Metal Casting Zone

Has anyone out there used steam casting techniques on a mold larger than for jewelry.
If so how large a casting were you successful pouring? Am wanting to use about 20 to 40 ounces of aluminum in this way and not blow off any body parts with the steam back pressure.
Let mev know please.
Thanks, Don

Im a little leary of the steam casting, years ago i was caught in the face with a serious steam burn that literally made my skin slide off. Im planning on doing a couple of experements with vacumn casting useing a shop vac, seems like a safer approach, when I do I will post the results good or bad.

20 to 40 ounces??? thats about 1 kg??? what do you want to cast?? i regularly pour that amount and have found no need to do a steam cast. a simple steam cast is a tin on a stick with a damp rag in the bottom. you place the can over the sprue. but!!! if you are working by yourself you want have time to see to the crucible and then grab your steamer. an assistant would be needed.

Thanks, for your responses,
I'm casting little statues that have long thin arms and legs and the aluminum tends to freeze before reaching end of mold chambers. Using plaster coated foam molds ( I've even disolved the foam with acetone,which helps with gas pressure)and used a multitude of vents as well. So far about 65% to 75% are complete when removed from mold.
Was thinking pouring into a resevoir and adding steam to speed up movement of the ali that I'd increase the success rate. This would require a better device than a jar lid and stick type tool and probably require a porous dental type of casting plaster mold.
What do ya think?

an actual dental investment would be much better, i did find a recipe for a DIY investment that is equal parts POP and silica flour with wood flour added in to give porosity but id did not specify how much wood flour. I migh experement with it later but the savings arent that great to really worry about it much.

You are right , I said plaster (I guess it really is) but I meant investment. It seems to let the steam and gasses pass through without needing so many vents.
Another thing I haven't tried on my lost foam molds is to p[reheat the whole mold plaster and support sand etc. before pouring ( might work as well as steam,maybe)

aonemarine wrote:
an actual dental investment would be much better, i did find a recipe for a DIY investment that is equal parts POP and silica flour with wood flour added in to give porosity but id did not specify how much wood flour.

I had seen that reciepe before and went and picked up some POP and pulverized some sand to dust and got some wood dust, then I couldn't find the reciepe.

It's 1 to 1 POP to Si dust, plus some wood dust? I think the wood dust burns out to allow for venting of the gases.

Blindpig, you could try vacuum casting. Kind of high in initial cost but a vacuum set up is very useful for several things in casting.

www.preciousmetalswest.com/videos_for_broadband.php
This looks like a good site, I haven't looked at too much on here. Vacuum Casting with Hydrogen Gas Torch is a good video and cool music.