Refining casting techniques with May

I’m in Castuary* again, this time for May, and trying several experiments with her.

Between crazy contracts in my dayjob, prepping for pate de verre demos and a show, losing Rajah and a whole bunch of other stuff, May and Lily and Annie and Bob and Beeguy and Frank and the Queen and Portland Gothic and Shout have been languishing in the studio in various states of undress. (Yeah, it’s VERY stimulating, being in my studio)

I finally kickstarted myself on Thursday, got stuff in the kiln and began clearing out the logjam. First up: An idea I have for combining pate de verre and tack-fused glass components. Didn’t turn out the way I wanted, but I learned a LOT, parts of the failure are breathtaking, and I’m doing it again the right way. When I get this right, it’ll make spectacular vessels. I think.

While that was cooking I finally, FINALLY, finished up May’s mold and started packing in the glass. Just as a refresher, May is a sculpture I did back in February, of a lady I met in a nursing home.

WARNING: THIS IS A LAB NOTES POST (i.e., VERY long)

I “pulled a rubber” with May, i.e., I made a silicone mold of her, which allows me to experiment with various techniques to resolve issues I’m having with my current processes:

• I’m not entirely happy with the quality of the eyes I’m getting–it usually takes one or corrective firings to get enough dark color in the pupil, and by then the whites fade a bit. I’m still having trouble controlling texture when adding glass powder in a correction, so the less color I need to add, the better. May’s eyes, in particular, need to be blazingly furious–that’s part of the strength of this sculpture–and so they must be dark.
• Nostrils are relatively thin spots in the human face, and that can be a problem in pate de verre–as the powder draws together during firing, it tends to leave holes. That means that the coloring layers behind the surface coats can slide in, disrupting the shading…or you get gaps. I really don’t want to cast the nose as a pre-made inclusion (makes it hard to keep the facial tones consistent), so I need to change my nose construction technique.
• Either my wax steamer is inefficient for something of this size (May’s finished size will be around 16×20 inches or a bit larger), or my investment is incorrectly formulated, because by the time I steam out the wax I’ve got spots of mildly soupy investment surface that can leave scum on the glass (or worse, break down). I need to minimize the amount of wax in the mold, particularly in non-critical parts like the background.
• Packing powder against the investment tends to produce an abraded color akin to stonewashed jeans, thanks to pate de verre’s bubbles. The Vignettes need deep, rich, saturated background with no signs of bubbles, to help the face pop out and look luminous.

I think I can solve most of these problems with a few process changes. (and all you casters out there, please, PLEASE chime in with suggestions if you have better ideas)

Goal 1: Reduce wax steamout
First, I’m greatly minimizing the amount of wax that goes into the investment. I poured an absolutely paper-thin model of May in wax, then added wax struts in back to help her keep her shape. The struts are only loosely attached, and once she’s invested I’ll pull them away. That will keep wax volume–and time in the steamer–to a minimum.

Second, rather than constructing the entire sculpture out of wax, I’ll only use wax for the head. The background itself will be an “inclusion,” i.e., a sheet of clear glass. That way the steamer can concentrate on clearing only the head, instead of having to steam out a huge mold.

Third, I’m not going to work this mold as wet as I usually do, to keep water damage to a minimum. I’ll get the color layer (powdered glass only) into the face quickly, while the mold is still wet…but then I’ll let it dry naturally while I pack in the usual pate de verre mix (frit schpritzed with water, mixed with gum arabic), with a little more gum arabic than usual. By the time I get to the background the mold should be nearly dry. I can’t pack the background anyway (since it’s got a sheet glass surface), so I’ll simply add layers of dry powder and frit.

Goal 2: Produce darker, more saturated (and flatter) backgrounds
Using sheet glass against the mold surface instead of packed powder should have another benefit: An absolutely flat background with a bubble-free surface. Frit behind sheet stays fully saturated and colorful, so I’m hoping this will solve the “stonewashed jeans” problem but still allow me to mix colors. And I’ll be able to hand-sand the surface without wearing off the surface layer and breaking into a bunch of tiny bubbles. It’ll also let me play a bit with drawing hidden images on the glass, something I love to do.

Goal 3: Make consistently shaded, successful noses
I reconstructed May’s nose to create the illusion of thin nostrils when, actually, her nose is now pretty much one solid piece with minor indentations. I’ll add some darker shading underneath to increase the illusion.

Goal 4: Better eyes on the first try
Classic figure sculptors in bronze and stone use negative space to simulate the transparent lens of the eye. The pupils are actually carved-out holes with a tiny stub left for specular highlights (see right–image courtesy of Phillipe Faraut, master sculptor and instructor). The hole is bigger or deeper, smaller or shallower, to simulate eye color.

I’m working in glass, not bronze or stone, so I have the advantage of transparency. Rather than copying traditional techniques, I’ll try using transparency the way it’s used in a real eye. On this attempt, I’ll place a clear glass frit ball directly in the model, pushing it into the pupil but leaving it about an eighth of an inch above the surface of the eye. I’ll invest the mold against it, as an inclusion.

Just as with the background, that will give me a pupil volume of clear, bubble-free glass instead of bubble-abraded color. It will also act as a magnifying lens into the eye. I’ll back the bubble with black and dark amber, so that you see INTO the dark pupil, just as you would with a real eye. I can grind the pupils down to the surface of the eye if necessary or leave it proud, whichever gives the strongest effect.

This post is more than long-enough, so I’ll stop here. In the next post, I’ll go through how I actually built this thing. Hopefully, if I do enough of this, it’ll get me through Castuary with minimal agida.

Please note: This lab note is one of a series of posts detailing May’s creation. If you’re interested in reading the rest, click these links:

• The inspiration for the sculpture “May”
• The constructing of May’s clay model
• The making of a silicone mold of May
• Planning May’s mold (this post)
• Making the mold
• Packing the mold
• Decanting May
• May the second (final version)
• Taking the girls for a stroll

———————-

*Castuary: That anxious period when the mold is in the kiln and it’ll be several days before you find out if you’ve just made heaven or hell in glass.

Share on Facebook

Related posts:

1. May I: The decanting Castuary is over and May-the-first is out. "Castuary" is that anxiety-ridden period...
2. Testing colors and kilns I'm trying to see just how little clear powder I can get...
3. Investing May Once I've finished the model of May, my portrait of a lady...
4. Molding May To the left you see one of the sculptures I'm working on...
5. Packing May Once I have an invested, finished mold for May, it's time to...