Pate de Verre - Ballotini -

Pate de Verre - Ballotini

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Joe Pfeifer
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Joined: Thu May 27, 2010 9:55 pm

Pate de Verre - Ballotini

Postby Joe Pfeifer » Sun Dec 07, 2014 2:04 am

I have a large amount of extra fine glass balls ballotini. It's small enough to be described as a powder. I would like to do a little experimentation using it for the clear base with which to mix powder colors for Pate de Verre.

If I was to take "any" powdered glasses, i.e. fritted bottle glass, or my ballotini, crushed float, Bullseye, System 96 or even lead crystal and use as a clear base. Can I then mix any of these base powders with any color, any C.O.E. from Bullseye, or Kugler, etc? This is of course if I cast the entire piece with one "mixture".

For example, 90% ballotini and 10% powdered Bullseye?

My question is, If I mix with 20% 0r 30% Bullseye, for darker colors, can I have different ratio mixes within the same piece without cracking? (I don't know what my ballotini C.O.E is measured at).

When I watched the Higuchi video, it showed them fritting and grinding furnace glass (96), then mixing it with bullseye color powder (90). I heard from one of their students they use Kugler (96) in their own studio. They had all sorts of mixtures and ratios they seemed to be mixing for the same piece of work.

If your using powder, anything goes?

Kevin Midgley
Posts: 709
Joined: Mon Mar 10, 2003 11:36 am
Location: Tofino, British Columbia, Canada

Re: Pate de Verre - Ballotini

Postby Kevin Midgley » Sun Dec 07, 2014 1:55 pm

The ballontini I have right now when fired turns an ugly gray.
Well that is when it fires properly.
Ballontini by definition are round and that shape is the problem,
I have not tried to thoroughly mix the ballontini with other glasses but if you get a mixture hot enough it is possible to come up with an unknown COE throughout the piece.
I would not try to mix different areas with different amounts of colourant material and expect it to work as in stay together over a long period of time without cracking.
That being said you are formulating when you do the above idea, your own glass so it should in theory be compatible with itself..... but maybe not. Only your experience with your mixtures in your kilns and your molds will be important.
the biggest problem I've come across is the insulative property of the ballontini themselves. Unlike crushed material with its random shapes and edges, the ballontini automatically have insulating air pockets between each ball. The last time I tried using them I ended up firing for a hugely long time at a temperature I calculated would work in my kilns and I got nice exteriors with unmelted interiors.
So yes you could mix the colourant into the glass and see what comes of it, knowing the ballentin's natural colour is devitrified gray probably anything is better than that.
Once again, there's a reason to stick with Bullseye as in Pate de Verre it will not flow as readily as 96 and thus you have less risk of unwanted colour movement. The ballontini in that respect is a perfect material as it won't flow easily at all.

Bert Weiss
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Joined: Tue Mar 11, 2003 12:06 am
Location: Chatham NH

Re: Pate de Verre - Ballotini

Postby Bert Weiss » Sun Dec 07, 2014 6:01 pm

I can picture mixing frits of different compatibilities both working or having trouble. Each glass is busy pushing or pulling as the temperatures change, whether from 70º to 80º or from room temperature to the strain point. If the glasses are mixed more or less homogeneously, these stresses could balance out. If there are big areas of one next to big areas of the other, I picture cracking happening, unless you have higher COE glass encased in lower COE glass. In that case the glass is put in a state of compression and is stronger.

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