Fusing an element that requires fire polishing

Cliff Swanson · Post by **Cliff Swanson** » Tue Mar 18, 2003 10:38 am

I have a piece of black irid that I sandblasted, fire polished, and will incorporate into a design layout. I wanted to fire polish this tile separately before fusing it; but just for future reference, is there any reason why the fire polishing of an unpolished component couldn't just happen as a consequence of the full fuse, thereby saving on the number of firings?

BTW, I blasted this black irid with SiC and the fire polished surface is shiney black, not hazey. Did I just luck out?

TIA,

Cliff

Tim Lewis · Post by **Tim Lewis** » Tue Mar 18, 2003 11:22 am

Cliff, sandblasted black has a tendency to haze over on the second firing and especially if it isn't cleaned well. A higher temp firing and crash-cooling will help negate some of that but....

The general rule of thumb is to keep your your firings fewer and lower temp for most situations. With too much cooking you can also change the COE of some of the glasses so that they no longer fit as well. That doesn't mean that some people aren't successful with more cooking, it just means that less cooking is generally better (cheaper & less time too).

Let us know how it goes.

Tony Smith · Post by **Tony Smith** » Tue Mar 18, 2003 1:29 pm

Cliff, sandblasted black has a tendency to haze over on the second firing and especially if it isn't cleaned well.

Tim, I disagree with this statement emphatically. I sandblast black all the time and rarely have problems with hazing unless I use thinfire during the first firing after sandblasting. I wash with only running water after blasting and fire to a matte finish during slumping and to a high gloss during a full fuse and just have not experienced it. Is there something else that you are doing that might be causing the haze?

Tony

ps: the piece below went through 6 firings... three of them after sandblasting.