Question about glass types

[mattmoss]

Hi, I'm new here (intro in other section). I took a brief look around the forum here to see if I could find this info, but didn't see anything offhand that answered my question. So I'm hoping y'all can point me to another thread here (or webpages elsewhere).

Basically, I'm looking for information on the different kinds of glass typically used for lampworking... borosilicate, COE96, whatever... (I'm not even sure I'm using the right terms here.) I think I've been using COE96 stuff, but I don't recall. Looking for info on advantges, disadvantages, cost, etc.

Mainly, I was interested in different glass from a show I saw, in which a lampworker was basically laying down work, reheating it, etc, without kiln or something to anneal it/cool it slowly. Quite possibly, the show was edited to remove the "boring" stuff, but it didn't seem so. I know that when I work, I have this little blanket that keep my beads inside until they cool to lessen the chance of breaking (although I still get broken beads).

Alternatively, other suggestions to replace the blanket are also welcome. The crafter I learned from suggested a crock pot full of vermiculite, but I couldn't find that stuff anywhere.

Thanks in advance. what a great looking site and I hope to learn tons!

[BillBrach]

Almost without question the lampworker you saw was using borosilicate glass. It has very low COE, at about 33. This is why he/she could come back to it.

But, even with boro, you can crack a piece, especially if it is really thick.

A crockpot is just that, a crock of crap !! They will not keep your beads from cracking. But vermiculite is a much better thing to cool your beads in than a piece of fiber blanket, because it excludes more air around the bead when it is cooling.

The very best thing you can do is try to buy a kiln with a digital controller. With the digital controller, you wil be able to properly anneal your beads. On a kiln with an analog control (so called 'infinite switch') you will be able to at least cool the beads without them cracking, but most likely not annealed at the right rate of cooling.