Thaddeus

I know there's some metalworkers here... I was out in the garage staring at my bronze/aluminum furnace and thinking: boy I'd love to cast some of my own aluminum parts... I need to get some green sand though, I don't want to use the resin bonded stuff (too toxic). Haven't done any casting in a few years but now would be a good time to start...

Thanks

Thaddeus

keith

You've got a bronze/alum furnace?

I want to be your friend.

jim968

Thaddeus... try Brodhead-Garrett at 1-800-321-6730; they used to carry 50 & 100 lb. barrrels of "Petrobond" sand. Dunno if they still do, they've been moving away from school foundry supplies over the past few years. My 2000 catalog doesn't show a web addy; they may have one by now.

BTW, y'all do know how to do lost foam casting with styrofoam, plaster of Paris, and dry contractor's sand, yes? Of course, you have to make a new pattern for every piece....

Keith, you can make your own furnace for aluminum. Burns charcosl & uses a shop vac for draft. Construction was really simple, IIRC. I need to find the link anyway for a video we're making next week; I'll post it here when (if?) I do, or you can look for the FAQ page for news:rec.crafts.metalworking. I'm pretty sure it'd be referenced there.

Jim, who knew some of his trivia would be of use someday

Thaddeus

No, my experience has been with draftable forms that can be withdrawn from sand, and lost wax. I have always used resin-bonded sand at (you guessed it) a University foundry. The last time I took the sculpting course I built a small furnace.

I want to try to use the green sand because (1) it's reusable and (2) it's not so toxic. Alkyd Resin is NASTY. Is Petrobond a reusable medium? From what I've read, the green sand is held with some oil compound... it's an older method (um, about 5,000 years older) but should work out for the sort of stuff I want to do.

Anyway, I think it would be a rush to drive in a car with parts I cast myself. Also cheaper! Not hard to find tramp aluminum to throw into the pot... pick up some propane at the local convenience store, fire up the Kirby and go! Also useful for scaring conservative neighbors when it's roaring away in the driveway. "WHAT IS THAT THING? A JET ENGINE?" ... which is what it sounds like. Also the blue flame shooting out the top is visually striking.

Thaddeus

jim968

Thaddeus, the Petrobond sand we've got is dark red in color. Yes, it uses an oil binder, and is reusable. We've been working out of the same 50 lb. barrel for the past ~7 years, making maybe a 10-20 small castings a year. Since this is a lab for our MEC & DFT students in Manufacturing Processes, we're just using a low-melting point lead alloy, so we're not really burning the oil out in our use.

B-G used to sell the oil for reconditioning the sand, but I think you'd need access to a muller to make use of it (or do a _lot_ of stirring!).

Great image of the furnace, BTW! Ours is electric; safer, simpler, but much less visually interesting...

Jim, "The early bird gets the worm, but the second mouse gets the cheese...."

Thaddeus

Here's another image:

Thaddeus builds furnace. Thaddeus decides to fire up furnace to cure concrete. Thaddeus decides to turn on air, turn on gas, throw in match. Thaddeus frantically beats at eyebrows to put out flames on forehead.

My method now: ball up and light newspaper, place in furnace. Turn on air. Turn on gas.

No mistake about it: Electric furnaces have some real strong points. Glad to be alive and in one piece.

Thaddeus

Manning

I am so envious I cannot stand it.

I used to help a friend of mine who was in the sculpture department at Georgia State University. That was some of the most fun I have ever had. The freaky green flames coming out of the furnace were insane. And smashing the sand off after the bronze had cooled was an excellent way to releive stress. We would start at around 9:00 at night and finish around 4:00 AM and go to Waffle House all sooty and stinky. And it was even considered an acceptable date with some of the art school girls I went out with.

BTW, GSU is one of the only universities to have an iron foundry. Excellent to play with that as well.

Thaddeus

Yes, University of Minnesota has an iron smelter also. I've helped pour but never did any pieces in iron myself, just aluminum and silicon bronze. Another guy there didn't build a bronze furnace, he built an iron smelter. Can you imagine running one of THOSE in your driveway? Whoa. Smashing up old steam-heat radiators to drop in the smelter. Insane.



Thaddeus

jim968

OK, y'all, here's the link I mentioned earlier... You wanna build your own backyard furnace to melt Al, bronze, etc? How about a backyard iron furnace? Wanna know how to make Thermite? Your own lathe? A steam engine?

For the Al-bronze furnace, follow the "Gingery" links to "Charcoal Furnace"... for all the rest, just enjoy browsing some of the books these people have for sale....
www.lindsaybks.com

Jim, ordering about $100 worth tomorrow...

Thaddeus

That site is so cool! And frankly, I am going to try using charcoal in my furnace. I still feel jumpy about the propane...

Great resource! Thanks.

Thaddeus