Greetings from beautiful Millville NJ! I’m down here for a few days at Wheaton Arts’ Creative Glass Center of America, where I had an artist in residency way back in 1992. My friends Jim Harmon and Hank Adams invited me down to prototype a workflow for taking digital 3D designs to glass objects. Take a look and see what I’ve been up to!
The TC Wheaton Glass Building at Wheaton Arts
The Studio is a recreation of an 1880’s Glass facotory and hosts world acclaimed artists coming to realize their work in glass.
I chose this Duchamp Chess Set Pawn (http://www.thingiverse.com/thing:305639) as a simple form to test how PLA prints will fare burning out of plaster molds. I wanted to have something with a wide bottom so we could easily inspect the interior of our mold. I am curious to see how much residue PLA 3D prints will leave behind when burned out of a plaster mold.
I used some wax to seal any holes in the Print, and then used a cardboard box to prep a form for casting plaster around the object. Note that I used some clay to fashion a reservoir/base for the 3D print.
I mixed a 50/50 mixture of pottery plaster and sIlica- this is a standard formula for glass casting as the mold will need to be fired to 1500 degrees Fahrenheit.
I gave the form a wet splash coat of plaster first.
I was nervous about the piece floating off the bottom of the box, so the splash coat was there to anchor it and capture the surface. As the plaster began to set I added more in on top.
After the plaster set, Jim and I removed the castings from the cardboard and dug out the clay reservoir.
The PLA 3D print is just visible inside the plaster mold. Next up, we loaded these molds in an oven and slowly brought them to 500 degrees, then all the way up to 1000 to completely burn off the PLA overnight.
The burned out mold was perfectly clean in the morning.
Next up, the molds were flipped and loaded with chunks of glass cullet.
We picked chunks that were clear and as big as we could fit in the reservoir. This will help the casting be clear with fewer bubbles.
Ready for firing!
Jim programmed the oven to slowly heat to 900°, then climb up to 1500° as quick as possible, then hold there for four hours.
At that point the glass was all melted into the mold and we cracked the oven to “crash” it back down to the annealing temperature of 900° before the glass devitrifies.
The oven was pretty hot!
We are soaked the oven at annealing temperatures of 900° and 720° on the way down. Hopefully the pieces will be cool enough to remove from the oven before I leave tomorrow! Stay tuned to see how the castings come out- I can hardly wait to see myself!
UPDATE: See how everything came out here: http://thegreatfredini.com/2014/07/26/pla-perdue-part-two/