like a single lap shear specimen, which will have some peel as it tilts under load. The bonded area is probably the strongest part of the structure.
The compressed air also presents a problem, as any defect in the joint will get penetrated by the compressed air and this puts stress on the joint from inside, especially as the pressure rapidly drops when the rocket is launched. It also seems that repeated launches will eventually damage even the best joint to some extent, probably from fatigue as the bottles expand and contract each time. You make some interesting points. Alas, I don't have a stress-strain curve for PL, but I will try and see if there is one available on their website.
It seems like there was a phase in aerospace adhesive development where people thought higher shear strength must mean higher bond load carrying capability. But, you can't give up strain capability for strength. You need a balance of strength and ductility.
Another approach is to taper the adherend ends (by machining in metal or dropping plies in composites), but that's usually difficult and expensive. You can also reverse taper the adherend(s), so the end of the bond gets thicker at the end, and can shear strain more without letting go, preventing peel, also usually expensive.
This isn't as crazy as you think because of the way these bottles shrink when heated. By dipping them in boiling water at the right rate, you can make any sort of taper you want.
As you already know, we already made these type of splices, and they worked great. The weight difference from the slip joint and the ASymmetric splice is awesome! Great work!
Thanks for the positive review, Randy!
I'm wondering if acetone wipe, then wipe off in one direction with dry cloth might be a better surface preparation than sanding. Adhesive bonds are chemical, not mechanical, bonds. The surfaces must be free of oil or any other contaminant, to avoid weak layers in the bond. I'm not sure the surface needs to be rough as much as it needs to be clean. I know in aerospace bonding, sanding is seen as more operator-dependent than acetone wipe, because different people will sand differently. I also think it's recommended you solvent clean after sanding. But whatever works, I guess.
The bonding of bottles is less scientifically determined and more empirically determined. Basically hundreds of people tried various things and then wrote online the results of their efforts. Eventually the best techniques were seen from the data collected over many years and then we looked at all of the best techniques with the goal of making the process easier, faster, and more aesthetically pleasing. You will find if you test this that the added surface area created by sanding creates a stronger joint and the surface roughness does add a mechanical strength to the joint that improves the strength of the chemical bond.
@@USWaterRockets I'm pretty sure aerospace adhesive bonds require solvent wipe of adherends. otherwise how do you know it's not got some traces of oil or some other greasy stuff around the shop?
I have been very meticulous about wiping and drying the parts with alcohol before joining them.
I tried this with JB weld epoxy for thermoplastics and my rocket exploded at 70 psi. A rocket made of one 2 liter bottle without any splicing was able to handle 110 psi and worked great. I want to make a larger rocket now. Is there a disadvantage to using 2 part epoxy instead of construction adhesive for this splicing method or do you think maybe I just need to be more precise in fitting the bottles together?
I know this is 3 years late lol, but were you using a 5 min epoxy or a 24 hour one? The latter has a much higher tendency of creating strong & pressure resistant bonds compared to the prior.
I thought i could just use tape, so i tested if the bottle would go some where....
And it exploded
can i use epoxy instead of PL premium?
i am planning on reinforcing the spliced ends with fiberglass
+Michael Frymus for most bottles there is a flat or multiple lobe shape on the bottom that is called the "Foot" or "claw", which allows the bottle to stand upright. The shape of this part of the bottle is not the optimum shape for a pressure container, so when you put a lot of pressure in the bottle, the bottom will almost always burst before the sides or the top, which are a nice rounded shape that will hold pressure with less stress. If you splice a rocket with all "top" parts, it will hold pressure better than one with a "bottom" on it.
USWaterRockets
Yes?
Dang he left you hanging forever
I imagine Kranthi Akhil must have had a heart attack after typing USWaterRockets, and then his forehead came down on the Enter key. Surely no one could be that rude to leave someone hanging for so long
Bond strength is very dependent on bondline thickness. Have you ever tried controlling the bond thickness with glass beads or skrim cloth? Is there anything controlling bondline thickness? PL Premium is meant mainly for dimensional lumber and plywood, which is uneven enough to retain adhesive. The bond pressure in this joint can't be very high, so it's probably the viscosity of the adhesive that prevents too thin of bondlines.
Yah
Hi there. The biggest problem with using hot glue in place of PL Premium is that it cools off too fast so you can never keep it hot when spreading it over the joint. When you go to slide the bottles together, the glue is getting cold and hardening.
If you put a ton of glue on so that it stays hot longer, the hot glue begins to cause the bottles to shrink where the glue is applied, so the joint is no longer snug.
Also, we have not discovered a brand of hut glue that sticks well to the PET plastic that soft drink bottles are made from. We have tried to use various hot melt glues to glue fins on in the past, and after a few launches, the glue just peels off the bottles, so it is doubtful it would make a good splice if you had a way to get it into the joint in the first place.
Some people have had success using "Gorilla Glue" (and similar PolyUrethane glues from Elmer's and others), but you have to make the overlap area of the splice bigger to get the same strength as PL Premium.
Imma use this information to make a big ass bong 😂😂
I'm guessing that bong tech was a "gateway" tech that led to this tech 😂😂
Thanks for your advice! We've tried the splice and we think it's gonna work! We were wondering if it was okay to put two layers of duck tape on?
It's safe to do that, but tape on tape only helps the bottom layer from tearing, not sticking and also the bottles fail before the (construction quality glue) and tape fail.
However if you dont have the super strong glue then putting strips of tape top - to - bottom (bottle standing up) could help.
Thanks! This helped a lot. More people should subscribe to this channel.
Hello, thanks for the great video. However we have a few questions. We've tried your method twice and the first time we didn't use the proper glue and so the second time we bought PL premium but when we put the bottle in hot water it is not shrinking it just makes the ends jagged. If you could please respond we would greatly appreciate it or give us your email so we can talk more in depth about this problem.
Your problem with the bottles sounds like you are possibly using too much heat or leaving the bottle in too long. If your water is hotter than called out in the tutorial, it will rapidly shrink the bottle a lot and it will get wrinkled like a potato chip in fryer.
The trick is to get the water to the right temperature and even then you only put the bottle in the water for a couple of seconds. If the water is hotter than specified you might only have to dip it in and pull it out and it will shrink in a fraction of a second.
Some people start out at a low temperature and raise it slowly until they find the bottle shrinking point setting for their stove or heater and then they use the same setting each time.
You really ONLY need to shrink the bottles a TINY bit. Just enough to get the one inside the other snugly. If the fit is not snug, the air space fills with glue and that is not as strong as when the two bottles are making contact with one another.
It would actually be best to talk in the comments here so that people who have the same issue they you have will find the answer out in the open.
Good luck!
Hi can epoxy glue be a good substitute for the adhesive? And can it take the air pressure?
would this be the best option or would a fairing be a better option for height and stuff
+Matthew O'sullivan What do you mean when you mention a fairing? Are you talking about a tornado tube coupler with an aerodynamic cover to smooth the joint, or something else?
Would this method work if you were thinking about making a 6ft tall LED bubble column using 2L bottles?
It would work. Just be aware that when you have a 6-foot long tube made from bottles that you are careful when handling it. If you have it oriented horizontally, the weight will try and make the tube bend where you are holding it, so you should try and keep it vertically oriented so it stays straight.
Would work with two component Pattex epoxi glue?!
As you do so that water is not rocket back inward expulsion mechanism?
Do you have to have a hole in ur homemade tornado coupler if im using 3 bottles 2 of them spliced together to make the fuselage?
+River Barnwell (Total Tutorials) Yes, we drill a hole in the Tornado Tube to allow the air to move between the segments of the rocket.
Okay thanks so much
Say I have a two liter bottle with 700-800 milliliters of water at about 40psi. If I increase the size to 4 liters while having the same amount of water and pressure, would I increase or decrease the performance?
+BlueLightning Films The performance will probably increase very slightly, due to the fact that the extra air volume will add thrust the original size bottles did not have. The real advantage comes when you increase the water fill to use the extra volume. Then you get much more obvious gains in performance.
What pressure, in your experience, can a typical joint like this handle on two liter bottles?
Would you be able to connect more than 2 bottles with splicing
There's no limit to the number of bottles you can splice together. As big as you can go and still be able to handle and transport the rocket is the limit.
Yours are perfectly circular so we need some more help in understanding how to preform the splice thank you!
USWaterRockets Where can i get good tornado tubes? They leaked more then splice failures. They only have 2 threads.
Robert Hernandez Have you added a rubber washer to the tornado tube? The ones they sell online do not come with a washer and they leak a lot.
USWaterRockets wow thanks so much!! They work so much better now with the washers.
Does this glue really take 5 DAYS to dry? Or is that what you suggest before using it? Please answer soon!
+EilyssaLpsTV It takes about 24 hours to set up enough to use, but if you plan on pushing the pressure to the limit where the bottles start to stretch and deform, then you should wait a few more days. You can accelerate the curing process by putting the rocket someplace where there is a lot of humidity, or put a damp paper towel inside. This glue hardens by reacting with water in the air.
im do a project at i only can use carbonated water bottles and I also have to fight air resistance!! what Im asking is what kind of bottle I can ues?? and what can help the rocket stay longer in the air!!!!!
Can I use hot glue for the seal instead it's for a school project and the upper end of the pressure range is 80 psi I realize it won't be as strong but hot glue is all I have
+Paul Dunbar I've never tried hot glue, since PL premium is so inexpensive and works so well. I've always had problems with hot glue because I work slowly and carefully and it always seems to cool off and harden before I can mate my parts together. I'm not good at working really quickly, but I'm sure other people are faster than me.
Напрасная работа.проще усилить корпус бутылки. Двойной корпус выдерживает давление до 12 атмосфера. В бытылку 0.5 литра налить 300мл.воды и такая ракета летит лучше вашей сборной из 10 бутылок. Удачи.
What about vaseline to make it air tight and then just use duct tape for the bond
Right? It seems like vaseline and duck tape should work for just about any given situation.
It seems like when I dip the bottle into the water, only the tips shrink. Am I using too high of a temperature?
The tips shrink if the temperature is too high or the bottom of the pan is super hot and you touch the bottle to it. You want to very slowly increase the water temperature and you will find the point where the plastic just shrinks very slowly. The slower it shrinks the better for you, if you can find the sweet spot. Slower shrinking means you can very gradually shrink the bottles until you get a perfect fit. If they shrink rapidly, it's easy to shrink them too much.
USWaterRockets Thank you. I will try not to have the temperature so high next time.
Can you develop a good splice technique for epoxy? It not as thin as PL, and it dries rock hard.
I don't think it is possible, because of the hardness of the glue. The issue becomes apparent if you watch video of water rockets filling with air. The bottles get longer and fatter as they stretch out. The epoxy does not stretch because it is so hard, and this causes it to rip the bottle plastic at the joint, making it fail. The only way to stop that is to epoxy and fiberglass the whole bottle to keep it from expanding.
+USWaterRockets Actually some epoxy brands stretch a little... and I have used epoxy splices to 100 psi (check out my Straton V video)... So I am sure they work, but they have a lower burst pressure. (150psi at best)
Can i use glass construction sealant to replace the PL premium? I can't get that kind of adhesive where I live.
Can i use a pvc sement???????????
Nothing else has been discovered other than PL Premium Construction Adhesive that works. It has the best adhesion and elasticity for PET bottles. Other adhesives are too brittle, too soft, or simply do not adhere to bottles.
did you ever try something with co2 instead of oxygen because with enough pressure it becomes liquid so the pressure can be build up way further
We never bothered with CO2 for a couple of reasons:1) To rapidly phase change from liquid to gas, CO2 needs a heat source. Without heat the transition is relatively slow and with these rockets you need all the power in a very quick burst. 2) CO2 changes state from gas to liquid at around 800PSI, meaning the most pressure that it can produce is 800PSI, which is high for a rocket made from bottles, but our world record competition rockets were made from carbon fiber and 800PSI would be considered a low pressure for one of these rockets. Air can be compressed to over 3000PSI before it turns liquid.3) Since our high pressure rockets were designed for competing for the world record, we had to follow the rules for the competition which say that only water and air are allowed for propulsion. Our non high pressure rockets aren't for competing, but CO2 at 800PSI would be too high for them anyhow.Maybe there is a way to make it work in a rocket that we don't know about, but that's our understanding of CO2 as a propellant.
What if I used a Gardena nozzle would that be big enough or to small
+Matthew O'sullivan A 10 liter rocket will accelerate very slowly with a gardena nozzle and it will not go as high. It will probably tip to one side before it accelerates enough for the fins to hold it stable.
very helpful, thanks! does it matter how big the bottle?
jordan badon In general, at any fixed wall thickness (the thickness of the plastic that makes up the pressure container) the smaller you can make the diameter of the pressure container the higher pressure to be held without bursting can be. In other words, bottles with small diameters will hold more pressure than big diameter bottles if the plastic is the same thickness.
That same rule applies to splices. If the bottles are skinny, the splices will be able to withstand more pressure before coming apart.
The difference in pressure is really the only thing the size of the bottle will change.
Does that answer your question?
Yes thanks it helps
Wow, nice tutorial!
That´s the way how we made our segments since this summer =)
Greetings =)
We devised this method several years ago, but did not have a chance to do comparison testing until the summer of 2012. We didn't want to publish anything without hard evidence it was at least as good as the previous methods. Glad to hear you have had similar good fortune.
I can't find PL Premium nor Sika in Vietnam , what is the third alternative glue should I use? We usually use epoxy here put that doesn't work much for me because it is hard to find a suitable epoxy ! ( I'm wondering about using heat )
I would really like to help you, but I don't know what is available to you locally. I really hope that someone from your area will read this and be able to offer suggestions. If someone knows what else to use, please let us know, and I will make sure to mention it going forward.
for 60 psi do we really need the pl premium?
SMinMaster Kim I'm going to recommend you do a splice experiment with the glue you are hoping to use and inflating the spliced bottles (from a distance) until it fails. Then you will know the safe pressure you can use. We use a lot more pressure than 60PSI, so we really have not tested any common glues to see where they fail. I wish I had a better answer for you, but we never did that kind of testing.
USWaterRockets thank you very much
which way is topside up , lol
Can you do this with coke bottles?
Not the bottles with the curved or decorated sides. The bottles have to have smooth and straight sides for this to work.
Hi, my name is Jon Hoggard and i attend Kalkaska Public Schools in northern michigan. I am currently in astronomy, an elective offered here at Kalkaska High School and we shoot water rocket alot, but the best water rocket we have is just one 2 liter with a nose cone and wings, and its farthest flight was about 500' and i was wondering what you guys over at US WaterRockets thought was the best way to get the most distance from our 2 liter bottles? Should i splice 2 together? Should i cut both ends of the bottle and splice 3 together? How many bottles on top of that? How much weight in the front, how much water, and what preasure? How many wings? Any wings? Just looking for some advice, and looking to get any sort of feedback from you guys. Thanks, Jon.
How many launches do they last?
They last as long as a regular water bottle rocket would last. Usually the bottles will get damaged from wear and tear and you have to retire the rocket, or the bottle will burst because it has a cut or deep scratch from a hard landing. We've gotten around 100 launches from these type of water rockets.
Can you use anything else to glue it with?
Julia Von Vanity Other Polyurethane glues have been used with some success, but we personally have not tested any others because it is commonly known that PL Premium is the best glue for the plastic that bottles are made of. There are also some industrial adhesives specifically formulated for this plastic but they literally cost 20 to 100 times as much as PL Premium and you have to special order them.
Thank you!!!
what kind of bottles u use ??
+Aggelos Simadis We use bottles that hold fizzy drinks like soda or tonic water. If the drink has fizzy bubbles then the bottle must be designed to take pressure inside. If the contents of the bottle are not fizzy, then there is a really good chance the bottle design or the plastic it is made from will explode as soon as you put a little air pressure in it.
This blew up and scared the living crap out of everyone in the closer half of my school at only 60PSI. My rocket needs pressure chambers which go up to 120PSI. Got any tips?
1) Test your bottles before you cut them. Some bottles are born with defects and they blow up at way below useful PSI.2) Make the joints as snug as possible. The more gap between the bottles that has to fill in with glue, the more chance the glue will rip apart. Shrink the inner bottle a little at a time until you can just get it to fit inside the outer bottle.3) Mark your bottles as you make them so you can put them together in the same pairs. Some bottles are a little fatter than others and so when you shrink one to fit inside, it will be snug on one bottle and loose when paired with another. Keep them together as you create them, so when it comes time to glue, they are all perfectly fitted.4) A larger overlapping area will compensate for other errors you might make. If you overlap them 30mm instead of 15mm there's more area for the glue to stick to and so the joints hold up better even if they're not perfectly mated.5) Cover the joints with packing tape with fiberglass in it, instead of duct tape. The fiberglass tape keeps the bottles from swelling at the joints, so they hold up longer. You can still put colored tap over the fiberglass tape to cover up the ugly glue color and make the rocket look neater.6) Be extra careful when sanding the joints so you don't miss any spots. The glue will not stick to the shiny smooth bottle surface. You have to get it rough for the PL to stick to.7) Mare sure that you don't have oils on the joints from your skin. Wash them well, and also you can use alcohol to wipe them off to get grease and oil off.8) Always let the glue cure for several days before putting pressure on it.9) If your climate is dry, make sure you put the rocket in a humid area like a shower room for a while because PL glue needs to be exposed to humid air to cure. Putting it in an area with steam for a few minutes will give it the humidity it needs to cure.10) Use skinny bottles if possible. 2 liter bottles are harder to work with than 1.5 liter bottles which are harder to work with than 1 liter bottles. The bigger the diameter of the bottle, the more strain there is on the joint. Good luck!
i dont know if this is just my glue or what but when i joined them i only was able to get to 5 bar and then it went bang and broken the glue i used was military grade
This bottle can withstand several atmospheres
Hi i have a trouble. I live in Mexico and i can´t find the PL premium glue, i already looked at Home Depot and i couldn´t find it, do you know if i can use another type of glue?
Thanks :D
It is a shame that there are places where you cannot obtain PL Premium. It is the only glue that we use. It is based on Polyurethane and there are many glues with this basic formulation out there, but we have not tried to find an alternative. Perhaps you can find another PU based glue locally, or even a locally sourced construction adhesive like PL Premium based on PU? Wishing you the best of luck. If you find something, we would be happy to mention it in the video if you tell us your findings.
OK thanks for answering i´ll try to look for an alternative for PL premium :D
this video saved my life! thank you so much! your channel is awesome!!!!!
Thanks for the high praise!
What? You made scuba equipment and escaped from drowning?
Hey, i have a problem. I cant import the Pl premium to mexico cause i need an a license... There is another similar glue? Please request me D:
+David Pascual Cortes I'm not sure what to tell you because every single glue we tested fails to work. Only PL Premium has been found to work in the bottle plastic. I wish I had a better answer.
+USWaterRockets Interesting. I would think any polyurethane construction adhesives would be pretty much the same, performance wise. PL is a good brand, though, maybe they have a secret ingredient...
What kind of Pl premium is it?
When i looked there was different kinds.
Either one will work. They sell one called 3X and one called 8X I believe, and the resulting joint is equally strong no matter which one you use. The 8X is more "sticky" when it is fresh out of the tube, which is supposed to grip things better while it cures, so you can stick tiles to the wall with it and they will not need to be held in place while the PL cures. The wet gripping power really does not come into play with bottles, because they hold together well with no special glue.
Thank!
Other alternative for pl premium?
We have tested, and many other people have tested just about every other glue you can find, and there is nothing that anyone could find that comes close to the performance of PL Premium for this application. There are glues that make a stronger bond, such as epoxy, but they are too brittle and will crack as the bottles stretch with pressure. There are CA glues (superglue) that also bond much better and are flexible, but the chemicals in the glue attack the plastic of the bottle and make it weak where the glue is in contact with it. I wish I knew of something similar to recommend, but PL is the only glue that anyone has found that can hold over 80PSI or so.
The directions on the PL Premium specifically state not to use on polyethylene...the plastic that 2 liter soda bottles are made from. Have you had any reason, other than the manufacturers directions, to not use PL Premium?
The plastic bottles we use are made from polyethylene terephthalate. Perhaps the directions are referring to one of the other forms of polyethylene? There are several, and each has unique properties.
The fact that no other adhesive has yet been found that can match PL Premium for this application essentially means that regardless of what the directions say, this is the best option discovered so far.
Nice job!
Thank you! Glad you liked it!
What is the name of this mass you use?
+Russell May: I have never heard of Military Grade PL Premium adhesive. Are you using some other kind of glue other than PL Premium? If you used a different glue, then it probably is not compatible with the bottle plastic. Very few glues will stick to this kind of plastic, so chances are it's not compatible. Other causes for a joint failure are:
Grease/oil from your hands in the joint.
Loose fit (bottle was shrunk too much).
Contact area not sanded enough.
is it necessary to retire a rocket after 20-25 launches, because the bottles may get weak and explode?
prabhav chauhan It is only required to retire a rocket when you have launched them close to their burst pressure multiple times. You can use the rocket indefinitely if you NEVER approach the burst pressure of the spliced bottles (which you have to experimentally determine by intentionally failing some test subjects). Once you start pushing the pressure limits of a rocket, it will be weakened and will degrade over time.
ok ,,thanks a lot,
Thank u for ur tips
hey,can i do that with just epoxy glue and duct tape instead of polyurethane glue?
It probably won't hold much pressure. There are all kinds of epoxy glues and some stick better than others, while some get very brittle when they are cured and others remain a little flexible. You have to have a glue that sticks to the bottle plastic plus it remains flexible so that the stretching bottles don't crack it. That combination of properties makes finding a suitable glue very difficult, and so far nobody has been able to find anything that works better than PL Premium.
Ok thanks, that help me a lot👍
Hi. I just spliced two bottles together using this method! Thanks but I have a question.
My School launch is tomorrow, but the schools PSI is only 65. By the time I launch the rocket the glue will have been drying for around 22 hours.
I can call my rocket off and wait if I want.
Is it worth trying to launch it anyway? Thanks.
If you expose the PL Premium to high humidity (take it into a hot shower for a few minutes) you will accelerate the glue curing process (it is hardened by water in the air). Even if you don't do that, 22 hours is very likely long enough to hold 65PSI without failing.
I used a Polyurethane but not specifically PL Premium. (Due to lack of sourcing time. The Bostik Poly was lying around somehow) and didn't see your comment in time for the shower method.
Anyhow it did end up being less than 22 hours and it did explode but at a high pressure. One half got higher than every other rocket though. XD
I have since removed the glue with Isopropyl and re-glued and reinforced with tape. Next launch is Thursday do it will be able to dry for 4x the length. should be fine. Thanks for replying.
Don't bother trying to read my comment. TH-cam's new face cut it off.
FYI, everyone who's ever tried a different glue has not had the same results as PL Premium. It seems like every other glue does not hold as well. However, I can say that most of the time the glue fails because the two halves pop apart, so anything you can do to hold the halved lengthwise should help keep the glue from pulling apart. Putting tape lengthwise on the rocket might help! Good luck!
Just had a second launch after 2 days drying time. It held and did not explode. Needless to say I was very happy. I'll keep PL Premium in the bag of thoughts until the rocket explodes. Thanks.
Can I use hot glue or super glue?
Sorry, but no. Super glue reacts with the bottle plastic turning it very weak, so even though it glues the plastic exceptionally well, the plastic where the glue has reacted will shatter when pressurized. Hot glue doesn't work because as you can see in the video we use heat to shrink the bottles to fit together properly, so you can imagine that applying the hot glue to the bottles will cause them to shrink and deform at the point where the glue is applied.
can I use PVC cement ?
I have never tested PVC cement, and I don't know anyone who has ever tried. I don't think it would work at all because soda bottles are made from PET and not PVC. PVC cement is made to dissolve PVC, so it probably won't do a thing to PET plastic. It will probably just sit there until it evaporates and not stick at all.
+USWaterRockets okay.Thank You :-)
I attempted to splice the bottles shown in the video using 2-liter bottles. I let it cure for about 60 hours, however, today when I tried to pressurize it, it EXPLODED!!!!! My next launch is tomorrow and I desperately need help!!! Any ideas?
When I dip my bottle into the water the bottoms curl up why?
The water is too hot, you are dipping them too long, or the bottom of the pot/pan the water is heated in is much hotter than the water is, and you are douching the bottom with the bottle and heating it from contact with the hot pan. I can't know which you are having trouble with. Remember, the idea is to shrink the bottles ever so slightly. If you shrink them so they no longer fit snug inside the other bottle, then they won't hold as much pressure. Just shrink them a tiny bit so they fit tightly. If the very bottom shrinks too much that it curls every time, you can possibly immerse them in deeper water and trim off the bottom where it curls and still have enough left that can fit jjust right.
USWaterRockets Ok thank you so much, I just think my water is to hot.
you didn't show how to launch it
Sorry about that. We have so many other videos showing various launcher designs and other aspects of launching that we were afraid of being repetitive. Check out our launcher design tutorials and other videos. You should see plenty of examples of what you're looking for. Thanks for the feedback. We will try to show more complete details in videos in the future.
If I made my rocket bigger than what it is would it be better
+Matthew O'sullivan In general terms, bigger is always better for altitude or distance. The problem you have is that you have to scale up the nozzle opening diameter to keep pace with the weight increase of the added volume in the rocket. If you go past about 10 liters of volume, the mouth of a typical bottle is too narrow for the weight of the rocket, so around 10 liters is a good size limit for maximum altitude. After that you have to start increasing the pressure more than the bottles can take to go higher with a standard bottle mouth size nozzle.
Thank you! I really want to win this years highest rocket contest! Any suggestions? I have 8 bottles PL premium glue and the basic stuff so to say. Please help! :) Thank you!!
where I can buy that kind of glue?
+Angel Muratalla I don't know what stores you have around where you live. Around here it is available at all the home improvement stores like Lowes and Home Depot and ACE hardware stores. I've seen it at Walmart too (not the big cartridge, but a small regular tube with a screw cap).
Are there any alternatives for what glue to use to splice the bottles together?
There are no known glues that work as well as PL Premium for splicing bottles. Many people have tried to find some substitute, and so far no better glue has been discovered. Even very expensive glues formulated specifically for bottle plastic do not work as well. You may be able to use a different glue if you are careful to keep the pressure in the bottles much lower, so they don't blow apart.
Does general epoxy work?
(At low pressures under 100 psi)
I followed all your steps and it blew up at 60 psi and it's the same glue and everything. Could you please help me with this
+Skyfall 555 There are a couple of things that can go wrong:1) When you shrink the inner bottle it is shrunk too much and so it fits too loose inside the other bottle. This is usually where people get caught. The fit should be very snug and hard to pull apart before you glue them.2) You didn't sand the bottles to remove the smoothness all the way around. This is important as well. Many times there is a small seam in the plastic where the bottle mold comes apart and this leaves a little uneven area that is hard to get the sandpaper into.3) The glue was not fully cured. This glue is hardened by water in the air and takes a few days to fully set up. Don't think putting them in front of a heater will make it go faster, it will blow dry air on the glue and make it take longer to set. Take them into a steamy shower for a few minutes if you live in a dry climate to get the glue setting faster.These are the main issues. A few other notes:Some people report their bottles are not very good. Test a bottle from the same supplier by inflating it and see if the bottle will hold that pressure with no splices before you use them. If the bottle alone bursts, then there's no chance the splice will make it better.Another way to make the splice artificially stronger is to make the overlapping area of the joint larger. Double the width of the overlap and double the strength.Also make sure the plastic is clean and not covered with fingerprint oil when you glue the bottles. The oil will make the glue slip off.Good luck!
+USWaterRockets Okay thank a lot for the tips I hope to give it another try
+USWaterRockets It worked great now my water rockets are going a lot higher thanks.
That's awesome! Thanks for getting back to us with the results!
i need tubes?
How I do the junction??
can i use araldite epoxy instead of pl premium ,,its gonna be my first spice ever ,,plz help
prabhav chauhan We have no experience with araldite epoxy because it is not sold locally so we cannot test it, but we have read reports from various people on the Water Rocket Forum (www.waterrocketforum.com) that this epoxy does not work well for splicing.
mail will have to contact them?
Hey, Pl premium advanced 8x it's okay?
+David Pascual Cortes The difference between the 3x and 8x only seems to be how stiff the glue is when it comes out of the tube. The 3x is a little more liquid and that makes it a little easier to spread out smoothly. If you can work with the 8x version you will get the same strength splice as the 3x glue. It depends on your personal taste which one you will prefer to use based on the thickness of the glue when it is first applied.
Okay, thanks, which is the failure pressure?
It depends mostly on the bottle thickness, and how well you make the joint. If you really take your time and make sure the bottles slide together perfectly and you sand the mating surfaces evenly, and you get all the oil from your fingers off the joint before you glue it, then it will be stronger than the bottle plastic. We've had some strong 1 liter bottles spliced and the joints held firm at 230PSI.
+USWaterRockets wow! thats cool, thanks, like and suscribe :)
Thanks! Check out our pressure test videos. That was has some 1.5 liter spliced bottles failing at 200PSI. But by then the bottles were warping and stretched out. You'd never inflate them to that point in a real rocket. It's good to know the splices worked to that point. th-cam.com/video/rLhkak4YCak/w-d-xo.html
Cool 👍🖖
How do u launch lol most important step and u didn't show it
tendran correo para contactarlos?
I liked the Video alot but when He brought up the Construction glue I lost It cuz Construction glue isn't sold to kids
Thanks so much
How am i suppose to launch the rocket
build a trebuchet , and ...................................................
Hello, could a hot glue gun be used in the place of the PL premium glue?? Just curious ... Thanks :D
what name bottle?
It was a while ago but I think those contained "Mountain Dew".
i call my bottle Sarah :)
Thank you for answering :D
Yvan I use hot glue instead
nice
great something that works thx
I don't have the equipment s
Yay,i tried it with epoxy glue and the whole thing blew up with just 55 psi.
Cloud Season People tried epoxy many years ago and nobody ever got it to work. The only glue anyone ever had great results with is PL Premium.
Thx for replying!!
Yes
+Matthew O'sullivan This option will make a rocket go a lot higher than a design with tornado tubes, because those things add a lot of weight and make the rocket longer for the same volume inside. The tornado tubes can also make the air flow inside the bottle restricted, so you get less velocity, so the rocket will not go as high.
I like how the newspaper has an article about NASA moon probes
Haha at 2:30 is NASA news on that paper!
Julian Petit Hahaha! We put that there on purpose! You are the first person who noticed! Good catch!
Thank you! :-)
I don't think so.
I don't know anyone who would wait 5 days to see a bottle rocket
you can use a single soft drink bottle of 2 L size, make a simple launcher , and use it one the same day. splicing multiple bottles together is the next stage of water bottle rocketry. more work, more skills, more time , more effort. They wouldnt be sitting on a chair staring at a bottle for 5 days :) plenty of other stuff to do , making more rockets for example. It can be a quick hobby, basic bottle on a sunday afternoon, or it can be a life time's hobby , building bigger better faster higher rockets. as a friend once said " To infinity and beyond ! ". or in my case " over the garden fence into the field " :) hope this helps.
SIKE! THATS DEH WRONG NUMBER