Wednesday, April 8, 2009

Progress report...

I don't have much to show yet, but I thought I would give a progress report. Our last bronze pour was April 1st, and it went very well. It was a pretty large pour relatively, as we needed 3 full crucibles (each holds ~100 lbs of bronze).

I have two pieces from this pour, which together set me back a little over $300 for the bronze and the shop supplies. I broke both pieces from them molds last Wednesday, and they both cast beautifully. This is great news, because I'm still using the short cut method of skipping the mother mold process. Usually you sculpt the form you would like to cast, then using silicone you make a rubber cast of the form. Then, you pour hot wax into the mother mold to make a replica of the original. You refine the wax mold, proceed with sprue and gates, then build the plaster mold. The plaster mold is then heated for a day to totally melt and evaporate out all the wax leaving the void where the bronze will pour into. By skipping the mother mold step, I sculpt directly in wax. This results in a faster turn around time, but I have no backup in case something goes wrong in the plaster casting, or bronze pour. If it goes wrong, I've lost that sculpture entirely.

The first sculpture I broke open is my dragon head. In the interest of minimizing the mold size, and therefore the cost, this piece was fairly tightly cramped. In order to pour this in one mold, I needed to cut the horns off the head, and gate them as a part of the cast. So, it took nearly 3 hours just to saw off the sprue and gates. I stopped with that, since I really want to finish my "secret" project first.

My second sculpture from that pour was good, but there was a void near where the gate attached which I needed to fill with some small scraps and a welder. I removed all the excess gates and sprues, then cleaned up the piece pretty much and did the welding (oxy/acetylene). Most of the weld went well, but there is one spot I need to go back and fill again. I think I will get set up on the MIG welder tonight and weld that one spot, and then also I can work on welding the horns back onto my dragon's head.

Tonight I will take some pictures.

1 comment:

Gary Rith Pottery Blog said...

Hey, have missed ya dude, and thanks for the progress report here. Hope things are good with you, gr