Love your work dude, but you have to remember that all that gas/vapour has to go somewhere. You have to burn out your pattern or SERIOUSLY vent your mould. And even then... But, I absolutely LOVE your rocket stove foundry! Gotta get me one of those!
One thing you should also keep in mind (if you don't already) when doing parts like this is shrinkage. Metals shrink considerably when cooling down and solidifying from liquid (about 6-8% for aluminium). The exact amount and geometry is very dependent on the part geometry. Bulky, thick parts e.g. shrink more (see cupping on the bottom of ingots for example) and need a large feeding sprew. This shrinking can also cause trouble and destroy the parts and/or molds in some cases. Imagine you were casting a ring around a solid core: The ring will try to contract, possibly crushing the core, cracking and/or ending up deformed. Thank you for sharing your trials and errors! It's highly appreciated. Greetings from Germany
3d scanners are kind of crazy how cheap they've become. These used to be big ticket items you'd go on a long walkabout to find someone with them. Yeah the casting is a hard job for sure, the covering the part in a clay-ceramic grog/slip was how I was shown to do them for bronzes and things and then just burn or melt out the inside prior to the pour. A few other things I learned was that you can sometimes just want a little extra 2-5% bigger to account for metal shrinking a tiny bit when it cools. Maybe not an issue so much on some parts but it might be something to keep in mind for others Also welder's spats are something I can't recommend enough for pouring metal, it means it rolls off your shoe instead of sitting on top of it The wood foundry is working great though! Got to be happy with that
The thought of molton metal pouring into my boot is enough to make me want to go and buy some spats right now🔥 That's good to know about the shrinkage It might be worth casting some parts in taking some measurements before and after to see how much.👍
What I've been doing for castings is dipping my part in sheetrock mud first (watered down so I get thinner layers that don't crack as bad). Then I pack the whole thing in sand. Preserves the details pretty well.
Use the foaming light weight pla 2 layers. Brush on plaster, vent from the top, and pour really slow to ensure the gasses escape and the pla is consumed
You should be able to dial in a "casting mode" in the slicer yourself. It might take some tweaking based on the model geometry but generally you want to go for lightning/tree infill with as low a percentage as possible and as few walls and top/bottom surface layers as you can get away with. With the part you're trying to cast, I'd be tempted to make the sprues triangular, bring them all planar with each other and print it in the same orientation as you did the first one (motor mount plate on the bed). This should give you a part that's easier to print with a single wall and doesn't need much internal support for the top surfaces (by minimising their area and bridging distance). My guess is that with some tweaks you could get this to print successfully with one wall, one bottom layer, 3 top layers and 5-10% infill. Caveat: I have no experience doing lost plastic casting but lots slicing and printing.
The best way to do this is to print your part as perfectly as you can-- then cover it with silicone to make a mold-- then split your silicone mold and peel it away and fill it with polystyrene.. Then you pack your sand around the polystyrene mold. Granted this isn't very likely going to be cheap, but you can get the best results this way.
You should use a hard wax for your pattern if possible.either way, youneed to put the mold in a furnace hot enough to burn out your pattern. You can then lightly 'puff' any ash out (if you used plastic) and then reheat the mold and pour your aluminum. You should also add a bit of oil to your sand so it stays together better when you are compacting the sand around the pattern.
Hi there! Your part, you print it with 100% filling and in my opinion it will be as solid as the aluminium part... After that, you'll have to see if there are any constraints in terms of operating temperature. Nice work though.
Have you looked into Polycast PLA? It burns out with less ash than regular PLA. Though, at double the cost of regular PLA, you would want to weigh the pros and cons first.
True if you had a CNC machine that would be the best option. I only have a manual mill so 3D printing and casting is technically a more viable option. Or it would be if it worked. I think of a bit more time I'll get it down pat.
Love your work dude, but you have to remember that all that gas/vapour has to go somewhere. You have to burn out your pattern or SERIOUSLY vent your mould. And even then...
But, I absolutely LOVE your rocket stove foundry! Gotta get me one of those!
One thing you should also keep in mind (if you don't already) when doing parts like this is shrinkage.
Metals shrink considerably when cooling down and solidifying from liquid (about 6-8% for aluminium).
The exact amount and geometry is very dependent on the part geometry.
Bulky, thick parts e.g. shrink more (see cupping on the bottom of ingots for example) and need a large feeding sprew.
This shrinking can also cause trouble and destroy the parts and/or molds in some cases.
Imagine you were casting a ring around a solid core: The ring will try to contract, possibly crushing the core, cracking and/or ending up deformed.
Thank you for sharing your trials and errors! It's highly appreciated.
Greetings from Germany
3d scanners are kind of crazy how cheap they've become. These used to be big ticket items you'd go on a long walkabout to find someone with them.
Yeah the casting is a hard job for sure, the covering the part in a clay-ceramic grog/slip was how I was shown to do them for bronzes and things and then just burn or melt out the inside prior to the pour. A few other things I learned was that you can sometimes just want a little extra 2-5% bigger to account for metal shrinking a tiny bit when it cools. Maybe not an issue so much on some parts but it might be something to keep in mind for others
Also welder's spats are something I can't recommend enough for pouring metal, it means it rolls off your shoe instead of sitting on top of it
The wood foundry is working great though! Got to be happy with that
The thought of molton metal pouring into my boot is enough to make me want to go and buy some spats right now🔥
That's good to know about the shrinkage It might be worth casting some parts in taking some measurements before and after to see how much.👍
Nice work i like how your rocket stove has now evolved into a forge and ugly but functional is a win in my book
What I've been doing for castings is dipping my part in sheetrock mud first (watered down so I get thinner layers that don't crack as bad). Then I pack the whole thing in sand. Preserves the details pretty well.
Use the foaming light weight pla 2 layers. Brush on plaster, vent from the top, and pour really slow to ensure the gasses escape and the pla is consumed
You should be able to dial in a "casting mode" in the slicer yourself. It might take some tweaking based on the model geometry but generally you want to go for lightning/tree infill with as low a percentage as possible and as few walls and top/bottom surface layers as you can get away with.
With the part you're trying to cast, I'd be tempted to make the sprues triangular, bring them all planar with each other and print it in the same orientation as you did the first one (motor mount plate on the bed). This should give you a part that's easier to print with a single wall and doesn't need much internal support for the top surfaces (by minimising their area and bridging distance).
My guess is that with some tweaks you could get this to print successfully with one wall, one bottom layer, 3 top layers and 5-10% infill.
Caveat: I have no experience doing lost plastic casting but lots slicing and printing.
Really appreciate that info thanks for taking the time to share that 👍
The best way to do this is to print your part as perfectly as you can-- then cover it with silicone to make a mold-- then split your silicone mold and peel it away and fill it with polystyrene.. Then you pack your sand around the polystyrene mold. Granted this isn't very likely going to be cheap, but you can get the best results this way.
You should use a hard wax for your pattern if possible.either way, youneed to put the mold in a furnace hot enough to burn out your pattern. You can then lightly 'puff' any ash out (if you used plastic) and then reheat the mold and pour your aluminum. You should also add a bit of oil to your sand so it stays together better when you are compacting the sand around the pattern.
Hidious but functional is the winning design principle in half my projects!
Hi there!
Your part, you print it with 100% filling and in my opinion it will be as solid as the aluminium part...
After that, you'll have to see if there are any constraints in terms of operating temperature.
Nice work though.
Have you looked into Polycast PLA? It burns out with less ash than regular PLA. Though, at double the cost of regular PLA, you would want to weigh the pros and cons first.
Love Rusty!
Great but, why would you not CNC the part?
True if you had a CNC machine that would be the best option. I only have a manual mill so 3D printing and casting is technically a more viable option. Or it would be if it worked.
I think of a bit more time I'll get it down pat.
Look into 3D printing with polystyrene-- it melts so much easier
The opposite of perfect is adequate.