Topic: Lovely Mdina? iridescent turned over rim bowl.

[AndyD]

Interesting, I hadn't thought that the Boffos may have taken the method with them from Whitefriars.

I do have a bottle and stopper by the IOW studio with the same bubbles.  I think it's more prevalent in IOW glass but again it has so many.

I do love the bubbles and always look out for pieces with them.

[chopin-liszt]

I strongly suspect bubbles in glass predate Wfs, by a thousand odd years.
Getting rid of them was a bigger problem with early recipes than adding them.
I think, in Mdina, they can arise from the chlorine gas being released from silver chloride, and I've heard of potato peelings and even just plain carbon being dumped in a batch, to produce bubbles.

[AndyD]

Yes I'm sure you are right about them predating whitefriars but I didn't know if they were added for effect or were there due to a problem or mistake.

That's why I wondered if they were a sign of a certain date of production and were later removed due to perfecting the process.  I assume the IOW bubbles were put in as by then they would have known how to keep them out.

[chopin-liszt]

  I think it's less that they are "put in" and more of "they're allowed to occur".
Tiny bits of air can get trapped along with the coloured glass powder picked up on a gather, when making the decor, and when heated, they will expand.

[AndyD]

Thanks, that's interesting. So much to learn.

 

[chopin-liszt]

The learning never stops. That's what makes glass so interesting.
Do try to go and watch it being done. It's absolutely fascinating. The more you learn, the better able you are to work out what's easy to do and what's difficult, and you can judge the quality of something a bit better if you know about that.

I used to think bubbles had to be "put in" too, and I will never forget the very early thread here when we discovered controlled bubbles got "put in" using a mould with prickles in it, to make tiny holes around the gather before capturing them in the casing.

We'd been imagining somebody with a special needle and syringe, putting each tiny one in, one at a time.

[AndyD]

I went once to see Timothy Harris work and it is amazing to watch the procceses. He is one of the best and we will go again when time allows.

I'm reading a lot but handling as many pieces as possible is one of the best ways to learn for me.

   Andy