OK, glassists: What’s the first thing we learn when we start working with glass?


Right? Sigh.

So I’ve got a potential client who’s asked for samples of work done in my “onyx glass” (her term)–i.e., a mixture of Bullseye Light Peach Cream and Crystal Clear, which make the most gorgeous warm honey tones I’ve found. The combination literally lets you dial in exactly the shading and translucency you want just by varying percentages and frit sizes.

Wonderful stuff, and I use so much of it that I mix it up and store it in 5-pound batches. Which is why it was right there and ready when it was time to pack and fire a test tile. Took it out of the kiln last night and got one of those heaven-and-hell surprises you get in casting sometimes. Still needs a bit of cleanup coldwork but this is pretty close to done:

jacobeanrose (1 of 1)HOWEVER…somebody wanna tell me where the coral colors came from? Either Light Peach Cream has suddenly started striking really peachy (and only in spots, to boot) or some poor slob–three guesses as to who–contaminated the whole daggone jar of honey mix.

Fortunately, it works for this design–the name of the piece is “I Dreamt the Jacobean Rose.” Not so fortunately, reproducing that color effect could be a bit of a problem because I DON’T KNOW WHAT WAS IN THAT JAR. The contaminant looks like Salmon Pink, but since I rarely use that color it’s probably something else that incorporates a miniscule amount of my favorite hot colors, possibly Pimento Red or maybe even Orange. LPC is mildly reactive, so I could also be seeing the effects of a color reaction (although I’ve never seen reactions go pink before).

Given what’s come out of the studio since this jar was used, it’s most likely a leftover undertone layer for facial skin. I suspect it’s something like a third- or fourth-layer mix, mostly crystal clear powder diluting a tiny amount of pimento and amber, maybe a tad bit of LPC. In such small amounts it would have read as the slightly warmer white of honey mix and so into the jar it went. Good reminder that I should keep any unused frit jar off the table when I’m in a frit-packing frenzy. Otherwise it’s “dump now, clean up later,” and stuff like this happens.

Sigh. This is why we keep notes, date frit mix jars and keep our nicely-labeled color samples. I should be able to narrow down the range of culprits and figure out how to add this effect to the repertoire with a couple of tests.

And we’re gonna be a LOT more careful about what we stick in the frit jar next time, aren’t we?


Addendum: Well, it ain’t Pimento or Salmon. I suspect the contamination is coming from Sunset Coral, although I’ll probably never know for sure.

Three months after this post, I examined this tile and found that it has cracked multiple spots. Each crack outlines the darkest of the tinted areas pretty nicely, which usually signals compatibility issues. I thought at first that I might have dropped or struck the piece, or that incorrect annealing might have had a hand.

So I encased the tile again in refractory, fired it with a tripled annealing cycle, cleaned it up…and waited. About a week after firing, the cracks reappeared in the same places. I’ve since repeated this tile five times with everything from the REAL honeymix to clear billet. Those tiles have been fine, and look great in the polarimeter.

So I’m thinking it’s a compatibility issue. Drat.