"Lost Wax" Bronze Casting from 3D Printed Piece

Last week, I took a free class at the public library on 3D printing.

COMMUNISM!

The library has a Makerbot Mini, and the class was using software called Tinkercad, by Autodesk. I've played with Google Sketchup as well. Tinkercad is super easy to use and I skipped ahead several lessons during the class to get to the good stuff. Didn't really make anything I wanted to print off. And, in fact, not really sure at this stage what I would use for, except maybe as an offering for my students.

Obviously, the plastic pieces could be Old Skooled into molds for waxes, with the digital file as the master. It's nice to mix old and new, even nicer to get old stuff to do new stuff.

The librarian teacher said the plastic was actually polylactic acid, which is meltable and burnable. I said I do metal casting at Harper College, give me a piece and I'll cast it in metal and you can show it off in future classes.

He gave me a knight chess piece. So, I invested it in a jewelry flask, burned it out and spin cast in bronze. Nothing at all new there. Shapeways does this all the time.

So, I treated it like lost wax with same burnout schedule. Heat to 400F, hold for two hours, heat to 1350F to burn out carbon, hold for 1 hour, cool to 900F and cast. The librarian told me the piece took two hours to print. I probably could have carved it in an hour. Total time from plastic to metal was 1 day (overnight).

Here it is:

Here is a close-up of the piece. Got a nice laminar look to it. You can see the "granularity" or resolution is about .2 mm.

Could have done a better job of spruing so it didn't have defects, but what the hey, it's rapid prototyping. I don't know where this 3D printing stuff will go. Could be a fad. For all we know, they'll get a bioenigneered tank of bacterial slime or coral reef to grow all this Thingiverse stuff just as easily.

But in the meantime, fun!

Melted Metal!

This past Saturday, my Bronze Casting class had their pour. It's a once a semester thing. I'd prefer to do it more often, but my students don't produce enough stuff. Enough talk, more pictures!

Here is a picture of me and my foundry assistant of the day, Adam Bacon, pouring molten bronze into a mold. The mold is ceramic shell, which is a very thin tough ceramic material that you form around a wax model, and then melt the wax out. The bronze is around 2000F, which is why we wear the Spaceman Spiff suits. You notice how Adam is crouching? That's because...

Adam is 6 feet 8 inches tall. Yes, he's a big boy.

More than half of my class are retired. That's not unusual. Of those, at least half again are little old ladies. They are in the thick of things like nobody's business. We also get little young ladies...

Some so tiny they can barely get the crucible out of the furnace. That doesn't slow 'em down, though. Heres' a shot I'm including only because I looked at it and thought "Oh, my god. It's my dad!"

I'm shouting at them to pour faster. But, you know, in a nice way!

Lastly, here's an interesting shot from last spring. I quit smoking back in September. The reason the following is an interesting shot now is, back then you couldn't find a picture of me where I didn't have a cigarette to hand:

Hopefully, those days are behind me.

Anyway, we had fun, and nobody got hurt.