Great explaining! I got a vacuum pot, thinking to use it on my molds as well as epoxy, but had heard after the purchase that using it for epoxy was almost impossible. Glad to see I don't need to rush so much to get a pressure pot. Thank you!
All the bubbling after 3:00 is some volatile compound in the epoxy vaporizing. The gas pressure inside the chamber is not dropping any more - or else the bubbles on the spatula would increase in size. And they don't, they stay the same size. Air bubbles in the epoxy wouldn't increase in size either. So this bubbling must be some other compound evaporating. Whatever it is. Water is the most likely compound as iirc a water molecule is split off during the curing reaction of the epoxy.
You can let the epoxy cure under vacuum but there is an issue which must be addressed. Heat. Epoxy heats as it cures. In a vacuum there is no convection so conduction (with the vacuum chamber walls) is the only reasonable way for the curing epoxy to cool. If you are encasing object you will likely be using an unmodified clear epoxy. These can build up excessive heat with as little as 1/2 inch of thickness in a normal atmosphere. You may consider creating a heat sink for the mold you will use.
in theory yes. you would want to degas the epoxy before applying it to the items to be laminated together. placing the panels together should be done carefully to avoid introducing air. also in order to use the vacuum to press the panels together you would need to use a vacuum bag instead of a chamber (lots of videos on this out there). In the case of something clear (like glass) remember that most epoxy is not totally clear. Most has an amber tint to it though clear epoxies can be found.
Thanks a lot. Lots of great info and the most informative video I've seen so far. I haven't used a mixing stick yet and will try it. It seems to also prevent resin from seeping over the container its sitting in and creating a huge mess.
Excellent. I bought a vacuum pump myself for pretty much the same purposes. Also infusing finishes in wood. Your videos are great. Love the cheap DIY to make the actual chamber. These things are insanely expensive when purpose bought. Have you let the epoxy fully cure while under vacuum? I have a friend who's wanting to incase some dead insects in epoxy and I was thinking about making a mold for them and setting them up in there instead of just degassing and then pouring it.
great video mate. i have see expensive machines used to eliminate air bubbles when laminating mobile lcd screens and digitizers with epoxy and also clear laminating film. will this do the same job?? like in a basic set up if u try to laminate two pieces of glass with a epoxy or anything for example, will it eliminate air bubbles in between and act something like vaccum used to "sandwitch'' the two pieces together. i hope u got what i mean. thanks.
Hi, thanks for posting and sharing tips on how to degas resin! How are you able to keep the pump going for that long? My instruction manual says that once the needle stops moving the pump needs to be shut off. I have a 2 QT BACOENG VACCUM CHAMBER AND PUMP. It takes less the 30 seconds for the needle to get to -29 and then stops moving and I have to shut it off (stays on less then 1 minute) and there are still so much bubbles in the container. I hope you can help me.
The instructions for your pump are very strange. The increase in force on a chamber going from -29 to a perfect vacuum will be less than 3%. However the pump manufacture cautions against an implosion hazard. This seems dubious. I suspect their pump may not be capable of continuous operation (most pumps can run for hours without issue) and so they are using chamber implosion as an excuse to have you stop the pump. If it was my setup I would just let the pump run and watch it carefully to unsure it didn't overheat, which I suspect is the real issue they are trying to avoid.
I do not have any recommendations for specific machines. Your decision will be based on what you value in a machine. Fast draw down, ultimate pressure, durability, and cost are all factors. Vacuum pumps are not regulated. Their job is to generate as much vacuum as they can. For degassing applications there is no reason to limit the vacuum in the chamber and therefore no need for regulation. In other applications which involve process gasses the pressure in the chamber is normally controlled by the systems monitoring the process gasses.
it is called boiling point. This is a physical state known as pressure-temperature relationship. For example you could have gas like methane in a vacuum and under its boiling point which is -161.5 °C
Have you ever made meringue. You whip egg whites to introduce air. You continue whipping until the foam you have created has so much air that it becomes stiff, and you can pull it up into peaks. The gas you see when your mixed batch is in the vacuum chamber was not introduced by the mixing. It is already dissolved in the components. These liquids are made in large vats, dispensed into the containers, stored until sold then shipped to you. Vibrations and changes in temperature cause more air to dissolve into the liquids. To test this for yourself. Degas the components before you mix them. Mix and then degas again. It will clearly show which theory is correct. If you want to speed the process heat the components before degas them. Warming the components lowers their viscosity, and allows the gases to escape easier. If the gases are already in the components, degassing before you mix, should eliminate bubbles. If the bubbles were caused by the chemical reaction of the curing, one would expect to see the bubbles forming as soon as the components come into contact with other.
I tried degassing epoxy resin already mixed in my vac. chamber and it seemed to introduce billions of micro bubbles. But maybe my unit isn't dropping in pressure as much as yours? Not sure what the difference is.
Thanks so much for posting that excellent video. I do a lot of epoxy resin work and will definitely be building one! You mentioned you had some metered pumps for measuring epoxy. Can you tell me a bit more about those? I was thinking of rigging up a system using Peristaltic pumps but the affordable ones I've found are fairly low flow so if there's another way I'd love to hear it. Thanks!
+Boozy Christmas I use the metering pump sold by West (same company which makes this epoxy). It is slow since the pumps are operated by hand but they are cheap.
I've just did my 2nd epoxy pour, after the first time, I exhanged my 3 cfm vacuum for a 5 cfm (both are single stage)..and don't notice much difference at all. The thing barely gets up to - 28 and though it does bubble it does not do so as dramatically as yours. Now, the question as you might have guessed, is that should get another exchange for their 7 cfm 2 stage vacuum?
CFM is a rating of how fast a pump removes gas from a volume. Your problem sounds more like an ultimate vacuum issue which is how hard of a vacuum the pump can draw. A 2 stage will draw a greater ultimate vacuum than a single stage pump but 28 inches is not much of a vacuum. Before trying another pump I would check the system for leaks.
The west system clear hardener is used with the same resin as the standard hardener. The clear hardener is clearer than the normal hardener (which has a slight yellow tint).
Vacuum degassing and pressurization are independent processes. They are appropriate for different circumstances but are not mutually exclusive. Vacuum degassing is done to remove gas bubbles from the epoxy. Pressurization is done to compress and shrink gas bubbles (or possibly dissolve them). Both of these processes can be applied to epoxy in which case vacuum degassing is done first.
Hi, If you are mixing some ceramics with your two component epoxy, then how to avoid bubble introduction in to the epoxy. Can you suggest some methods? I tried degassing but I can not shake the pot like you did as its really big and bulky. also the amount I am preparing is roughly 4 ml.
If you are worried about the material overflowing the container under vacuum then you can gradually raise the vacuum over time. This will remove the air without making a mess in your chamber. Using an epoxy with a longer pot life and cure time will also help since you will have more time to remove gasses before the material hardens.
Les Wilhelm Thank you for the reply I guess I did not ask the proper question. My question is, For instance you are preparing a composite. Let say a composite with 40 wt % epoxy and 60 wt ceramic. How would you degass this? The vacuum chamber which I am using is really big and I am putting my composite inside a crucible like you did and then put the whole thing inside he vacuum chamber. I tries this with pure epoxy and it kind of worked, but not to my satisfaction.
Les Wilhelm well, the problem is, I am trying to mix ceramic powder with epoxy. as I said the weight ratio of ceramic is high. When I tried to degass the mixture, it did not 'boil' as pure epoxy does and I had bubbles all over the surface and they could not pop. When I cured this mixture, I had bubbles all through and over the samples
Jibran Khaliq It sounds like you might want to try a vacuum bag. In addition to the vacuum itself using a vacuum bag allows atmospheric pressure to compact the material as the air is removed.
Hi Les, Could you please tell me what type (brand, part number) of two part epoxy you are using? We've tried this method in a vacuum chamber after adding Lithium fluoride powder and it's too viscous, so the bubbles don't flow out like your does. I'm thinking that if we can find a very watery epoxy, it would help. Have you added any modifier powders to yours? We also have to do a similar process to the LiF powder with boron carbide powder. Thanks!!!
+Nancy Hadad What you see in the video is West Marine Epoxy, specifically #105 and #206. I have used modified epoxies before (specifically by adding marble powder) and it is difficult to degas them. While a less viscous epoxy will help the addition of solid modifiers will eventually raise the viscosity to an unusable level. If you have the equipment available you may mix your epoxy, degas it, and then add your modifiers to the epoxy and mix them in the chamber under vacuum. This requires a chamber with a port through which the mixer may pass. Other options include using a two part mold with compression, thereby gaining a greater degassing force than available from a single atmosphere degassing. Hope this helps and good luck with your project.
+Les Wilhelm TY Les! We are using the same epoxy as you now, but our epoxy never seems to get to the point of "breaking"" where it looks like it's boiling with big bubbles. All we get is a foam on top with lots of little bubbles. We left it in our vacuum chamber for over 15 minutes at almost 30 inHg. Do you know why this would be? We have about 85ml of epoxy once it is mixed, so maybe this is too much volume? Thanks for your thoughts!
+Nancy Hadad In order to degas any material the force of the expanding air must overcome the forces which prevent it from escaping. When you modify any resin you change its viscosity. When viscosity increases the force required for entrapped air to escape also increases. There are two ways to address this. First you can modify the resin to bring its viscosity back down. Solvents are normally used for these cases but selecting one which will not damage pump equipment or have negative effects on your part can be an issue. An easier solution is to increase the temperature of the resin which decreases its viscosity. This does however have detrimental effects on pot life. You can also choose a very low viscosity resin. You still have to deal with the change in viscosity brought on by your modification but having a lower starting point will help. The second is to increase the surface area you work on. The thinner the cross section the easier it will be for air to escape. This is only really applicable if you can vacuum the resin after it has been placed into its mold.
+Les Wilhelm Hello, sorry to bother you again Les. We tried reducing the volume of epoxy to a very small amount (4ml) so the surface area was very large for that amount. As I said above, we are using the same epoxy as you did in this video. We bought a new vacuum chamber with a clear top that's often used for degassing materials. In any case, we did get larger bubbles (maybe 1/4" diameter at most) and every 30 seconds or so one would grow and pop, but most just stayed on the top surface. So when we released the vacuum, we had much bigger bubbles in the material than before. Thanks for your previous help, and if you have any more thoughts on this, that would be great. We did try swirling it around in the chamber as you do in the video. The vacuum chamber suppliers suggested a few things. One was increasing and decreasing the vacuum to agitate the bubbles out. Another was to very slowly bring it up to full vacuum (increase by 10" of mercury, wait 20 seconds, and then do it again). This seems like the opposite of agitating it. The 3rd was to increase the batch size to 20ml instead of 4ml, ie they thought our batch size was too small? We have not yet tried your previous suggestion of heating up the material but that's another possibility. Also, you mentioned solvent. We have tried spraying acetone on it once it's out of the chamber which does get rid of the surface bubbles, and then more come to the surface and we can't seem to get rid of them all. Maybe we should mix some acetone into the original mixture, a small amount, and see if that works better once it's in the chamber? It's just a little baffling why ours does not do what yours does, even though our epoxy is identical.
+Nancy Hadad The difference in outcomes is caused by the difference n viscosities of what we are putting in our chambers. In this video you see an epoxy with no modification which is easy to degass. The more solid modifiers you add the harder it will be do degass. In addition to the suggestions already mentioned there are a couple more which are a bit more exotic you might try. Use an HTC (high temperature curing) resin. These resins do not cure are room temperature and will therefore give an almost unlimited amount of time for degassing. Each HTC resin will have what is essentially a baking recipe for how long and at what temperature it should be heated for it to cure. The materials you modify your epoxy with must be able to withstand this heating process. Mix the resin and modifiers under vacuum. Depending on what equipment you have available you can arrange it so you place your epoxy and all modifiers into the vacuum chamber, then apply vacuum, then mix the material. The air entrained in epoxy gets into it because it was present in the mixing cup with everything else. If you mix under a vacuum you can avoid the issue altogether. This does require something of an exotic setup as you will need some kind of mixer inside the chamber.
Hey thanks for the video! Vacuum, sooo much easier than my makeshift heat and pressure jars I was "Jerry rigging" together. I have a question about epoxy. I am using it to cast, and as a finish on certain delicate woodworking projects. If I use the epoxy on a sharp angle (meaning less than 90 degrees, using the epoxy on the large surface, with the less than 90 degree cutaway angle underneath), the epoxy is very thin at the edges. I can't tell if its just soaking up in the wood, or some sort of shrinkage is going on. It appears that the edge does have a coating on it, but as I said it is just ever so slightly pulled away.
It is a cabinet liner. The kind of cheap rubber mat you place in your cabinet drawers to prevent items from sliding around. I use it because it works and is cheap and easily available.
Hello there!, I loved your video and I have some questions. I make eyes for dolls and they must be totally clear. Bubbles on eyes makes me sell them cheaper. In this video did you mix part A and B together and then put it in the vacuum champer?. Or it is just the resin? It is posible to mix the resin and then put it in the vacuum champer, and then putting it the molds? how do you do it for the resin not to cure so fast while degassing it? How much pressure I need to make the degassing faster? The eyes I make are really tiny, 14mm-12mm so what kind of vacuum champer do I need? In my country its difficult to find them so soon Im going to buy one at ebay. Please, please, please, give me some advice. I dont want to buy something that takes so long to arrive and not know if this is gonna work for me or not! Thank you so much ♥
Both parts are mixed before I place them in the chamber. The resin I used in the video has a pot life of 1 hour. This gives me more time to work with it but also means it takes a longer time to cure. There are 2 number which are important for how well a vacuum pump works which are the CFM and ultimate vacuum. CFM is how fast the pump can move air out of your chamber. Ultimate Vacuum is how low the vacuum in the chamber can be if you left the pump running for a long period of time. A higher CFM and a lower ultimate vacuum will increase the speed at which your resin is degassed. A 2.5CFM and 75 micron pump would be plenty for your work. Also if you have a large chamber with unused space it will slow down the degas (the larger chamber has more air to move). You may also benefit from a pressure pot. This is the opposite of a vacuum chamber and is used to compress and dissolve gas bubbles in your resin. Both tools can be used in making bubble free castings. The vacuum chamber is used before the resin is placed in the mold and the pressure pot after. Pressure pots are more dangerous than vacuum chambers so be sure to do your research before trying one out. There are plenty of videos available on how they work.
all the time i was intend to make rock solid epoxy casting its become rubber. i am very much upset about the output. my cast is not being rock solid whether i want to make table top with resin or anything i want to convert it to. give me solution what should i do???
Check the documentation for the epoxy you are using. Some products are mixed based on volume while others are mixed based on mass. Be sure to follow the specified ratios carefully. Also be sure to mix thoroughly, any unreacted material will weaken the final product.
@@LesWilhelm Also check the cure time, I have some that sets up like rubber in about 2-4 hours, but turns rock solid in 3-4 days. Unless I bake it, that shortens the cure time.
You mention that you should mix the two parts epoxy before you introduce anything else. But I have been mixing epoxy and tints to color the epoxy all together and mixing it, and do not seem to have any problems. Is this what you are referring to. Not very knowledgeable of this process so appreciate the assistance.
Different manufactures have different recommendations for their products. In the end the goal is to have the 2 parts thoroughly mixed, otherwise you will have uncured resin and the full strength of the epoxy will not be realized. The epoxy I use is rather viscous and if I add significant amounts of filler it becomes even more difficult to mix, so I take care of mixing the resin first. There are other products (epoxies and otherwise) which recommend you add your fillers, colors, or other admixtures to the resin before adding the catalyst. When in doubt follow the instructions for your product. Otherwise go with whatever allows you to get a thorough mixing of the resin.
Great video. You preety much answered a lot of my question. Very informational, thanks. I do have some questions though. 1) If you are using a hour(medium/slow hardner) work time epoxy resin mix, how much less of a work tine would it be if it gets degassed for 10 minutes? Would you have 10 minutes less or half the time? Also, is there a odor once you release the pressure? Thanks again.
The time you have to work with any 2 part system starts as soon as they come into contact with each other. When determining how much pot life you actually have you must subtract your mixing and degassing time from the pot life specified by the manufacturer. Epoxies generally do not have a strong odor.
Given this is occurring at room temperature it is definitely air. The pressure in the chamber is well below atmospheric but still far too high to boil most liquids.
Les Wilhelm I'm sure the rapid expansion at the beginning is from the air expanding the but constant bubbling that continues afterwards may just be the epoxy boiling.
For hazards you should always check the MSDS for the product you are working with. Not all epoxies are the same and each manufacturer will use different modifiers.If you have never looked at an MSDS before I recommend you read the sheets for substances you are familiar with (like acetone, alcohol, or even hand soap). Sometimes people see the dangers listed in the MSDS and think the substance must be extremely toxic when in fact many common materials they use everyday have even more dire warnings. The epoxy I use is not very volatile and acute inhalation would only result in irritation. Having said that, good ventilation never hurt anyone.
If you are going to de gas such a small amount then mix the resin then fill your mould as it must be small. Simply stick the mould in your chamber then de gas your resin inside your mould. Problem solved
I have never degassed anything that large so I can't really say. That much epoxy in one container will come with its own challenges. The distance the entrained gas has to travel will be greater and thermal runaway will be more of a concern. Good luck with your project.
Great explaining! I got a vacuum pot, thinking to use it on my molds as well as epoxy, but had heard after the purchase that using it for epoxy was almost impossible. Glad to see I don't need to rush so much to get a pressure pot. Thank you!
All the bubbling after 3:00 is some volatile compound in the epoxy vaporizing. The gas pressure inside the chamber is not dropping any more - or else the bubbles on the spatula would increase in size. And they don't, they stay the same size. Air bubbles in the epoxy wouldn't increase in size either. So this bubbling must be some other compound evaporating. Whatever it is. Water is the most likely compound as iirc a water molecule is split off during the curing reaction of the epoxy.
You can let the epoxy cure under vacuum but there is an issue which must be addressed. Heat. Epoxy heats as it cures. In a vacuum there is no convection so conduction (with the vacuum chamber walls) is the only reasonable way for the curing epoxy to cool.
If you are encasing object you will likely be using an unmodified clear epoxy. These can build up excessive heat with as little as 1/2 inch of thickness in a normal atmosphere.
You may consider creating a heat sink for the mold you will use.
Awesome video sir! Thank you. I would have liked to see the gauges and valve opening as well.
Excellent video - you made it very straight forward and easy to understand. Thanks!
in theory yes. you would want to degas the epoxy before applying it to the items to be laminated together. placing the panels together should be done carefully to avoid introducing air. also in order to use the vacuum to press the panels together you would need to use a vacuum bag instead of a chamber (lots of videos on this out there).
In the case of something clear (like glass) remember that most epoxy is not totally clear. Most has an amber tint to it though clear epoxies can be found.
Thanks a lot. Lots of great info and the most informative video I've seen so far. I haven't used a mixing stick yet and will try it. It seems to also prevent resin from seeping over the container its sitting in and creating a huge mess.
Thanks Leslie Great videos on de-gassing epoxy and building the equipment.
Can you please show me your doing with the valves and the gauge. I can’t tell how to do this at all. Thanks
Excellent. I bought a vacuum pump myself for pretty much the same purposes. Also infusing finishes in wood. Your videos are great. Love the cheap DIY to make the actual chamber. These things are insanely expensive when purpose bought.
Have you let the epoxy fully cure while under vacuum? I have a friend who's wanting to incase some dead insects in epoxy and I was thinking about making a mold for them and setting them up in there instead of just degassing and then pouring it.
great video mate. i have see expensive machines used to eliminate air bubbles when laminating mobile lcd screens and digitizers with epoxy and also clear laminating film. will this do the same job?? like in a basic set up if u try to laminate two pieces of glass with a epoxy or anything for example, will it eliminate air bubbles in between and act something like vaccum used to "sandwitch'' the two pieces together. i hope u got what i mean. thanks.
Hi, thanks for posting and sharing tips on how to degas resin!
How are you able to keep the pump going for that long? My instruction manual says that once the needle stops moving the pump needs to be shut off. I have a 2 QT BACOENG VACCUM CHAMBER AND PUMP. It takes less the 30 seconds for the needle to get to -29 and then stops moving and I have to shut it off (stays on less then 1 minute) and there are still so much bubbles in the container. I hope you can help me.
The instructions for your pump are very strange. The increase in force on a chamber going from -29 to a perfect vacuum will be less than 3%. However the pump manufacture cautions against an implosion hazard. This seems dubious. I suspect their pump may not be capable of continuous operation (most pumps can run for hours without issue) and so they are using chamber implosion as an excuse to have you stop the pump. If it was my setup I would just let the pump run and watch it carefully to unsure it didn't overheat, which I suspect is the real issue they are trying to avoid.
@@LesWilhelm Do you think I should just return this pump that I got and just get a different one?
@@LesWilhelm thank you for your response!
What Vacuum pump machine do you recommend, what's the ultimate pressure and is a built in Pressure Regulator needed?
I do not have any recommendations for specific machines. Your decision will be based on what you value in a machine. Fast draw down, ultimate pressure, durability, and cost are all factors.
Vacuum pumps are not regulated. Their job is to generate as much vacuum as they can. For degassing applications there is no reason to limit the vacuum in the chamber and therefore no need for regulation.
In other applications which involve process gasses the pressure in the chamber is normally controlled by the systems monitoring the process gasses.
@@LesWilhelm Good to know that you don't need a regulator because it is quite costly, thanks~~
It's called "boiling" when the vapor pressure exceeds ambient pressure.
it is called boiling point.
This is a physical state known as pressure-temperature relationship.
For example you could have gas like methane in a vacuum and under its boiling point which is -161.5 °C
Have you ever made meringue. You whip egg whites to introduce air. You continue whipping until the foam you have created has so much air that it becomes stiff, and you can pull it up into peaks.
The gas you see when your mixed batch is in the vacuum chamber was not introduced by the mixing. It is already dissolved in the components. These liquids are made in large vats, dispensed into the containers, stored until sold then shipped to you. Vibrations and changes in temperature cause more air to dissolve into the liquids.
To test this for yourself. Degas the components before you mix them. Mix and then degas again. It will clearly show which theory is correct.
If you want to speed the process heat the components before degas them. Warming the components lowers their viscosity, and allows the gases to escape easier. If the gases are already in the components, degassing before you mix, should eliminate bubbles. If the bubbles were caused by the chemical reaction of the curing, one would expect to see the bubbles forming as soon as the components come into contact with other.
Vigorous mixing also introduces air bubbles, larger ones that are easily seen, degassing removes them.
I tried degassing epoxy resin already mixed in my vac. chamber and it seemed to introduce billions of micro bubbles. But maybe my unit isn't dropping in pressure as much as yours? Not sure what the difference is.
How much minus bars needed for degas epoxy ?
adding more bubbles ?
Thanks so much for posting that excellent video. I do a lot of epoxy resin work and will definitely be building one! You mentioned you had some metered pumps for measuring epoxy. Can you tell me a bit more about those? I was thinking of rigging up a system using Peristaltic pumps but the affordable ones I've found are fairly low flow so if there's another way I'd love to hear it.
Thanks!
+Boozy Christmas I use the metering pump sold by West (same company which makes this epoxy). It is slow since the pumps are operated by hand but they are cheap.
@@LesWilhelm Out of curiosity, would the commercial catsup and mustard pumps work?
I've just did my 2nd epoxy pour, after the first time, I exhanged my 3 cfm vacuum for a 5 cfm (both are single stage)..and don't notice much difference at all. The thing barely gets up to - 28 and though it does bubble it does not do so as dramatically as yours. Now, the question as you might have guessed, is that should get another exchange for their 7 cfm 2 stage vacuum?
CFM is a rating of how fast a pump removes gas from a volume. Your problem sounds more like an ultimate vacuum issue which is how hard of a vacuum the pump can draw. A 2 stage will draw a greater ultimate vacuum than a single stage pump but 28 inches is not much of a vacuum. Before trying another pump I would check the system for leaks.
Oh, sorry. And what about the bubbles/clear epoxy they sell. Do you recommend those epoxies. Always thought they were just cheaper, lower grade.
The west system clear hardener is used with the same resin as the standard hardener. The clear hardener is clearer than the normal hardener (which has a slight yellow tint).
I am looking at a system with a 5 gallon pot, a Pumping Rate: 5 CFM, and Ultimate Vacuum: 5 Pa, is this sufficient?
5 Pa ultimate vacuum is doable but my pump can only pull 3 CFM. You need a larger pump than the one I have.
@@LesWilhelm well, since it is a 5 CFM, it should be fine then. Thank you.
Have question. Shouldnt epoxy be pressurized in the mold? And not vacuumed?
Vacuum degassing and pressurization are independent processes. They are appropriate for different circumstances but are not mutually exclusive. Vacuum degassing is done to remove gas bubbles from the epoxy. Pressurization is done to compress and shrink gas bubbles (or possibly dissolve them). Both of these processes can be applied to epoxy in which case vacuum degassing is done first.
How do you meter the casting A & B for the right volume? Do you have a post on that?
The west system epoxy that I use has optional manual metering pumps you can get for their products. That is what I use to meter the resin.
Les I have some questions about epoxy. Is there a way I can email you?
Hi, If you are mixing some ceramics with your two component epoxy, then how to avoid bubble introduction in to the epoxy. Can you suggest some methods? I tried degassing but I can not shake the pot like you did as its really big and bulky. also the amount I am preparing is roughly 4 ml.
If you are worried about the material overflowing the container under vacuum then you can gradually raise the vacuum over time. This will remove the air without making a mess in your chamber. Using an epoxy with a longer pot life and cure time will also help since you will have more time to remove gasses before the material hardens.
Les Wilhelm Thank you for the reply
I guess I did not ask the proper question.
My question is, For instance you are preparing a composite. Let say a composite with 40 wt % epoxy and 60 wt ceramic. How would you degass this?
The vacuum chamber which I am using is really big and I am putting my composite inside a crucible like you did and then put the whole thing inside he vacuum chamber. I tries this with pure epoxy and it kind of worked, but not to my satisfaction.
Jibran Khaliq
What specifically was the problem?
Les Wilhelm well, the problem is, I am trying to mix ceramic powder with epoxy. as I said the weight ratio of ceramic is high. When I tried to degass the mixture, it did not 'boil' as pure epoxy does and I had bubbles all over the surface and they could not pop. When I cured this mixture, I had bubbles all through and over the samples
Jibran Khaliq
It sounds like you might want to try a vacuum bag. In addition to the vacuum itself using a vacuum bag allows atmospheric pressure to compact the material as the air is removed.
Hi Les, Could you please tell me what type (brand, part number) of two part epoxy you are using? We've tried this method in a vacuum chamber after adding Lithium fluoride powder and it's too viscous, so the bubbles don't flow out like your does. I'm thinking that if we can find a very watery epoxy, it would help. Have you added any modifier powders to yours? We also have to do a similar process to the LiF powder with boron carbide powder. Thanks!!!
+Nancy Hadad What you see in the video is West Marine Epoxy, specifically #105 and #206. I have used modified epoxies before (specifically by adding marble powder) and it is difficult to degas them. While a less viscous epoxy will help the addition of solid modifiers will eventually raise the viscosity to an unusable level. If you have the equipment available you may mix your epoxy, degas it, and then add your modifiers to the epoxy and mix them in the chamber under vacuum. This requires a chamber with a port through which the mixer may pass.
Other options include using a two part mold with compression, thereby gaining a greater degassing force than available from a single atmosphere degassing.
Hope this helps and good luck with your project.
+Les Wilhelm TY Les! We are using the same epoxy as you now, but our epoxy never seems to get to the point of "breaking"" where it looks like it's boiling with big bubbles. All we get is a foam on top with lots of little bubbles. We left it in our vacuum chamber for over 15 minutes at almost 30 inHg. Do you know why this would be? We have about 85ml of epoxy once it is mixed, so maybe this is too much volume? Thanks for your thoughts!
+Nancy Hadad In order to degas any material the force of the expanding air must overcome the forces which prevent it from escaping. When you modify any resin you change its viscosity. When viscosity increases the force required for entrapped air to escape also increases. There are two ways to address this.
First you can modify the resin to bring its viscosity back down. Solvents are normally used for these cases but selecting one which will not damage pump equipment or have negative effects on your part can be an issue. An easier solution is to increase the temperature of the resin which decreases its viscosity. This does however have detrimental effects on pot life. You can also choose a very low viscosity resin. You still have to deal with the change in viscosity brought on by your modification but having a lower starting point will help.
The second is to increase the surface area you work on. The thinner the cross section the easier it will be for air to escape. This is only really applicable if you can vacuum the resin after it has been placed into its mold.
+Les Wilhelm Hello, sorry to bother you again Les. We tried reducing the volume of epoxy to a very small amount (4ml) so the surface area was very large for that amount. As I said above, we are using the same epoxy as you did in this video. We bought a new vacuum chamber with a clear top that's often used for degassing materials. In any case, we did get larger bubbles (maybe 1/4" diameter at most) and every 30 seconds or so one would grow and pop, but most just stayed on the top surface. So when we released the vacuum, we had much bigger bubbles in the material than before. Thanks for your previous help, and if you have any more thoughts on this, that would be great. We did try swirling it around in the chamber as you do in the video. The vacuum chamber suppliers suggested a few things. One was increasing and decreasing the vacuum to agitate the bubbles out. Another was to very slowly bring it up to full vacuum (increase by 10" of mercury, wait 20 seconds, and then do it again). This seems like the opposite of agitating it. The 3rd was to increase the batch size to 20ml instead of 4ml, ie they thought our batch size was too small? We have not yet tried your previous suggestion of heating up the material but that's another possibility. Also, you mentioned solvent. We have tried spraying acetone on it once it's out of the chamber which does get rid of the surface bubbles, and then more come to the surface and we can't seem to get rid of them all. Maybe we should mix some acetone into the original mixture, a small amount, and see if that works better once it's in the chamber? It's just a little baffling why ours does not do what yours does, even though our epoxy is identical.
+Nancy Hadad The difference in outcomes is caused by the difference n viscosities of what we are putting in our chambers. In this video you see an epoxy with no modification which is easy to degass. The more solid modifiers you add the harder it will be do degass.
In addition to the suggestions already mentioned there are a couple more which are a bit more exotic you might try.
Use an HTC (high temperature curing) resin. These resins do not cure are room temperature and will therefore give an almost unlimited amount of time for degassing. Each HTC resin will have what is essentially a baking recipe for how long and at what temperature it should be heated for it to cure. The materials you modify your epoxy with must be able to withstand this heating process.
Mix the resin and modifiers under vacuum. Depending on what equipment you have available you can arrange it so you place your epoxy and all modifiers into the vacuum chamber, then apply vacuum, then mix the material. The air entrained in epoxy gets into it because it was present in the mixing cup with everything else. If you mix under a vacuum you can avoid the issue altogether. This does require something of an exotic setup as you will need some kind of mixer inside the chamber.
Hey thanks for the video! Vacuum, sooo much easier than my makeshift heat and pressure jars I was "Jerry rigging" together. I have a question about epoxy.
I am using it to cast, and as a finish on certain delicate woodworking projects. If I use the epoxy on a sharp angle (meaning less than 90 degrees, using the epoxy on the large surface, with the less than 90 degree cutaway angle underneath), the epoxy is very thin at the edges. I can't tell if its just soaking up in the wood, or some sort of shrinkage is going on. It appears that the edge does have a coating on it, but as I said it is just ever so slightly pulled away.
Thanks a lot Les! Your video helped me a lot in my research ;)
It's better to use a pressure pot instead of a vacuum chamber for epoxy or resin.
how to mix epoxy resin with phenolic resin
What Kind of gasket is That?
It is a cabinet liner. The kind of cheap rubber mat you place in your cabinet drawers to prevent items from sliding around. I use it because it works and is cheap and easily available.
Hello there!, I loved your video and I have some questions. I make eyes for dolls and they must be totally clear. Bubbles on eyes makes me sell them cheaper.
In this video did you mix part A and B together and then put it in the vacuum champer?. Or it is just the resin?
It is posible to mix the resin and then put it in the vacuum champer, and then putting it the molds? how do you do it for the resin not to cure so fast while degassing it?
How much pressure I need to make the degassing faster?
The eyes I make are really tiny, 14mm-12mm so what kind of vacuum champer do I need? In my country its difficult to find them so soon Im going to buy one at ebay. Please, please, please, give me some advice. I dont want to buy something that takes so long to arrive and not know if this is gonna work for me or not!
Thank you so much ♥
Both parts are mixed before I place them in the chamber. The resin I used in the video has a pot life of 1 hour. This gives me more time to work with it but also means it takes a longer time to cure.
There are 2 number which are important for how well a vacuum pump works which are the CFM and ultimate vacuum. CFM is how fast the pump can move air out of your chamber. Ultimate Vacuum is how low the vacuum in the chamber can be if you left the pump running for a long period of time. A higher CFM and a lower ultimate vacuum will increase the speed at which your resin is degassed. A 2.5CFM and 75 micron pump would be plenty for your work. Also if you have a large chamber with unused space it will slow down the degas (the larger chamber has more air to move).
You may also benefit from a pressure pot. This is the opposite of a vacuum chamber and is used to compress and dissolve gas bubbles in your resin. Both tools can be used in making bubble free castings. The vacuum chamber is used before the resin is placed in the mold and the pressure pot after. Pressure pots are more dangerous than vacuum chambers so be sure to do your research before trying one out. There are plenty of videos available on how they work.
OMG OMG Thank you so much for your advice!!!!!! I wrote everything on my notebook!.
Hello there again!, I couldn't find on ebay to buy a 2.5 CFM but do you think one of 3 CFM could work for me?. Thank you in advance!! ♥
That would be fine. All other things equal a higher CFM is better, it is just more expensive.
Oh!, okay, thank you so much!!!
Hello.I would like to know how is CFM machine .
Thanks you.
Brazil
The pump in the video is rated at 3 CFM.
all the time i was intend to make rock solid epoxy casting its become rubber. i am very much upset about the output. my cast is not being rock solid whether i want to make table top with resin or anything i want to convert it to. give me solution what should i do???
Check the documentation for the epoxy you are using. Some products are mixed based on volume while others are mixed based on mass. Be sure to follow the specified ratios carefully. Also be sure to mix thoroughly, any unreacted material will weaken the final product.
@@LesWilhelm Also check the cure time, I have some that sets up like rubber in about 2-4 hours, but turns rock solid in 3-4 days. Unless I bake it, that shortens the cure time.
You mention that you should mix the two parts epoxy before you introduce anything else. But I have been mixing epoxy and tints to color the epoxy all together and mixing it, and do not seem to have any problems. Is this what you are referring to. Not very knowledgeable of this process so appreciate the assistance.
Different manufactures have different recommendations for their products. In the end the goal is to have the 2 parts thoroughly mixed, otherwise you will have uncured resin and the full strength of the epoxy will not be realized. The epoxy I use is rather viscous and if I add significant amounts of filler it becomes even more difficult to mix, so I take care of mixing the resin first.
There are other products (epoxies and otherwise) which recommend you add your fillers, colors, or other admixtures to the resin before adding the catalyst.
When in doubt follow the instructions for your product. Otherwise go with whatever allows you to get a thorough mixing of the resin.
Great video. You preety much answered a lot of my question. Very informational, thanks. I do have some questions though. 1) If you are using a hour(medium/slow hardner) work time epoxy resin mix, how much less of a work tine would it be if it gets degassed for 10 minutes? Would you have 10 minutes less or half the time? Also, is there a odor once you release the pressure? Thanks again.
The time you have to work with any 2 part system starts as soon as they come into contact with each other. When determining how much pot life you actually have you must subtract your mixing and degassing time from the pot life specified by the manufacturer. Epoxies generally do not have a strong odor.
You need a quicker pump
Are you sure those bubbles are air or is the epoxy is boiling?
Given this is occurring at room temperature it is definitely air. The pressure in the chamber is well below atmospheric but still far too high to boil most liquids.
Les Wilhelm I'm sure the rapid expansion at the beginning is from the air expanding the but constant bubbling that continues afterwards may just be the epoxy boiling.
So wrong, Les...
If you use a vacuum storage tank you will increase your pot life.
Surely a mask required when degassing EPOXY?? as fumes can be dangerous if inhaled............
For hazards you should always check the MSDS for the product you are working with. Not all epoxies are the same and each manufacturer will use different modifiers.If you have never looked at an MSDS before I recommend you read the sheets for substances you are familiar with (like acetone, alcohol, or even hand soap). Sometimes people see the dangers listed in the MSDS and think the substance must be extremely toxic when in fact many common materials they use everyday have even more dire warnings. The epoxy I use is not very volatile and acute inhalation would only result in irritation. Having said that, good ventilation never hurt anyone.
but how to dissolve (remove) epoxy ?? any1 can help me
plz ?
Acetone has worked for me.
sick dude. thanks
Thank you ... that was helpful.
Heisenberg!
If you are going to de gas such a small amount then mix the resin then fill your mould as it must be small. Simply stick the mould in your chamber then de gas your resin inside your mould. Problem solved
𝙄 𝙬𝙖𝙣𝙩 𝙩𝙤 𝙙𝙤 4 𝙩𝙤 5 𝙜𝙖𝙡𝙡𝙤𝙣 𝙖𝙥𝙤𝙭𝙮 𝙙𝙚𝙜𝙖𝙨𝙨𝙞𝙣𝙜 𝙖𝙩 𝙤𝙣𝙚 𝙩𝙞𝙢𝙚 𝙩𝙝𝙖𝙣 𝙬𝙞𝙘𝙝 𝙘𝙛𝙢 𝙫𝙖𝙘𝙘𝙪𝙢 𝙥𝙪𝙢𝙥 𝙄 𝙣𝙚𝙚𝙙 𝙣 𝙝𝙤𝙬 𝙢𝙖𝙣𝙮 𝙩𝙞𝙢𝙚 𝙩𝙤 𝙩𝙖𝙠𝙚 𝙙𝙚𝙜𝙖𝙨𝙨𝙞𝙣𝙜
I have never degassed anything that large so I can't really say. That much epoxy in one container will come with its own challenges. The distance the entrained gas has to travel will be greater and thermal runaway will be more of a concern. Good luck with your project.
@@LesWilhelm thaks for reply
Thanks Leslie Great videos on de-gassing epoxy and building the equipment.