Amazing how 'Prototype' builds end up being the permanent solution, I'm to the point now the only prototypes that get re-built as an improved final product is because I had to build more than one! :) Love you content and I thank you for it!
Doug, Long life probably due to overdesign, It was just made from what I had at the time! I am hoping for another 30 , If only I could make it that long!!!Martin
My old Spitfire used a verry simular universal joint on the drive shaft. Only diffrence was it was spring steel flat plates. I like the use of leather. Far less danger of snapping.
Found your channel last night while looking after grandson (he's 3 and won't let me do anything technical, hitting pause every 20sec~2 minutes doesn't spoil video too much) I've always interested in anything to do with vintage/veteran engine building so watched your piston casting experiments. Anyway, real impressed with the amount of information your giving out. Never having researched aerators (or done any casting) I thought they were far more complicated but seeing that one stripped down the principle and operation becomes obvious. Thank you.
Peter, Aren't grand children fun! 😀 At least as grandparents we do have the ability when we have had enough to pass them back to Mum (Or Dad) and say "here you are". No, seriously, they are great I have 5. The trick is to get them interested in doing things - he will be out in the shed making moulds in no time - just like sand castles at the beach. I am glad that you are finding the videos interesting and above all informative. That's why I put the out there and its nice to know that I am having at least some success... Martin
@@olfoundryman8418 LOL, that's what I did with granddaughter when she was 2~3 (she's 15 now) Grandsons mother has 'issues' (bipolar) I don't get to give him back (I have 2 stepdaughters, younger one had kids early)
This video reminds me of a story I heard about the development of the Harrier jump jet. They needed to control the rotating jet nozzles on the sides of the aircraft and thought that they would probably need a fancy servo mechanism to do that but that would take time so for the prototype they went with a bicycle chain, wound around the cylindrical part of the nozzle attached to a small motor placed in a suitable place. This worked so well that the finished aircraft also had, you guessed it - bicycle chains.
Lol bud cubcadet garden teacher in the 70s had the same motor set ups like this universal joint ain't nothing wrong with it works the best has for years love your work very intelligent man and mentor thank you
Cool and innovative shop made machine, thank you. I always thought it funny that a painter's house needs paint, A plumbers house has drips, A foundry man's shop is welded together tid bits.
Burn, It is a crude and roughly constructed machine - it was just a trial with the intention of building a bigger better one if it worked but it worked so well that a better one was not necessary. There are some cast bits in it and on most of the things I have made cast parts are used. I recommend that people build a machine like this rather than or at least in addition to build a sand muller. But Yes, the electric metal glue gun is a great device 😊… Martin
Thanks for taking the time to show us this very valuable piece of equipment and how it works. It may not be a muller, but if you think about it your sand gets mulled to some extent every time you ram it into a mold.
Jack, I have always hankered after a real muller - many times been on the cusp of building one but they are a lot of work and I managed without one for many years. A friend described what he had seen at another foundry so I imaginered my aerator from what he said. It s not a muller - totally different action but it seems to substitute very well plus it leaves the sand nice and fluffy whereas a true muller leaves the sand a bit compacted, some foundries first mull the sand and then aerate it through a machine like mine for the best of both worlds. While both would be nice I value the aerator the greater and its an easy build... Martin
Thank you for your comment. For a quick roughie the machine does work remarkably well. I will be interested to see what improved variants others come up with. Martin
I had planned on Petrobond sand and finding or building a Royer for it. This looks like the ticket for green sand and possibly Petrobond too. Thanks for showing your elegant solution.
Driftless, I have to issue a note of caution here. My sand aerator does not like sticky sands - nice new green sand is so strong that it tends to clog the aerator and if it is at all on the wet side it is very hard to get it through the machine. I have never tried the machine with petrobaond sand so I do not know if the machine will handle it. I believe if the machine was 8 inch diameter instead of the 6 inch that I made it and if it had a 1 hp motor instead of the 1/2 hp it might have a better chance with the petrobaond. If someone wants to turn up here with some petrobaond I will try the machine on it because I would like to know if it will work too. But it sure works well on my sand... Martin
Larry, This type of machine was suggested to me by a friend who saw on in operation at a large foundry. I built this one "on spec" never having seen one at all, it was all a guess. But it was an easy quick build (certainly compared to a muller) and it sure works well, mixes and fluffs the sand up delightfully. The sand feels positively "silky" afterwards.. It is certainly a solution worth a try and even if you have a Muller I would use one of these machines after mulling to "decompact " the sand. I would suggest making it that 2 inches bigger than mine. Glad that you like the videos.... Martin
John, Nice to hear from you again, how is the sunny north? Trying to keep the videos coming but I seem to be very slow at doing them. How people can do one a week let alone and even one a day as some do has me beaten. Martin
JB, How is our sunny west? Damn cold over here! This machine is a lot easier a build than a muller. But a muller would be nice too, particularly if you are making up green sand from scratch and you need the mulling action to roll the clay out onto the sand grains. Also for making up silicate sands or other core type sands a Muller would be a good thing, but this machine has certainly done the job for me now for many years. Ideally If one was very serious one would have both mull first and then aerate, but maybe life is too short to build both, Martin
Thomas, The machine does work well but I thought the video rather hacked and disjointed, Cecil B DE Mille I aint! But thank you for your comment.Martin
Rupert, The machine seems to give the sand a nice silky feel and it rams all the better for having gone through the machine. All my green sand goes through this machine. I do not have a muller and because of this machine I do not need one. Mulled sand benefits from being put through such a machine after mulling... Martin
Given that you made this machine @ 30 years ago I think that it proves a couple of points; 1. KISS Principal, Keep It Simple Stupid. Straight drive, no belts to wear or go out of alignment or break. 2. Universal Joint. Not sure that it qualifies as such but it certainly qualifies as a Vibration Free Drive Coupling and I think that no matter how ugly it looks, the proof is in the pudding as this joint has removed any vibrations from reaching the motor and damaging its bearings. It also gives efficient drive and a fail safe sear point should something jamb. 3. Putting some witness marks and numbers on the various shafts and pins will make it faster to service. Question? Did you cast the aluminium ring and then machine it on your mill? A thoroughly captivating video for those of us with more than a passing interest in home casting. Mark
Mark, Have you moved yet? What happened to your visit? You are right about the witness marks but I don't really service it that often :)Yes I did cast the aluminium ring but for another purpose (to hold a cyclone for my vacuum cleaner, way ahead of Dysan) I just repurposed it with a quick bit of turning in my lathe. The video was indeed made for the more serious foundry YTers, Martin
what in the hell are you talking about "crude" my car uses the exact same device to couple my steering column to my steering gearbox, until rack and pinyon steering came about all cars used this design. its NOT crude its ELEGANT . a fantastic design easy to build, reliable, and if it should go wrong very easy and inexpensive to repair !!!!
normdoty, Yes, indeed many older cars did use that sort of universal joint in things like steering shafts. Its not the joint itself that is crude but rather my quick and dirty replication of it 😏. It is indeed elegant in its simplicity and ease of build - as uni joints go it is about the easiest to make and has good ability to tolerate considerable misalignment. Not too sure that I would want it driving the rear axle though 😀 … Martin
I'm rather a fan of using a cordless drill and one of those egg beater looking cement mixers for the casting I do. Particularly nice compared to mixing oil in by hand stirring
Silicone, Yes, I use either a cordless drill or a drill press as a first stage in mixing CO2 silicate sands but I find that it does not do all that good a job so I follow this with passing through a 1/8 inch sieve and then a final hand mix. My aerator mixer device was made only to handle green sand which it doers extremely well producing a fluffy silky feeling sand. I have never tried either a silicate or an oil bonded sand in it. I would guess that it would handle the silicate sand well as it has low green strength, but I suspect that the oil bonded material might cause it to jamb up because of the oil sands high green strength (I am talking petrobond here). Certainly, new green sand which is very strong does cause problems and I have to feed it very slowly a bigger machine say, 8 inch diameter as against 6 may well solve this problem.... Martin
Your universal joint doesn't look crude OR rude to me. I've seen similar devices on automotive steering columns and hot water heating's circulation pumps before. It's actually quite good.
Ron, Thank you for your comment. You are correct, similar joints have been around for a very long time although usually constructed with a little more finesse than mine. I guess that the proof of the pudding though is that it has lasted 30 years or so and is still going strong.... Martin
thank you for your video. I am keen to make one could you list the modifications that you would do to it if you were to revisit the design. the specifications so far are: a true 1 hp motor 1440 rpm half inch shaft (possibly 5/8 if an 8 inch body is used as there will be more torque). 8 inch body tube pvc a quarter inch thick rubber walled aerating chamber surrounding the powered rings two powered rings comprising of 6, half inch (?) bolts one fixed ring of 6, half inch bolts in between the powered ring set. one flexible universal joint bushes top and bottom with shielding to prevent sand entering the bushes. I would further suggest that there be some feed hopper to assist in the input of sand into the unit. a further question, how often do the bolts forming the powered ring wear out?? what clearances do you have between the powered bolts and the fixed ring of bolts? should the heads of the bolts be left on or cut off to bring the bolts closer? your opinion - instead of the two half rings to hold the fixed bolts would a fabricated ring forming a grate with a slot to slip in between the powered rings be a better solution???? also would you have more bolts on the bottom ring of powered bolts to reduce the spacing - courser spacing on entry , finer spacing on the final stage. thank you
Charles, You have pretty much nailed it. I would certainly go to 8 inch but it does not have to be PVC tube could be anything that size and solid enough that you can get your hands on. The rubber I use is about 1/8 inch insertion type I replace it every few years as it just hits the rotating bolts sometimes and that wears it away. Top powered ring only has 4 1/2 inch bolts , used to have more but this tended to throw the sand upwards too much and not allow it to move downward through the machine (this is more a problem when the sand is newer or a bit wet i.e. when it is stronger it sort of churns above the top powered bolts and wont go through) lower powered ring has 8 bolts 4 by 1/2 inch and 4 by 5/16 inch (again its what I had and could get to fit!)I too have thought about a hopper but foundry sand does not move well in hoppers unless they are very steep as the sands angle of rest it very high. A vibrator attached to the hopper would probably be necessary I am interested to see what you can come up with. Remember my machine was a proof of concept thing made out of stuff (junk) to hand and other than fiddling with the number of bolts I have never improved the design so improvement should be very possible. I look forward to seeing much improved designsHave never had to replace either the powered or stationary bolts/pins they have worn a bit but not anyway near to needing replacement. Sometimes they have come loose and been thrown out , I just screw them back in, trick is to get the lock nut tight.Clearance between bolts Hmm, good question at a guess about 1/4 inch. I leave the heads of the bolds on (I am lazy! :)) but the heads make it easy to fit and tighten the locknuts note the 1/2 bolts have a flat ground on one side of the head and this flat is orientated to give clearance for the stationary pins.Grate with a slot - not too sure what you mean here, PM me so I can come back to you with an email address that you can send a sketch too and I would be glad to have a look.Bottom ring does have 8 bolts upper 4 and I certainly think that is the sort of way to go, I am contemplating only two or perhaps three for the top ring as a way of improving performance with new (and therefore stronger) sand. Let me know what transpires.Martin
Marty, Go for it. You will not be disappointed at the job it does on green sand. I would recommend that in line with comments I made during the video you make it just that bit bigger and more powerful than mine i.e. 8 inch diameter and 1 hp motor. Be aware that I do not know how it will work on petrobaond - it may be that it is too sticky… Martin
John, The customer says he will bring the car around one day soon I will be out with the camera and shoot a video of it running under the bonnet and all if I get half a chance... Martin
So the pins are between the both rotor levels? Do you have a large funnel that goes on top of the inlet, or do just shovel the sand in there? Great work! I've been looking into building a muller for quite some time, if your device works fine, i might build one also. I figure it is rather unsuited for initial mixing of sand with clay or bentonite, but for clearing sand of rocks after casting rather.
rocketryi, Yes the 6 stationary pins are between the two rotor levels. No funnel as damp sand has a very steep angle of rest and it would not slide down a funnel easily. I use a scoop that has about the same diameter as the white aerator body. Remember this machine was an experimental first try - my idea was to build a bigger one if this one worked but it worked so well that a bigger one was not strictly necessary. That said if I was to build it again I would make it about 8 inch diameter and use about a 1 hp. motor. If you gave your sand an initial rough mix on the floor (sand clay water and all) with a shovel and rake for a few minutes and then passed it through the aerator perhaps a couple of times I think you would be impressed with how well it turns out. Even if you do have a muller its worth using an aerator after mulling as it fluffs the sand up nicely breaking up all the compacted lumps that mulling tends to produce. The only problem I have had with the machine is that my new sand (a natural green sand) is so strong that it clogs the machine until it (the sand) has been used a few times and thus it has got a little weaker - I suspect but do not know for sure that petrobaond sand particularly if new might clog it. I suspect that the clogging problem would go away if the machine was just that bit bigger. It is a much easier build than a muller and because of it I have never felt the need to build or use a muller....Martin
@@olfoundryman8418 Hey and thanks for your reply martin! Such a rare thing of a person producing videos on youtube being into actually replying to questions raised, even a while after the video released. Luckily i don't use petrobond, thus will see if i can mititage the clogging problem for my greensand variant. I assume a vibration motor would help solving this (or could make it worse, if the sand further compresses itself because of vibration). If all fails, some kind of rake could be attached above the rotor... i guess i can find a way. Thanks for making an in-depth video on such a simple machine!
rocketry, Clogging is only a problem with very high strength sands (in my case the new sand) I think a home made sand unlikely to be that strong ( I could be wrong of course 😊 ) Sand after a few uses presents no problem at all. I have no idea re vibration - you would just have to try it. I figure a slightly bigger 8 inch (currently 6 inch) machine would probably handle stronger sand way better, again though you would have to try it. Good luck with it all and do let us know how it goes... Martin
@@olfoundryman8418 Your reply leads to the question what the difference between homemade sand and "the new sand" is... Do you mix your sand yourself? Do you have a recipe?
rocketri, My sand is a natural sand i.e. it is straight out of the ground. It naturally has the right sized sand grains and contains some sort of natural clay probably a Kaolin type. Al I do is sieve it to remove the few larger grains and add water to the right moisture level. Sands like this were very common all around the world big deposits were in Albany NY USA for example. Mine came from a quarry about 20 miles from where I live but there once were dozens of deposits around Melbourne here in Australia. The diffewrnce between new and used is simply that sand that is used and sand which is stil as dug out of the ground. So sorry, but no, I do not have a recipe - beyond sieve it wet it and use it 😊... Martin
Hello from Norway! I am working with granite cuting wire saw and we got a lot off small granitt dusts after cuting work. Is it possible to use it and clay to form models instead sand? Best regards Darius
Darius, Hello back from Melbourne Australia. Many other materials are used as a "sand" for moulding - zircon, chromite, olivine for example but I have not heard of granite dust being used. Granite is about 20% Silica and 65% Feldspar, Feldspar is quite a refractory material and might perform ok as a moulding sand. To be honest I do not know for certain how it would go but its refractory nature would suggest that granite dusts - providing they are not just granite flour - might be worth a try. However granite contains some mica and this tends to expand a lot when it is heated and this may cause problems. If you have no other source of a suitable moulding "sand" the dust may be worth a try, so give it a go and let us know how it went.... Martin
Thanks for sharing this. I collecting the bits to build an 8" version. The 1HP motor is 1725 RPM. Do you think it will run too fast? Has anyone shared their designs with you. It would be interesting to see other peoples take on the machine design.
Dan, Sharing was my pleasure, thank you for watching. Your speed will also be the quicker for the increased diameter, in mine the tip of the rotor bars does about 2300 feet per minute however with an 8 inch diameter and 1725 RPM the tip speed will be about 3600 feet per minute, a bit more than a 50% increase. Will it matter? I honestly do not know but I doubt it. I think that at this higher speed the machine will process the sand much quicker and that's a good thing. When I built mine I had very little to go on other than a vague description from a friend who had seen one in use on just the one occasion. It was very much a matter of "suck it and see" hence my construction was quick rough and a bit small and meant only as a trial of the idea with a larger better built effort in mind if it all went well. As I think I mention in the video it went so well that I have never bothered with the better version. Only one other person who built a machine with a similar purpose some time ago has contacted me. His design is rather different and by the looks of before and after photos of the sand it does not seem to fluff it up perhaps quite as well, also I suspect it may have been a bit slower in processing the sand. So, alas, I have no other "takes" on design, You are the first that I know of to be making a similar machine to mine since I put the video out. So I guess that you too are in a bit of a "throw it together and hope situation" although perhaps with a little more to go on than I had. Hey, its a simple machine so as they say in the classics - what could possibly go wrong? :) Good luck with it, I await the results of your effort with great interest please keep me informed. I think that you will be very happy with the results, I was..... Martin
Watching this again I noticed your rotor has a mix of bolts and studs and maybe two sizes. Is there a reason for this? Still sidetracked on the lathe and master mill which mounts to it.
@ 16.24, were you a gynecologist in a previous life..? sorry, couldn't help it. Nice stuff. Yes, think I'll knock one up. Have built a muller, as you say, bit involved. Oh, and Nice, really nice.
Good lord No, I could not think of anything worse. Occasionally Ok,😏 but every day all day, no thank you! I agree with you on the muller I have almost continually contemplated building one but it is just so much work to do so and so much else to do and the older I got the less use I would get out of it. Tried to buy one but the size I wanted is quite rare and much sought after. If I had been into petrobond sand which (apparently) one just about must have a muller for I would have built one years ago. In truth once I built that aerator the need for a muller went away - for me anyway and I note that even after mulling people with an aerator pass the sand through it as it fluffs the sand up to a nice silky feel that rams well. if you build one you will love it... Martin
Just a thought.... What if... I have a concrete mixer. A simple consumer product like Baumr-AG or Kartrite machine... If I (struck through) When I try this "method" I share the results 🙂
Andrey, What you are suggesting has been tried in this video th-cam.com/video/Y0-lx95NLRs/w-d-xo.html Note that he is using it on petrobond sand but it should work with green sand too (I think!). This really acts as a sand muller NOT an aerator. Mullers tend to compact sand whereas an aerator tends to fluff it up in a nice feeling uncompacted way. If I had a muller I would use it to mix the sand properly but I would then pass the sand through an aerator like the one in my video here. However I feel that this aerator does the job of a muller as well as an aerator. Love that 5.5KW spindle 24000 rpm - wow nice. My old mill (1985 Dyna 4400 DM ) has only 4KW and just 4800 rpm. What do you use this spindle on?... Martin
Hey Martin, how often do you need to replace the bolts and what size are they? I'm building one very similar to yours, But a little smaller. Mine is just gonna be an attachment for a drill press. From the video, it looks like your top row (spinning mixer) you only have 4 and they might be 1/2". The second row looks like 4 => 1/2" and 4 => 5/16". For the outer ring I'm going to tempt fate and make it out of 4" ID steel tube.
OMM, I have never had to replace the bolts. I have had one or two come loose and need to be screwed back in. Remember there is a row of 6 stationary rods between the two rotating rows, these are 1/2". Your guess is right as to the size and number of the rotating bolts. If I had to guess I would say that you will be disappointed with a smaller machine. Mine tends to clog when the sand is new and strong and in these circumstances needs to be feed very slowly - I suspect that petrobond will also tend to clog it (never tried) as I think it is a strong sticky sand. I suggest actually building it bigger say 8 inch diameter with about a 1Hp motor as I suspect this would help with the clogging. I was always going to build mine bigger as this one was only a small trial to see if the idea worked but it handles the sand so quickly (once the sand has been used a bit) that I never bothered. Please do let me know how you get on. I will be interested to see if a 4" version will work and if so how well.... Martin
@@olfoundryman8418 Martin, I plan on doing 2 stationary rods (but again 5/16 screws) above the beater to take care of bigger chunks and eight stationary rods between the beater rods. The drill press motor is 2 hp.
Omm, 2 Hp should be way more than enough for a quite big machine! However I think that stationary bolts above any of the rotating ones may just serve to hold the sand back as foundry sand tends to "hang back" unless something (like the rotation) makes it move. Also 8 stationary rods with just 4 inch diameter does not leave much room for the sand to move through. I don't really know of course as I only ever built the one machine and never tried any variants so my suspicions /guesses etc could be way off. Please let us know how you go - do a video on it perhaps…. Martin
@@olfoundryman8418 I'm doing a full step-by-step document of it at "The Home foundry" forum. As I mentioned to you before there is quite a few good guys there. But if you just want to follow along, forums.thehomefoundry.org/index.php?threads/how-do-you-re-purpose-green-sand.1107/#post-27235
I built a similar machine years ago with a little different design on the pulverizer. How can a fella post a picture in the comments? I would send out a photo if I could.
Centaurus, I am not surprised that there are other machines out there, after all I copied one (sight unseen) that I had been told about. What does surprise me is that so far you are the only other constructor to come to light! Any other makers out there? I imagine that considerable design variation would be possible would out adversely effecting the machines function. Unfortunately I do not know how to post a picture in the comments I have never seen one so it may not be possible. I would be interested to see your design so can I suggest that you PM me and I can send you an email address that you can send a picture to. Martin
Centaurus, I am not surprised that there are other machines out there, after all I copied one (sight unseen) that I had been told about. I am perhaps a little surprised that you are (so far) the only other constructor that has come to light, any others out there? Unfortunately I do not know how to post a picture in the comments,I have never seen one so it may not be possible, pity I think! However I would very much like to see your machine so if you wish you can PM me and I will come back with an email address that you can send a picture too. Do you still have your machine, do you still use it, and have you tried it on Petrobond? Martin
Martin, I have not used it for Petrobond as I never could get past the stink of that stuff so I stuck with the clay bonded sand. I sent you a PM so if you would like I can send you some pix.
Centaurus, I have actually replied to your Pm, did so about 19 hours ago. Let me know if you did not get my reply as I can probably do a copy and paste to resend (a bit long to retype!) I did include my email address so you can send those pictures. I would very much like to see them...Martin
jack. The rotating rods break up any lumps in the sand, mix it all properly, and aerate it so it sort of fluffs up and makes it feel as close to silky as its possible for sand to feel. After passing through this machine the sand rams much better and makes a better stronger mould.....Martin
Amazing how 'Prototype' builds end up being the permanent solution, I'm to the point now the only prototypes that get re-built as an improved final product is because I had to build more than one! :) Love you content and I thank you for it!
Love the universal joint. If it worked for 30years without failing, it better than most purchased units on the market today.
Doug, Long life probably due to overdesign, It was just made from what I had at the time! I am hoping for another 30 , If only I could make it that long!!!Martin
My old Spitfire used a verry simular universal joint on the drive shaft. Only diffrence was it was spring steel flat plates. I like the use of leather. Far less danger of snapping.
Found your channel last night while looking after grandson (he's 3 and won't let me do anything technical, hitting pause every 20sec~2 minutes doesn't spoil video too much) I've always interested in anything to do with vintage/veteran engine building so watched your piston casting experiments. Anyway, real impressed with the amount of information your giving out. Never having researched aerators (or done any casting) I thought they were far more complicated but seeing that one stripped down the principle and operation becomes obvious. Thank you.
Peter, Aren't grand children fun! 😀 At least as grandparents we do have the ability when we have had enough to pass them back to Mum (Or Dad) and say "here you are". No, seriously, they are great I have 5. The trick is to get them interested in doing things - he will be out in the shed making moulds in no time - just like sand castles at the beach. I am glad that you are finding the videos interesting and above all informative. That's why I put the out there and its nice to know that I am having at least some success... Martin
@@olfoundryman8418 LOL, that's what I did with granddaughter when she was 2~3 (she's 15 now) Grandsons mother has 'issues' (bipolar) I don't get to give him back (I have 2 stepdaughters, younger one had kids early)
This video reminds me of a story I heard about the development of the Harrier jump jet. They needed to control the rotating jet nozzles on the sides of the aircraft and thought that they would probably need a fancy servo mechanism to do that but that would take time so for the prototype they went with a bicycle chain, wound around the cylindrical part of the nozzle attached to a small motor placed in a suitable place. This worked so well that the finished aircraft also had, you guessed it - bicycle chains.
True vintage Aussie engineering, looks rough, works fine. Great stuff.thanks for sharing.
Andy, " true vintage Aussie engineering" a comment that gladdens my heart, thank you very much! Sharing is my pleasure, Martin
Lol bud cubcadet garden teacher in the 70s had the same motor set ups like this universal joint ain't nothing wrong with it works the best has for years love your work very intelligent man and mentor thank you
Shane, You are right, it does work well but it looks a little crude 😊.... Martin
Holy grail of sand preparing for casting. If people can just find what you have shown here. Thank you.
Hardly the holy grail! but it does work well, I wish more people could find it here too! Martin
Cool and innovative shop made machine, thank you.
I always thought it funny that a painter's house needs paint,
A plumbers house has drips,
A foundry man's shop is welded together tid bits.
Burn, It is a crude and roughly constructed machine - it was just a trial with the intention of building a bigger better one if it worked but it worked so well that a better one was not necessary. There are some cast bits in it and on most of the things I have made cast parts are used. I recommend that people build a machine like this rather than or at least in addition to build a sand muller. But Yes, the electric metal glue gun is a great device 😊… Martin
Thanks for taking the time to show us this very valuable piece of equipment and how it works. It may not be a muller, but if you think about it your sand gets mulled to some extent every time you ram it into a mold.
Jack, I have always hankered after a real muller - many times been on the cusp of building one but they are a lot of work and I managed without one for many years. A friend described what he had seen at another foundry so I imaginered my aerator from what he said. It s not a muller - totally different action but it seems to substitute very well plus it leaves the sand nice and fluffy whereas a true muller leaves the sand a bit compacted, some foundries first mull the sand and then aerate it through a machine like mine for the best of both worlds. While both would be nice I value the aerator the greater and its an easy build... Martin
Thanks for taking the time to show the inner workings of your contraption. If it works, that's all that matters. Nice job!
Thank you for your comment. For a quick roughie the machine does work remarkably well. I will be interested to see what improved variants others come up with. Martin
I had planned on Petrobond sand and finding or building a Royer for it. This looks like the ticket for green sand and possibly Petrobond too. Thanks for showing your elegant solution.
Driftless, I have to issue a note of caution here. My sand aerator does not like sticky sands - nice new green sand is so strong that it tends to clog the aerator and if it is at all on the wet side it is very hard to get it through the machine. I have never tried the machine with petrobaond sand so I do not know if the machine will handle it. I believe if the machine was 8 inch diameter instead of the 6 inch that I made it and if it had a 1 hp motor instead of the 1/2 hp it might have a better chance with the petrobaond. If someone wants to turn up here with some petrobaond I will try the machine on it because I would like to know if it will work too. But it sure works well on my sand... Martin
What a great teacher you are. Thank you for sharing.
Oscar, Thank you For saying so - sharing is my pleasure.... Martin
So excited when I saw you posted a new video :) Absolutely the best channel I have seen on casting. Thanks sooo much and please keep them coming.
Jack, Thank you very much for your comment. I wild endeavour to keep them coming, Martin
I've been considering how to reprocess my sand, this seems like a lot easier solution. Thanks, Nice videos. Nebraska, USA
Larry, This type of machine was suggested to me by a friend who saw on in operation at a large foundry. I built this one "on spec" never having seen one at all, it was all a guess. But it was an easy quick build (certainly compared to a muller) and it sure works well, mixes and fluffs the sand up delightfully. The sand feels positively "silky" afterwards.. It is certainly a solution worth a try and even if you have a Muller I would use one of these machines after mulling to "decompact " the sand. I would suggest making it that 2 inches bigger than mine. Glad that you like the videos.... Martin
It's great to see how the experts do things. Thanks for sharing this : )
Geoff, thanks for the comment but nothing really expert here. It is as rough as hessian underwear but it does work well....Martin
Necessaty is the mother of all invention. Great job. Your skills is a dieing art. Love your vids.! From US
TilDeath, Thank you for the comment - I guess I am just trying to keep the skills alive... martin
Great video on your sand aerator, mixer. keep them coming.
John, Nice to hear from you again, how is the sunny north? Trying to keep the videos coming but I seem to be very slow at doing them. How people can do one a week let alone and even one a day as some do has me beaten. Martin
Simple but obviously effective, well done. Peter
Thanks for your comment yes it does work quite well. Martin
I was thinking how to build a muller, Martin to the rescue! Cheers mate!
JB, How is our sunny west? Damn cold over here! This machine is a lot easier a build than a muller. But a muller would be nice too, particularly if you are making up green sand from scratch and you need the mulling action to roll the clay out onto the sand grains. Also for making up silicate sands or other core type sands a Muller would be a good thing, but this machine has certainly done the job for me now for many years. Ideally If one was very serious one would have both mull first and then aerate, but maybe life is too short to build both, Martin
Martin, excellent video, great machine. Thanks again!
Thomas, The machine does work well but I thought the video rather hacked and disjointed, Cecil B DE Mille I aint! But thank you for your comment.Martin
That's great. Ingenious even. Does not need to look shiny so long as it works which it does
Rupert, The machine seems to give the sand a nice silky feel and it rams all the better for having gone through the machine. All my green sand goes through this machine. I do not have a muller and because of this machine I do not need one. Mulled sand benefits from being put through such a machine after mulling... Martin
Cheers
Given that you made this machine @ 30 years ago I think that it proves a couple of points;
1. KISS Principal, Keep It Simple Stupid. Straight drive, no belts to wear or go out of alignment or break.
2. Universal Joint. Not sure that it qualifies as such but it certainly qualifies as a Vibration Free Drive Coupling and I think that no matter how ugly it looks, the proof is in the pudding as this joint has removed any vibrations from reaching the motor and damaging its bearings. It also gives efficient drive and a fail safe sear point should something jamb.
3. Putting some witness marks and numbers on the various shafts and pins will make it faster to service.
Question? Did you cast the aluminium ring and then machine it on your mill?
A thoroughly captivating video for those of us with more than a passing interest in home casting.
Mark
Mark, Have you moved yet? What happened to your visit? You are right about the witness marks but I don't really service it that often :)Yes I did cast the aluminium ring but for another purpose (to hold a cyclone for my vacuum cleaner, way ahead of Dysan) I just repurposed it with a quick bit of turning in my lathe. The video was indeed made for the more serious foundry YTers, Martin
what in the hell are you talking about "crude" my car uses the exact same device to couple my steering column to my steering gearbox, until rack and pinyon steering came about all cars used this design. its NOT crude its ELEGANT . a fantastic design easy to build, reliable, and if it should go wrong very easy and inexpensive to repair !!!!
normdoty, Yes, indeed many older cars did use that sort of universal joint in things like steering shafts. Its not the joint itself that is crude but rather my quick and dirty replication of it 😏. It is indeed elegant in its simplicity and ease of build - as uni joints go it is about the easiest to make and has good ability to tolerate considerable misalignment. Not too sure that I would want it driving the rear axle though 😀 … Martin
I'm rather a fan of using a cordless drill and one of those egg beater looking cement mixers for the casting I do. Particularly nice compared to mixing oil in by hand stirring
Silicone, Yes, I use either a cordless drill or a drill press as a first stage in mixing CO2 silicate sands but I find that it does not do all that good a job so I follow this with passing through a 1/8 inch sieve and then a final hand mix. My aerator mixer device was made only to handle green sand which it doers extremely well producing a fluffy silky feeling sand. I have never tried either a silicate or an oil bonded sand in it. I would guess that it would handle the silicate sand well as it has low green strength, but I suspect that the oil bonded material might cause it to jamb up because of the oil sands high green strength (I am talking petrobond here). Certainly, new green sand which is very strong does cause problems and I have to feed it very slowly a bigger machine say, 8 inch diameter as against 6 may well solve this problem.... Martin
Your universal joint doesn't look crude OR rude to me. I've seen similar devices on automotive steering columns and hot water heating's circulation pumps before. It's actually quite good.
Ron, Thank you for your comment. You are correct, similar joints have been around for a very long time although usually constructed with a little more finesse than mine. I guess that the proof of the pudding though is that it has lasted 30 years or so and is still going strong.... Martin
Very good machine. Thanks for the video.
Yes, it certainly does the job well I am well pleased with it and I am glad that you liked the video. Martin
thank you for your video. I am keen to make one
could you list the modifications that you would do to it if you were to revisit the design.
the specifications so far are:
a true 1 hp motor
1440 rpm
half inch shaft (possibly 5/8 if an 8 inch body is used as there will be more torque).
8 inch body tube pvc
a quarter inch thick rubber walled aerating chamber surrounding the powered rings
two powered rings comprising of 6, half inch (?) bolts
one fixed ring of 6, half inch bolts in between the powered ring set.
one flexible universal joint
bushes top and bottom with shielding to prevent sand entering the bushes.
I would further suggest that there be some feed hopper to assist in the input of sand into the unit.
a further question, how often do the bolts forming the powered ring wear out??
what clearances do you have between the powered bolts and the fixed ring of bolts?
should the heads of the bolts be left on or cut off to bring the bolts closer?
your opinion - instead of the two half rings to hold the fixed bolts would a fabricated ring forming a grate with a slot to slip in between the powered rings be a better solution????
also would you have more bolts on the bottom ring of powered bolts to reduce the spacing - courser spacing on entry , finer spacing on the final stage.
thank you
Charles, You have pretty much nailed it. I would certainly go to 8 inch but it does not have to be PVC tube could be anything that size and solid enough that you can get your hands on. The rubber I use is about 1/8 inch insertion type I replace it every few years as it just hits the rotating bolts sometimes and that wears it away. Top powered ring only has 4 1/2 inch bolts , used to have more but this tended to throw the sand upwards too much and not allow it to move downward through the machine (this is more a problem when the sand is newer or a bit wet i.e. when it is stronger it sort of churns above the top powered bolts and wont go through) lower powered ring has 8 bolts 4 by 1/2 inch and 4 by 5/16 inch (again its what I had and could get to fit!)I too have thought about a hopper but foundry sand does not move well in hoppers unless they are very steep as the sands angle of rest it very high. A vibrator attached to the hopper would probably be necessary I am interested to see what you can come up with. Remember my machine was a proof of concept thing made out of stuff (junk) to hand and other than fiddling with the number of bolts I have never improved the design so improvement should be very possible. I look forward to seeing much improved designsHave never had to replace either the powered or stationary bolts/pins they have worn a bit but not anyway near to needing replacement. Sometimes they have come loose and been thrown out , I just screw them back in, trick is to get the lock nut tight.Clearance between bolts Hmm, good question at a guess about 1/4 inch. I leave the heads of the bolds on (I am lazy! :)) but the heads make it easy to fit and tighten the locknuts note the 1/2 bolts have a flat ground on one side of the head and this flat is orientated to give clearance for the stationary pins.Grate with a slot - not too sure what you mean here, PM me so I can come back to you with an email address that you can send a sketch too and I would be glad to have a look.Bottom ring does have 8 bolts upper 4 and I certainly think that is the sort of way to go, I am contemplating only two or perhaps three for the top ring as a way of improving performance with new (and therefore stronger) sand. Let me know what transpires.Martin
I'm going to try to make one of these. I think this is a great idea!
Marty, Go for it. You will not be disappointed at the job it does on green sand. I would recommend that in line with comments I made during the video you make it just that bit bigger and more powerful than mine i.e. 8 inch diameter and 1 hp motor. Be aware that I do not know how it will work on petrobaond - it may be that it is too sticky… Martin
@@olfoundryman8418 I am using green sand and I am going to follow your advice. I will be using a 1 hp compressor motor. Thank you for reply
Marty, Please let us know how it goes and if you get a chance do a video of the whole process... Martin
GreT as always it's a great steering coloum coupler lol
Robert, Yep, used to have a car with just such a coupler, a bit better built than mine but same idea - works well... Martin
You going to show it working?
John, The customer says he will bring the car around one day soon I will be out with the camera and shoot a video of it running under the bonnet and all if I get half a chance... Martin
So the pins are between the both rotor levels? Do you have a large funnel that goes on top of the inlet, or do just shovel the sand in there? Great work! I've been looking into building a muller for quite some time, if your device works fine, i might build one also. I figure it is rather unsuited for initial mixing of sand with clay or bentonite, but for clearing sand of rocks after casting rather.
rocketryi, Yes the 6 stationary pins are between the two rotor levels. No funnel as damp sand has a very steep angle of rest and it would not slide down a funnel easily. I use a scoop that has about the same diameter as the white aerator body. Remember this machine was an experimental first try - my idea was to build a bigger one if this one worked but it worked so well that a bigger one was not strictly necessary. That said if I was to build it again I would make it about 8 inch diameter and use about a 1 hp. motor. If you gave your sand an initial rough mix on the floor (sand clay water and all) with a shovel and rake for a few minutes and then passed it through the aerator perhaps a couple of times I think you would be impressed with how well it turns out. Even if you do have a muller its worth using an aerator after mulling as it fluffs the sand up nicely breaking up all the compacted lumps that mulling tends to produce. The only problem I have had with the machine is that my new sand (a natural green sand) is so strong that it clogs the machine until it (the sand) has been used a few times and thus it has got a little weaker - I suspect but do not know for sure that petrobaond sand particularly if new might clog it. I suspect that the clogging problem would go away if the machine was just that bit bigger. It is a much easier build than a muller and because of it I have never felt the need to build or use a muller....Martin
@@olfoundryman8418 Hey and thanks for your reply martin! Such a rare thing of a person producing videos on youtube being into actually replying to questions raised, even a while after the video released. Luckily i don't use petrobond, thus will see if i can mititage the clogging problem for my greensand variant. I assume a vibration motor would help solving this (or could make it worse, if the sand further compresses itself because of vibration). If all fails, some kind of rake could be attached above the rotor... i guess i can find a way. Thanks for making an in-depth video on such a simple machine!
rocketry, Clogging is only a problem with very high strength sands (in my case the new sand) I think a home made sand unlikely to be that strong ( I could be wrong of course 😊 ) Sand after a few uses presents no problem at all. I have no idea re vibration - you would just have to try it. I figure a slightly bigger 8 inch (currently 6 inch) machine would probably handle stronger sand way better, again though you would have to try it. Good luck with it all and do let us know how it goes... Martin
@@olfoundryman8418 Your reply leads to the question what the difference between homemade sand and "the new sand" is... Do you mix your sand yourself? Do you have a recipe?
rocketri, My sand is a natural sand i.e. it is straight out of the ground. It naturally has the right sized sand grains and contains some sort of natural clay probably a Kaolin type. Al I do is sieve it to remove the few larger grains and add water to the right moisture level. Sands like this were very common all around the world big deposits were in Albany NY USA for example. Mine came from a quarry about 20 miles from where I live but there once were dozens of deposits around Melbourne here in Australia. The diffewrnce between new and used is simply that sand that is used and sand which is stil as dug out of the ground. So sorry, but no, I do not have a recipe - beyond sieve it wet it and use it 😊... Martin
Hello from Norway!
I am working with granite cuting wire saw and we got a lot off small granitt dusts after cuting work. Is it possible to use it and clay to form models instead sand?
Best regards Darius
Darius, Hello back from Melbourne Australia. Many other materials are used as a "sand" for moulding - zircon, chromite, olivine for example but I have not heard of granite dust being used. Granite is about 20% Silica and 65% Feldspar, Feldspar is quite a refractory material and might perform ok as a moulding sand. To be honest I do not know for certain how it would go but its refractory nature would suggest that granite dusts - providing they are not just granite flour - might be worth a try. However granite contains some mica and this tends to expand a lot when it is heated and this may cause problems. If you have no other source of a suitable moulding "sand" the dust may be worth a try, so give it a go and let us know how it went.... Martin
I"ll try soon !@@olfoundryman8418
Thanks for sharing this. I collecting the bits to build an 8" version. The 1HP motor is 1725 RPM. Do you think it will run too fast? Has anyone shared their designs with you. It would be interesting to see other peoples take on the machine design.
Dan, Sharing was my pleasure, thank you for watching. Your speed will also be the quicker for the increased diameter, in mine the tip of the rotor bars does about 2300 feet per minute however with an 8 inch diameter and 1725 RPM the tip speed will be about 3600 feet per minute, a bit more than a 50% increase. Will it matter? I honestly do not know but I doubt it. I think that at this higher speed the machine will process the sand much quicker and that's a good thing. When I built mine I had very little to go on other than a vague description from a friend who had seen one in use on just the one occasion. It was very much a matter of "suck it and see" hence my construction was quick rough and a bit small and meant only as a trial of the idea with a larger better built effort in mind if it all went well. As I think I mention in the video it went so well that I have never bothered with the better version. Only one other person who built a machine with a similar purpose some time ago has contacted me. His design is rather different and by the looks of before and after photos of the sand it does not seem to fluff it up perhaps quite as well, also I suspect it may have been a bit slower in processing the sand. So, alas, I have no other "takes" on design, You are the first that I know of to be making a similar machine to mine since I put the video out. So I guess that you too are in a bit of a "throw it together and hope situation" although perhaps with a little more to go on than I had. Hey, its a simple machine so as they say in the classics - what could possibly go wrong? :) Good luck with it, I await the results of your effort with great interest please keep me informed. I think that you will be very happy with the results, I was..... Martin
I will. So far I have the motor, a 3/4" shaft and matching bronze flange bushings. Dan
Dan, Sounds like a good start, you are well on the way. I am impatient to hear how it all goes :).... Martin
Watching this again I noticed your rotor has a mix of bolts and studs and maybe two sizes. Is there a reason for this? Still sidetracked on the lathe and master mill which mounts to it.
@ 16.24, were you a gynecologist in a previous life..? sorry, couldn't help it. Nice stuff. Yes, think I'll knock one up. Have built a muller, as you say, bit involved. Oh, and Nice, really nice.
Good lord No, I could not think of anything worse. Occasionally Ok,😏 but every day all day, no thank you! I agree with you on the muller I have almost continually contemplated building one but it is just so much work to do so and so much else to do and the older I got the less use I would get out of it. Tried to buy one but the size I wanted is quite rare and much sought after. If I had been into petrobond sand which (apparently) one just about must have a muller for I would have built one years ago. In truth once I built that aerator the need for a muller went away - for me anyway and I note that even after mulling people with an aerator pass the sand through it as it fluffs the sand up to a nice silky feel that rams well. if you build one you will love it... Martin
Just a thought.... What if... I have a concrete mixer. A simple consumer product like Baumr-AG or Kartrite machine... If I (struck through) When I try this "method" I share the results 🙂
Andrey, What you are suggesting has been tried in this video th-cam.com/video/Y0-lx95NLRs/w-d-xo.html Note that he is using it on petrobond sand but it should work with green sand too (I think!). This really acts as a sand muller NOT an aerator. Mullers tend to compact sand whereas an aerator tends to fluff it up in a nice feeling uncompacted way. If I had a muller I would use it to mix the sand properly but I would then pass the sand through an aerator like the one in my video here. However I feel that this aerator does the job of a muller as well as an aerator.
Love that 5.5KW spindle 24000 rpm - wow nice. My old mill (1985 Dyna 4400 DM ) has only 4KW and just 4800 rpm. What do you use this spindle on?... Martin
Hey Martin, how often do you need to replace the bolts and what size are they? I'm building one very similar to yours, But a little smaller. Mine is just gonna be an attachment for a drill press. From the video, it looks like your top row (spinning mixer) you only have 4 and they might be 1/2". The second row looks like 4 => 1/2" and 4 => 5/16". For the outer ring I'm going to tempt fate and make it out of 4" ID steel tube.
OMM, I have never had to replace the bolts. I have had one or two come loose and need to be screwed back in. Remember there is a row of 6 stationary rods between the two rotating rows, these are 1/2". Your guess is right as to the size and number of the rotating bolts. If I had to guess I would say that you will be disappointed with a smaller machine. Mine tends to clog when the sand is new and strong and in these circumstances needs to be feed very slowly - I suspect that petrobond will also tend to clog it (never tried) as I think it is a strong sticky sand. I suggest actually building it bigger say 8 inch diameter with about a 1Hp motor as I suspect this would help with the clogging. I was always going to build mine bigger as this one was only a small trial to see if the idea worked but it handles the sand so quickly (once the sand has been used a bit) that I never bothered. Please do let me know how you get on. I will be interested to see if a 4" version will work and if so how well.... Martin
@@olfoundryman8418 Martin, I plan on doing 2 stationary rods (but again 5/16 screws) above the beater to take care of bigger chunks and eight stationary rods between the beater rods. The drill press motor is 2 hp.
Omm, 2 Hp should be way more than enough for a quite big machine! However I think that stationary bolts above any of the rotating ones may just serve to hold the sand back as foundry sand tends to "hang back" unless something (like the rotation) makes it move. Also 8 stationary rods with just 4 inch diameter does not leave much room for the sand to move through. I don't really know of course as I only ever built the one machine and never tried any variants so my suspicions /guesses etc could be way off. Please let us know how you go - do a video on it perhaps…. Martin
@@olfoundryman8418 I'm doing a full step-by-step document of it at "The Home foundry" forum. As I mentioned to you before there is quite a few good guys there. But if you just want to follow along, forums.thehomefoundry.org/index.php?threads/how-do-you-re-purpose-green-sand.1107/#post-27235
And I will do a full video once the build is complete.
I built a similar machine years ago with a little different design on the pulverizer. How can a fella post a picture in the comments? I would send out a photo if I could.
Centaurus, I am not surprised that there are other machines out there, after all I copied one (sight unseen) that I had been told about. What does surprise me is that so far you are the only other constructor to come to light! Any other makers out there? I imagine that considerable design variation would be possible would out adversely effecting the machines function. Unfortunately I do not know how to post a picture in the comments I have never seen one so it may not be possible. I would be interested to see your design so can I suggest that you PM me and I can send you an email address that you can send a picture to. Martin
Centaurus, I am not surprised that there are other machines out there, after all I copied one (sight unseen) that I had been told about. I am perhaps a little surprised that you are (so far) the only other constructor that has come to light, any others out there? Unfortunately I do not know how to post a picture in the comments,I have never seen one so it may not be possible, pity I think! However I would very much like to see your machine so if you wish you can PM me and I will come back with an email address that you can send a picture too. Do you still have your machine, do you still use it, and have you tried it on Petrobond? Martin
Martin, I have not used it for Petrobond as I never could get past the stink of that stuff so I stuck with the clay bonded sand. I sent you a PM so if you would like I can send you some pix.
Centaurus, I have actually replied to your Pm, did so about 19 hours ago. Let me know if you did not get my reply as I can probably do a copy and paste to resend (a bit long to retype!) I did include my email address so you can send those pictures. I would very much like to see them...Martin
OK it was there but the email did not work when I tried. Replied through PM to check EM address.
how does it work?
jack. The rotating rods break up any lumps in the sand, mix it all properly, and aerate it so it sort of fluffs up and makes it feel as close to silky as its possible for sand to feel. After passing through this machine the sand rams much better and makes a better stronger mould.....Martin