Problem with Clear???

Chris Haussler · #1 2012-08-15, 6:24pm

Has anybody out there had trouble with Effetre Super Clear causing some dichroic glass to loose its' sparkle?

I have used dichroic glass the last couple of years in marbles (you know the galaxy swirl type). I have ordered from both Arrow Springs and Frantz. Most of the pieces of dichroic have been fired once but I have one piece that is not. Up until about two months ago, I did not have a problem with losing the sparkle. Using an oxidizing flame, keeping the coating facing away from the flame, etc. Once I started using the latest batch of Effetre Super Clear I got from Frantz, I started having problems with the dichroic that is not fired. I build a gather, warm the piece of dichroic in the outer reaches of the flame, and as soon as I touch the gather, the sparkle goes away.

The coating is intact and sparkly until the moment of contact with the gather. I have tried letting the gather cool just a touch to no avail. I have checked that I am not accidentally heating the wrong side of the dichroic chunk. The dichroic glass that has been fired does not loose its sparkle.

Has anyone had a similar experience? Any suggestions?

Three Muses Glass · #2 2012-08-15, 6:57pm

I think it's not the clear. Prefiring your dichro would be the best way to go. I put strips face down on a kilnwashed kiln shelf and fire to 1300-1350 for about 15 minutes. Since the kiln I use is brick, I don't anneal and just shut the kiln off. This glass will be annealed later after use anyway. It really does stabilize the coating nicely.
Alternatively, you could try folding your unfired dichro. Heat the non-coated side as you've been doing and fold it over itself, sealing the coating inside. It works but I have gotten scum from the sides and prefer prefired dichro.

Lyssa · #3 2012-08-16, 2:57pm

All I know is that the Effetre super clear I have is not, in fact, super clear. It's covered in lengthwise scratches and bubbles. I hate pickling my glass, but I guess I will have to.

Chris Haussler · #4 2012-08-16, 6:06pm

I have used the dichro as it is for the last year and a half with no issues so I am not convinced that it is the whole problem. Thank you for telling me how you fire your dichro. I did not know the procedure or firing schedule.

The Super Clear I have been using also has a lot of bubbles and scratches. I pickled it when I got it but it is still scummier than the regular clear that I used prior to my problems. I have to regularly skim the scum off the marbles now. That is something I did not have to do as much before.

I just bought a pound of the VS clear offered by Frantz to give that variety a try. I suppose time will tell. I may have a couple of pounds of clear that I can use as a core for other colors.