Since you're doing a gravity casting instead of centrifugal or vacuum assisted casting, you're going to need larger sprues for the metal to flow, probably about eight to ten gauge wax wires. The main reason your parts aren't casting fully is that when you pour the aluminum in, the air/gas in your mold isn't forced out through the porosity of the plaster, as it would be with a vacuum casting or centrifuge. It's like trying to fill a water balloon by putting water in your mouth and blowing it into the balloon. It's just going to get messy. ;) You made a good step with having a pour channel, but it would be easier for you to have your model anchored to a hemisphere of clay or wax, about the size of a ping-pong ball. That forms what's called a sprue button. Then, run gas exit sprues from the top of each piece in your model back to the floor of your casting flask. It'll look like a weird umbrella. Keep them about a half inch away from the hemisphere/sprue button. When you pour your molten metal, pour into the button and watch for it to flow to the holes left by the umbrella sprues as it forces the air out and occupies the cavity left by your model. Try it first with pewter/Britannia metal, since it melts at lower temperature and stays fluid longer. Aluminum should stay molten long enough to run through the whole model, though.
It's nice to see how you explain the different mistakes you've been making, which for some (like me) have taken years to learn. Thanks for your contribution
Increased head pressure by raising the height of the sprue. Make a fine plaster slurry and make a thin coat over the model to give better details. I use ransom and randolph investment with fiber for extra strength (I do large vacuum casting) so I'd also recommend adding very fine fiberglass in small quantities to your investment. Great job though!
Ransom and Randolph Ultra-Vest is fantastic. Add a pinch of boric acid to the water if your casting plastic/resin. Makes the investment a little bit harder so it doesn't crack when the plastic expands during burnout.
Sometime after I fix the Z-Axis wobble issue on my 3D printer, I'll do a "DIY Casting Plaster Recipe Revisited" video. Make some improvements and see how it stacks up against Ultra-Vest. I'd love it if I could make an investment plaster almost as good with just Home Depot ingredients!
11th try: I would make a quick vacuum chamber. A cheap vacuum pump, a round piece of 1/4" thick aluminum, a steel pot, a gasket and some fittings. The whole setup costs less than a single perforated flask and you can use it with your soup cans. You can emulate the perforated flask effect with 4 small straws along the edge of the soup can. Any sort of flask casting shouldn't use vents like you've got there. That's a good technique for sand casting, but leads to poor results with a flask. There are some other minor changes that should be made, but really you were on the right track. Cheers and good luck on your next ten tries at a random task.
I think you should look up vacuum pouring. Look up --> Microwave Kilns, Lost Wax/PLA/Resin casting with a Vacuum Cleaner . You can also try sand which lets out the air .
Tape at end of straw. Use this to make a vent for air to come up. Have second vent to pour aluminum in. Problem with sand casting is having bad vents that trap air.
Right!? There are other improvements sprinkled through the other casting videos (e.g. alloying the Aluminum with silicon in the sandcasting video), but I probably improved the most here
From another engineer who is learning how to cast aluminum, I'd like to share a nugget of critical information with you and your viewers. The surface tension of molten aluminum is ~14 times higher than water, so it requires a higher pressure than you might think to conform to mold details. Vacuum casting creates a ~1atm pressure differential between the sprue and the mold to force the aluminum into the tight spaces. ~1atm is 407 inches of water column, Aluminum specific weight is ~2.6, so to compete with the vacuum results, you would need a 13ft tall sprue.
Hey, don't you bring math into this! You wouldn't happen to be one of those engineers who actually got to take classes on fluid dynamics, would you? I feel like it should be more complicated than just comparing the flow with water. Also, that's assuming differential pressure as opposed to removing air so it isn't trapped, displacing the aluminum. Also, I tend to imagine aluminum more like runny pancake batter than water haha. With electrical, the only flows we talked about were of electrons, magnetic fields, and "holes", so if you have any more formal experience with fluid dynamics (compared to my almost 0 formal experience with the subject lol), I'm certainly open to discussing further!
@@TenTries I am one of those engineers who took fluids and heat transfer and all that, but I still spent a summer making failed castings to learn the ins and outs. You are right on track thinking of it as pancake batter, and trapped air is a problem, but even with perfect venting, the mold details like gear teeth just won't fill well without a higher pressure to overcome the surface tension. Soon I'm going to start casting large pieces, so that will have a whole new set of challenges, like the molds don't fit in my kiln to do the burnout procedure.
I probably should mention that I used pop can aluminum for this video and part 2 as well. In the sand casting video, I alloyed 8% silicon to reduce the surface tension, and the difference was huge. It traveled a lot further up my gas vents than I expected. Forgot to get actual diameter, but it was less than 1mm. I'll have to try the gears again with the silicon alloy and set up a vacuum system to see the difference. I'd bet that the gears would look like gears with the alloy, but to function as gears for any reasonable amount of operation time, I'm betting they'd have to be vacuum cast and touched up with a file. Probably still not as good as machined. Only one way to find out for sure! How large are you thinking?
@@TenTries I use 6061 aluminum so it is weldable and I can have it nickel plated (chrome) for car parts. My longest part is about 4ft long, and my heaviest part is about 25 pounds, so the sizes are all over the place. I'm going to have to build a custom mold burnout box for each mold probably, maybe I can achieve it by stacking loose ceramic bricks and just laying a heating element inside the volume. I have an idea for vacuuming these molds for casting by basically vacuum bagging them with a hole in the top to pour. It doesn't have to be pretty or last for very long. All of the parts I am casting are for my 1937 Pontiac Coupe, so they have to be perfect or they don't go on the car. As you mentioned, the surface tension of pure aluminum, which is basically what soda cans are, is higher than alloyed aluminum, but all alloys still have really high surface tension compared to other metals, and the lower density means less pressure in the mold so it's a double whammy. Try casting the same thing in aluminum, and copper and the difference will surprise you.
@@DavidChadwell 6061 is a pretty bad material for casting, silicon content increases the fluidity (decreases surface tension), so alloys designed for casting like 319 or 356 are far better, and can be heat treated to very close to 6061-t6 properties. I'm an art degree person, but took some of those fancy pants math classes you guys do ;)
Try zinc ,? plaster only needs to be dry and 500to700f to prevent cracks in molds. Casting and extruding (popcan )aluminum are quite different materials.
Something that should be tried is after the pour hold the mold/can firmly with the pliers and take an electric sander without abrasive attached turn it on and hold the rubber/velcro cushion against the handle of the pliers for a bit before it solidifies to see if it can move trapped air to the top and out of the casting.
hi! first, thanks for the videos!! i'm doing a matrix and them help me a lot. I want tell you can be a posibility youre usenga normal dish soap but in some contrys or compani's solding a ultra concentrate dish soap. I divide in to 6 mi especific dish soap (ALA Fron Argentina) and i have a wonderfull result (in the especificactions it tell what a tablespoon, 15ml is yields in 6 litros of whater) i replaced a 12ml from your target mix for 2ml thanks a lot! and sorry but i suck on maths. worst on inglish
Nice project, but how do you think VOG got better results using straight Plaster of Paris? His early coin pour was before he got the Kaya Cast with the vacuum chamber. It would have been nice to get a good look at the PLA print before pouring plaster all over it. Just to know what the final result was supposed to look like before the resulting pour. Did you make the layer lines that thick intentionally, is the last mitation of your printer or we're the the lines a result of the pour/plaster?
Could you provide a link? I'll have to approve the comment when you do btw. I'd have to look closer at what VOG did. The venting must have been pretty good and I'm guessing he used a better aluminum alloy. This was just pop can aluminum, so it was pretty thick (more viscous) compared to an aluminum & silicon alloy that is typically used in casting. The printer has a terrible z-wobble issue and that is probably the banding you are seeing. I've been printing with another printer lately that doesn't have that issue
@@TenTries Ah, he used an investment plaster. (Wish I knew what kind) Paster of Paris was used for something ng else. He also built a vacuum chamber and had a vacuum machine. All the rest seemed, more or less, the same. The vacuum casting he did a couple of videos Later with a DIY vacuum pump was pretty good too.
3D Solutech usually, but a lot of other brands work too as long as it is "natural PLA". Theoretically, there should be no ash bc there are no pigments and PLA burns (or boils, more likely) away cleanly
If i tried this i would make the plaster mold in 2 steps, first i would paint the plaster on with a brush in a thin layer so that no air bubbles are present, then i would place it in the cup and add the plaster around it.
brother I also think about making my own channel like you (experiment world) I really feel inspired by you, do you have any advice before opening my new channel.
But.. Did you use some melting flux for aluminum? The problem appears to be in aluminum. In my opinion part of the problem is in the aluminum, then in a test the aluminum appears slightly golden, it happened to me too and when it happens in that area it cracks. I think it is due to the tin of the can in which I had poured it, and I seem to have seen that a couple of times you used a can as a crucible, you have to use a graphite crucible, absolutely no tin in contact with aluminum and if you suspect some aluminum mixed with tin, throw that material away, don't try to reuse that
In tries 1-9 I used lite salt for flux. I was using a 304 Stainless cup for my "crucible". I wouldn't recommend using a stainless steel "crucible". The lite salt was causing corrosion where it was touching the stainless steel. For try ten, I placed a few lumps of charcoal in the furnace to produce a reducing environment. It seemed to be about as effective as lite salt without corroding my "crucible". I had thought there might be iron contamination, but figured the color should be throughout the metal, if so. I am not sure why 7 turned so golden and only one or two of the others are even slightly golden colored. Since tin cans are tin-coated steel, it's possible that what you saw and what I saw are iron contamination, not tin contamination. The color only being on the surface may be attributable to iron in the aluminum reacting with the plaster. Regardless, I bought a graphite/clay crucible. I just need to get around to making tongs and a second furnace.
@@TenTries Also, instead of "burning out" PLA, could it be heated to ~ 70°C and majority pulled out the hole with some dental tools or something? I wonder if soot ruins the surface quality?
@@TheAndyroo770 The burn out cycle also removes chemically bonded water in the plaster. (Needs temps much higher than 100C, 212F) This ensures that the investment doesn't blow up when molten aluminum is poured in
@@TenTries Sure but for certain molds, you may be able to get the melt just right and the sprue hole big enough to just pull out the PLA then continue to "dry"/burn out the mold casing? Just throwing out my thoughts
@@TheAndyroo770 That could reduce ash if you did it just right. Some guys spray a little air in to flush it out. I have a video idea on the list along the lines of "how ash is ruining your casts", but that idea is going to need a lot of research
After this, I'd suggest the rest of the videos in the metal casting playlist: ruclips.net/p/PLrK4Q8TY7X89NFVn6eRogJW-qd3A-fiBE I was hoping to have a casting giveaway video this weekend, but it didn't work on the first try. I'll have it done next week, so check back soon!
Since you're doing a gravity casting instead of centrifugal or vacuum assisted casting, you're going to need larger sprues for the metal to flow, probably about eight to ten gauge wax wires. The main reason your parts aren't casting fully is that when you pour the aluminum in, the air/gas in your mold isn't forced out through the porosity of the plaster, as it would be with a vacuum casting or centrifuge. It's like trying to fill a water balloon by putting water in your mouth and blowing it into the balloon. It's just going to get messy. ;)
You made a good step with having a pour channel, but it would be easier for you to have your model anchored to a hemisphere of clay or wax, about the size of a ping-pong ball. That forms what's called a sprue button. Then, run gas exit sprues from the top of each piece in your model back to the floor of your casting flask. It'll look like a weird umbrella. Keep them about a half inch away from the hemisphere/sprue button. When you pour your molten metal, pour into the button and watch for it to flow to the holes left by the umbrella sprues as it forces the air out and occupies the cavity left by your model. Try it first with pewter/Britannia metal, since it melts at lower temperature and stays fluid longer. Aluminum should stay molten long enough to run through the whole model, though.
It's nice to see how you explain the different mistakes you've been making, which for some (like me) have taken years to learn.
Thanks for your contribution
Glad it was helpful! You're welcome. Guess that means I'm really good at making mistakes! 😄
Increased head pressure by raising the height of the sprue. Make a fine plaster slurry and make a thin coat over the model to give better details. I use ransom and randolph investment with fiber for extra strength (I do large vacuum casting) so I'd also recommend adding very fine fiberglass in small quantities to your investment. Great job though!
Thanks for the tips!
Ransom and Randolph Ultra-Vest is fantastic. Add a pinch of boric acid to the water if your casting plastic/resin. Makes the investment a little bit harder so it doesn't crack when the plastic expands during burnout.
Sometime after I fix the Z-Axis wobble issue on my 3D printer, I'll do a "DIY Casting Plaster Recipe Revisited" video. Make some improvements and see how it stacks up against Ultra-Vest. I'd love it if I could make an investment plaster almost as good with just Home Depot ingredients!
Amazing work! Thank you for showing us your tries!
11th try: I would make a quick vacuum chamber. A cheap vacuum pump, a round piece of 1/4" thick aluminum, a steel pot, a gasket and some fittings. The whole setup costs less than a single perforated flask and you can use it with your soup cans. You can emulate the perforated flask effect with 4 small straws along the edge of the soup can.
Any sort of flask casting shouldn't use vents like you've got there. That's a good technique for sand casting, but leads to poor results with a flask. There are some other minor changes that should be made, but really you were on the right track.
Cheers and good luck on your next ten tries at a random task.
That might have to be a future video!
@@TenTries VOG also has a video on a cheap homemade vacuum setup, although he upgraded to a commercial one eventually
I think you should look up vacuum pouring. Look up --> Microwave Kilns, Lost Wax/PLA/Resin casting with a Vacuum Cleaner . You can also try sand which lets out the air .
Tape at end of straw. Use this to make a vent for air to come up. Have second vent to pour aluminum in.
Problem with sand casting is having bad vents that trap air.
Now these were great advances!
Right!? There are other improvements sprinkled through the other casting videos (e.g. alloying the Aluminum with silicon in the sandcasting video), but I probably improved the most here
From another engineer who is learning how to cast aluminum, I'd like to share a nugget of critical information with you and your viewers.
The surface tension of molten aluminum is ~14 times higher than water, so it requires a higher pressure than you might think to conform to mold details.
Vacuum casting creates a ~1atm pressure differential between the sprue and the mold to force the aluminum into the tight spaces.
~1atm is 407 inches of water column, Aluminum specific weight is ~2.6, so to compete with the vacuum results, you would need a 13ft tall sprue.
Hey, don't you bring math into this! You wouldn't happen to be one of those engineers who actually got to take classes on fluid dynamics, would you? I feel like it should be more complicated than just comparing the flow with water. Also, that's assuming differential pressure as opposed to removing air so it isn't trapped, displacing the aluminum. Also, I tend to imagine aluminum more like runny pancake batter than water haha.
With electrical, the only flows we talked about were of electrons, magnetic fields, and "holes", so if you have any more formal experience with fluid dynamics (compared to my almost 0 formal experience with the subject lol), I'm certainly open to discussing further!
@@TenTries I am one of those engineers who took fluids and heat transfer and all that, but I still spent a summer making failed castings to learn the ins and outs. You are right on track thinking of it as pancake batter, and trapped air is a problem, but even with perfect venting, the mold details like gear teeth just won't fill well without a higher pressure to overcome the surface tension. Soon I'm going to start casting large pieces, so that will have a whole new set of challenges, like the molds don't fit in my kiln to do the burnout procedure.
I probably should mention that I used pop can aluminum for this video and part 2 as well. In the sand casting video, I alloyed 8% silicon to reduce the surface tension, and the difference was huge. It traveled a lot further up my gas vents than I expected. Forgot to get actual diameter, but it was less than 1mm. I'll have to try the gears again with the silicon alloy and set up a vacuum system to see the difference. I'd bet that the gears would look like gears with the alloy, but to function as gears for any reasonable amount of operation time, I'm betting they'd have to be vacuum cast and touched up with a file. Probably still not as good as machined. Only one way to find out for sure!
How large are you thinking?
@@TenTries I use 6061 aluminum so it is weldable and I can have it nickel plated (chrome) for car parts. My longest part is about 4ft long, and my heaviest part is about 25 pounds, so the sizes are all over the place. I'm going to have to build a custom mold burnout box for each mold probably, maybe I can achieve it by stacking loose ceramic bricks and just laying a heating element inside the volume. I have an idea for vacuuming these molds for casting by basically vacuum bagging them with a hole in the top to pour. It doesn't have to be pretty or last for very long. All of the parts I am casting are for my 1937 Pontiac Coupe, so they have to be perfect or they don't go on the car. As you mentioned, the surface tension of pure aluminum, which is basically what soda cans are, is higher than alloyed aluminum, but all alloys still have really high surface tension compared to other metals, and the lower density means less pressure in the mold so it's a double whammy. Try casting the same thing in aluminum, and copper and the difference will surprise you.
@@DavidChadwell 6061 is a pretty bad material for casting, silicon content increases the fluidity (decreases surface tension), so alloys designed for casting like 319 or 356 are far better, and can be heat treated to very close to 6061-t6 properties. I'm an art degree person, but took some of those fancy pants math classes you guys do ;)
Try zinc ,? plaster only needs to be dry and 500to700f to prevent cracks in molds. Casting and extruding (popcan )aluminum are quite different materials.
What kind of aluminum are you using. My instinct would be to break up some large cast aluminum part like a transmission housing or some such.
Something that should be tried is after the pour hold the mold/can firmly with the pliers and take an electric sander without abrasive attached turn it on and hold the rubber/velcro cushion against the handle of the pliers for a bit before it solidifies to see if it can move trapped air to the top and out of the casting.
hi! first, thanks for the videos!! i'm doing a matrix and them help me a lot.
I want tell you can be a posibility youre usenga normal dish soap but in some contrys or compani's solding a ultra concentrate dish soap.
I divide in to 6 mi especific dish soap (ALA Fron Argentina) and i have a wonderfull result (in the especificactions it tell what a tablespoon, 15ml is yields in 6 litros of whater) i replaced a 12ml from your target mix for 2ml
thanks a lot!
and sorry but i suck on maths.
worst on inglish
Subscribed!
Thanks!
Nice project, but how do you think VOG got better results using straight Plaster of Paris? His early coin pour was before he got the Kaya Cast with the vacuum chamber. It would have been nice to get a good look at the PLA print before pouring plaster all over it. Just to know what the final result was supposed to look like before the resulting pour. Did you make the layer lines that thick intentionally, is the last mitation of your printer or we're the the lines a result of the pour/plaster?
Could you provide a link? I'll have to approve the comment when you do btw. I'd have to look closer at what VOG did. The venting must have been pretty good and I'm guessing he used a better aluminum alloy. This was just pop can aluminum, so it was pretty thick (more viscous) compared to an aluminum & silicon alloy that is typically used in casting.
The printer has a terrible z-wobble issue and that is probably the banding you are seeing. I've been printing with another printer lately that doesn't have that issue
@@TenTries Ah, he used an investment plaster. (Wish I knew what kind) Paster of Paris was used for something ng else. He also built a vacuum chamber and had a vacuum machine. All the rest seemed, more or less, the same.
The vacuum casting he did a couple of videos
Later with a DIY vacuum pump was pretty good too.
what brand of pla are you using. I see very little ash and you are at lower temps
3D Solutech usually, but a lot of other brands work too as long as it is "natural PLA". Theoretically, there should be no ash bc there are no pigments and PLA burns (or boils, more likely) away cleanly
If i tried this i would make the plaster mold in 2 steps, first i would paint the plaster on with a brush in a thin layer so that no air bubbles are present, then i would place it in the cup and add the plaster around it.
That sounds a bit like ceramic shell casting
brother I also think about making my own channel like you (experiment world) I really feel inspired by you, do you have any advice before opening my new channel.
Go for it! The best advice I can give is to post your videos before you think they're ready. Then, you can learn as you go.
@@TenTries ok thanks
and can you please try investment casting I think that one is better than this, sorry for too many demands
This is technically investment casting. I want to do some vacuum casting at some point to get a little better results
But.. Did you use some melting flux for aluminum? The problem appears to be in aluminum.
In my opinion part of the problem is in the aluminum, then in a test the aluminum appears slightly golden, it happened to me too and when it happens in that area it cracks. I think it is due to the tin of the can in which I had poured it, and I seem to have seen that a couple of times you used a can as a crucible, you have to use a graphite crucible, absolutely no tin in contact with aluminum and if you suspect some aluminum mixed with tin, throw that material away, don't try to reuse that
In tries 1-9 I used lite salt for flux. I was using a 304 Stainless cup for my "crucible". I wouldn't recommend using a stainless steel "crucible". The lite salt was causing corrosion where it was touching the stainless steel. For try ten, I placed a few lumps of charcoal in the furnace to produce a reducing environment. It seemed to be about as effective as lite salt without corroding my "crucible".
I had thought there might be iron contamination, but figured the color should be throughout the metal, if so. I am not sure why 7 turned so golden and only one or two of the others are even slightly golden colored. Since tin cans are tin-coated steel, it's possible that what you saw and what I saw are iron contamination, not tin contamination. The color only being on the surface may be attributable to iron in the aluminum reacting with the plaster.
Regardless, I bought a graphite/clay crucible. I just need to get around to making tongs and a second furnace.
Add sodium silicate to the casting mix?
That might be a good idea for aluminum casting! Since it melts around the same temperature as copper, bronze, and brass, it might not work for those
@@TenTries Also, instead of "burning out" PLA, could it be heated to ~ 70°C and majority pulled out the hole with some dental tools or something? I wonder if soot ruins the surface quality?
@@TheAndyroo770 The burn out cycle also removes chemically bonded water in the plaster. (Needs temps much higher than 100C, 212F) This ensures that the investment doesn't blow up when molten aluminum is poured in
@@TenTries Sure but for certain molds, you may be able to get the melt just right and the sprue hole big enough to just pull out the PLA then continue to "dry"/burn out the mold casing? Just throwing out my thoughts
@@TheAndyroo770 That could reduce ash if you did it just right. Some guys spray a little air in to flush it out. I have a video idea on the list along the lines of "how ash is ruining your casts", but that idea is going to need a lot of research
I would try sand maybe.
That video is coming!
👍💓!!
where is the next video -_-
After this, I'd suggest the rest of the videos in the metal casting playlist: ruclips.net/p/PLrK4Q8TY7X89NFVn6eRogJW-qd3A-fiBE
I was hoping to have a casting giveaway video this weekend, but it didn't work on the first try. I'll have it done next week, so check back soon!
El aluminio bastante malo
Desculpa, não entendo espanhol
Eleventh try: Use commercial casting plaster to compare results.
It's on the list! 😀
11 try? vacuum
I'll have to do that before too long!