Lost PLA Casting: First Try at Casting 3D Printed Parts in Aluminum at Home. 

Haha! Between you and “this old tony” I’ve spent a small fortune on metalworking stuffs! Thanks so much for the vids, love em! Isaac

Can I just say that you are my favourite RU-vidr. The vids are great and informative, but the best is your commentary......love it. Please keep making vids, especially casting related......5k subs here soon!!!

Hey Paul I feel ya pain mate nothing worse than spending all that time getting everything done then failure🙄welcome to my world. I just did a vid on brass casting in plaster of Paris after melting out the wax molds I thought it would work great but after pouring in the brass the moisture in the plaster bubbled and carried on and the brass didn't get the mold details at all . Still made 2 cool ingots. I'll have that vid out in a few days if your still subbed my friend. I liked your comment about it not being a fail if you learn something so I recon I've learned bloody heaps 😬👍🏻.

I love the sense of humor he has, just makes it all the more better!

Investment powder is what you really wanna use. POP is still dangerous to attempt this with. Tends to hold too much water which can cause explosions of molten metal. Plus if you don’t burn out the wax or pla well enough it can also cause a sudden explosion of metal. The investment plaster once properly dried and baked is also porous so it will allow the flow of metal easier and you can pop it on a vacuum chamber to help get it all through the mold.

Love your videos man

Hey your a lot further ahead of me. No such thing as failure as long as you keep trying.

Thanks for the great idea. Just need to figure out how to do it right, and then making a cup of aluminum is pretty awesome. Waiting for your next adventure, thanks for sharing!!

When I've tried lost wax casting its been tough to get all the wax to melt out. I used a camp fire at first, but that cracked the plaster, so I used plaster bandages to hold it together, and that worked really great and is pretty cheap. I then tried to bake out the wax in the oven, but I still never got all the wax out so when I went to pour thick black smoke came out and thats no good. PLA can technically work, but the melting temp of it is pretty high in comparison to wax, so you've really gotta crank up the heat to melt it all out. Plus, with a block of plaster (that will initially insulate the PLA from the heat of your burner) you've to heat up the entire block before the PLA will even start to melt, and its not going to flow out like wax will, you really need to just burn it out at a high temp. I have heard of someone who put their plaster mold in the microwave to melt out the wax, and apparently that worked really well, but I don't think PLA will flow or microwave very well. Also, casting something at thin as that cup is tough because once the metal goes in the plaster mold that is below the melting temperature of the aluminum, the aluminum will cool very quickly and solidify before it reaches the bottom of the mold. Aluminum conducts heat very well, so by the time the first bits of aluminum cool, the rest of it will start to solidity very quickly aswell. 1/4" is the thinnest I've been able to pull off casting with wax, and PLA is gonna be tougher than that. You should look into re-using plaster, it would be great to have a way to recycle that stuff because of how expensive it is to buy over and over. With my wax casting, I often just coat the wax in thick plaster then wait for that to set, then cover it in plaster bandages. Does the trick pretty well.

Paul, one thing I've used to increase the heat when doing a burnout is to get a terra cotta pot, wrap the outside in aluminum foil, tap a few small vent holes in the top (and a handle of some sort, I used a 3/8" eye bolt.) Basically it domes the mold, which conserves heat and makes the burnout more even.

You should try Green sand casting ☺

hey paul why didnt you vitrify the plaster mould?

Add vents!

if you ever want to give it another shot, i can highly recommend a mix of sifted sand, about 5% (by weight) montmorillonite clay, and a good 1% pinch of salt. with some water it gets sticky enough, that you can even mould it around an object by hand, without anything crumbling. and because the sand is only thinly coated with the binder, it remains permeable and dries out much quicker than plaster and without shringage. (probably also reduces the risk of air bubbles) so far i have only tried this to cast small objects from tin, but the molds withstand glowing red without loosing integrity, and start to break down after soaking for a few minutes. PS: to get super smooth surface details, paint the object with plaster first. also montmorillonite is very interresting stuff, worth looking into. it has a thousand uses.

I see what went wrong, you didnt get the mold hot enough. Usually you mix the plaster 50/50 mix with play sand, then pour it in around the mold. That makes it hold up to much higher temps than the straight plaster would, which would just crack. Usually you would heat it to at least fully glowing red hot so that it's glowing inside of it to fully burn it out and pour the metal into it while it's still blistering hot inside. Thats why you usually see people that do investment casting using two furnaces, one as a burnout kiln/to keep it hot, and the other to melt the metal. If it's fluxed, Ive had it flow into parts as thin as that easily, expecially since you have the larger sprue on top giving the head pressure. The only thing I can say to do different would be to glue some bendy drinking straws to the bottom and put it to the top of the mold so that when it's all burned out and you pur the metal in, the air will go out of the straws and you wont end up with air boles in the casting. Also, the bubbling and smoke you saw was from steam, you needed to get it to around glowing hot and keep it there for at least 30 mins to drive out all moisture completely.

Good try Paul. Not sure why it fail although thin molds are tough. Try a smaller and more solid object next time. Something like an action figure.

Thats a nice rock

Put in a vent hole to let the air out.

Every time I have seen somebody do lost PLA, they have done their burnout in the oven. Maybe that gets you a more uniform heat so that the PLA melts better?

you need to do a full burnout at 800f for hours on your plaster mold and the plaster needs reinforced with sand and possibly fused silica (or just buy investment). Merely melting out the pla isn't enough, you'll get bubbles and nasty stuff in your pour from leftover PLA that gets in the pores of the plaster..same with lost wax. They sell burn out ovens for a good reason. :)

Paul, you are either going to need a backyard fire to heat that thing or a pottery kiln. Check your craigslist, old pottery kilns are a dime a dozen. I paid 25 bucks for mine. I run ceramic shell on wax (and now foam apparently) and use the kiln for burnout prior to pouring. I know ceramic shell is not cheap like PoP, but I'm thinking your PLA will burn out without expanding and cracking the ceramic shell. I haven't tried PLA yet but willing to give it a whirl.

have you tried printing with HIPS? Its High Impact PolyStyrene and i reckon would burn out of the mold much much easier than pla?

Need to watch lost wax casting lol You can drill a hole in the stem You have a cup lol Failure is a start to greatness!, Keep it up so I don't look bad when I try your projects It makes me look smart!, lol Enjoyed

How long did it take for the wax to melt out ?

try investment plaster, it comes apart easily when you put it in water

Try first making a silicone mold of the mug so you can remove the pla part. Then using plaster to cast a wax mold of the mug. Then you can use a oven to melt the wax.

You should give the wall compound dip method a try. That to me looks like the most practical method. But I've only ever seen the dip done on foam. The results are fantastic though. You can see the foam bead texture in the aluminum it holds details so well. People do it to get around all the sand mix nonsense. Well, it simplifies flasking too. There is none. They take the dips and put them in buckets of dry sand to pour. The downside is it is a lost process. There's no way to make a reusable pattern and dip it. To burn out people usually use ovens too. Lots of foam pours people don't even bother burning out. They just pour the aluminum right on the foam. It flames out. But with an even dip maybe you can melt your plastic out easier? I've never seen it tried. No one does what you did with the bucket of plaster though. Now we know why. Clean up of dips is easier too. Once the metal has solidified, but is still hot the dip gets pulled out, set on the ground, and hit with cold water from a garden hose. That pops the dip off the casting.

my question is: Do they sell spools of wax to run through the printer head so you can make a traditional wax melt vacancy within the plaster? You are assured that the wax will melt.

I'll put a link in the description below; so you could make yourself an equally 'Crappy' coffee mug.🤯

after I poured some aluminum ingots and they cooled sufficiently I could hear them tinkling from the inside.

3:44 you should probably make a handy tool for moving the crucibles. like that thing in the bottom right of the screen. you said something about being careful a minute earlier 5:57 failure? the right wording is "learning experience"

Next time Dump the plaster in the water while it's still hot. The plaster will basically boil away from the casting inside. Did that in high school when the metal shop teacher was teaching about lost wax casting and we made rings for some stupid reason.

Wohoo! New video. Yes im a little late, but it still worth a big wohoo! :)

08:15 Thanks.

Dangerous as in boily or dangerous as in toxic gases or radiation?

I was about to say to myself "man he's smart! He uses his furnace to heat up the plaster to prevent catastrophic explosion while melting the metal AND the remaining plastic inside the mould!" Then you removed it and let it sit for some time.. :D Jokes aside, the 3D printed thing might be too resistant to heat? I've used high density polystyrene foam for my few attempts at casting and found it burns REALLY well (although not too eco-friendly and it sends little black thingies flying eveyrwhere (and it smells horrible)).

if at first you do not succeed try again lol the point is ur having fun doing this even with failure...wouldnt be fun if u didnt fail at first some of the mess ups leave the best results really enjoy ur vids keep them coming!

You are not wrong. Do not google that thing about plaster of Paris. Google very helpfully put a terrible photo right at the top of the page.

my old highschool welding teacher tried to make a hand mold, she didnt think it through...

add vents

Try with lost wax

Please put on boots. You're dorky, and self deprecating, but you dont deserve injured toes & such. Okay Paul? Please? Like work boots when investing? Ty.

New plan: A Fighting Type Pokémon . . . Or a Dragon Type. They are better are everything.

Nice try anyway!

did you lose weight?

6th 😋

hey paul where did your pla go? hahahhahahhahahahahahahhahahahahahhahah not funny lol