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Okay boys and girls; some of you may remember my comments about encasing rocks in glass, and some of you may remember some of the stuff I've said about pot melts. Well, here's one that combines the best, or worse, of both.
It measures 12" and is of Spectrum series 96. I set up a two pot melt to let the glass flow around the rock. Then added the double border. Haven't quite decided if I'm going to slump this or put it in a round rim as a garden accessory. Regardless, it's a rock from the rocky coast of Maine encased in my representation of the ocean. O, no comments about the background; you wouldn't believe what I had to do to take this picture.
Well, if that's as big a piece of the coast as gets removed, there isn't much of a problem. Anyway, as hard as I've worked on that thing my guess is that the cost would prevent most folks from buying it. The truth is that I make weird stuff like that for the shop because it causes a ruckus and gets attention. Then people usually buy something else. We shall see.
Have you looked at it through a polarimeter to check the stress? I'd be surprised if it stays together for long. But then again, if you've cold worked the rim of the poured blank and refired it you've already stress tested it pretty well.
Charlie,
After I got the glass and rock together, I cooled it over a very conservative annealing/stabalizaing cycle and let it sit up in a window to see if that very thing would happen; it didn't
Then I fused on the two piece, three layer border, again cooling very conservatively and set it up in a window to see if that very thing would happen; it didn't.
Today I have it slumped and currently cooling. Once it is done, I'll set it up in a window in my showroom and see if it stays together. BTW, there are several others in the showroom where I actuall encased the rock by drapping the glass entirely over the rock, and they've done just fine.
Guess it's the good life I lead, or I just got very lucky several times in a row.
Look at it through a polarimeter to see if there is any stress around the rock. If there isn't, you've got something there . If you see stress, it will go eventually .
I hope it's stress free. What kind of stone is it? Maybe you can create a market for 90 or 96 coe stones .
If you can create one with the stone outline in the shape of Squirrel Island in Maine, I'd be interested in it for my Aunt and Uncle as a gift. Perhaps that's your market. The islands of Maine, or the coast lines...put little lighthouses on top of the stones that are lampworked???
Well, I never got one of those stress meters. Usually I check how hard I'm pushing down on my glass cutter and that tells me how much stress I'm under; O, wrong kind of stress.
In an earlier post I mentioned that I had a couple of fully encased rock plates that had been in the showroom for quite a while and showed no signs of giving up the ghost, so with Spectrum and coastal Maine granite/quartz, maybe I stumbled on a COE match. Only time will tell.
Now, about Squirll Island; guess I've got to go look at it to see what it does look like and see if I can find one that fits the bill. As for the small lampworked light houses, That's not the kind of thing I have any interest in and probably never will, but thanks for suggesting it.
BTW, this baby will finish up slumping by mid morning on Tuesday after a VERY long cooling cycle. I'll post something then.
I don't want to carp on this, but you have to be careful, especially if you plan to sell these. A polarimeter is nothing more than a couple of pieces of polarized filter and a light source. You can make one with the lenses out of an old pair of polarized sunglasses.
A glass under stress can hang around just fine for a long time, then spontaneously shatter. A very small scratch can set if off instantly if it is under tension. If it shatters in a customer's hand or near their face, you may be liable and could be sued. Leaving it in a window isn't enough testing. Some people run their pieces through a dishwasher a few times. I still think that is no real replacement for a polarimeter.
If the rock and the glass are not compatible there is no amount of slow cooling and annealing that will cure that. The glass will be stress free at the annealing point, (around 960 F) but both the rock and the glass have a lot of shrinking yet to go through on the way down to room temperature. So stress builds back up and can't be released. The next time they warm up they will expand at different rates, which may temporarily either increase or decrease the stress level. It may be that the glass is under more stress when it is cool.
To get into the physics of it a bit, the glass can be under either tension or compression, (it's being either stretched or squeezed.) If it is under compression you may be in luck. Compression would develop if the rock shrinks less on cool down than the glass -- so the glass is trying to squeeze the rock into a smaller size, but of course the rock won't let that happen. If you scratch the surface of a glass in compression, the stress is still trying push in, so it tends to squeeze the scratch closed. The surface of tempered glass is under compression, but its interior is under tension.
If the rock has shrunk more than the glass, and the two are stuck together, then the rock is pulling the surface of the glass in towards it (away from the rim), and the glass is in tension. If you scratch the surface it will almost certainly crack instantly as the stress is trying to pull the scratch apart.
How do you tell compression from tension in this type of arrangement? I don't know. The safest thing is no stress at all.
Jerry wrote:...about Squirll Island; guess I've got to go look at it to see what it does look like and see if I can find one that fits the bill. As for the small lampworked light houses, That's not the kind of thing I have any interest in and probably never will, but thanks for suggesting it.
Jerry
It's shaped like a squirrel . The lighthouse suggestion was a joke...kitsch...tourist trade... Somebody is bound to do it. Everytime I've been on the coast of anywhere, there are lighthouses in snowglobes, on baseball caps, on shot glasses...
Talk about bad luck. I decided to slump this baby only to have the mold break in the process. It broke on the way up so I have an unusual line wandering though the water. Too bad; it was a great sized mold. It may be salvagable but just now I ain't in the mood.
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. The lighthouse suggestion was a joke...kitsch...tourist trade... 