Microwave shelf/plate

A friend brought a chunk of shelf over this morning.

Puntied up to a 10mm rod and proceeded to gather up and implode some dots.

I couldn't believe how soupy it was, flows really easily and appears compatible with boro colours.

He's tried attaching regular boro clear rod as a bail for the pendant but they cracked off after a short while, maybe because he's only flame annealing then bringing them over the river to me to kiln anneal later.

Anyone have experience of this material? Is it a 'kind' of boro, pyrex, or?

being a microwave shelf one would assume it is some kind of boro, but if the bails break off he's either attaching them incorrectly, not flame annealing them properly, touching them with cold tweezers after flame annealing them or it's not particularly compatible (although if the colours are stable one would assume that compatability is not so much of an issue). back in the 60s and 70s there was a company in Australia manufacturing boro rod and tubing but they closed down in the mid 70s. I was lucky to get my hands on a little bit in the early 90s and it was perfectly compatible with Duran, but worked more like soda glass ("soupy" as you would say). It made perfect joins. I've been keeping my eye out for some more, I'm sure someone, somewhere has a stash of it in their shed.
another thing you can try is clear glass oven ware, that's boro too, and usually quite chunky.

Alot of the boro cookware is not 33 coe. Most boro comes in 33coe but you can order other coe boro (if memory seves me) and im almost possative the cooking ware is not 33 coe. ( as every time I tried it, it always cracked.)

It's 55 COE boro.

Thanks very much, always learning.

I have seen stepped seals done to use pyrex cook ware lids as feet for sculptures. But yeah it is not 33