The project is/was intended as a mixed media woven glass wall-hanging. The weave-y noodles are BE Aventurine Blue and Salmon Pink. They are shaped over a high quality 316SS custom mold, designed not to spall or flake up to 1600 degrees. This particular  mold has been used about 10 times and has a lovely oxidation but otherwise perfect condition.

NOTE: Fired in Denver CS60 with mold sitting directly on Dyson shelf. My standard schedule is ramping up at 350 dph to 1380, hold 5 and allow to cool to RT. No scheduled anneal is necessary on this first step because the Denver cools so slowly.

Each time I used SLIDE HI-TEMP 1800 mold release, and as the name states can be used up to 1800. Between runs, the molds are vacuumed and then wiped clean with a cloth and fresh SLIDE applied. The  aerosol can states that materials can be cleaned up post-firing with isopropyl alcohol.Over the ten identical runs (other than different colors of glass) there have been mixed results; slightly worsening each time. The first few times the glass slumped properly and the slight hazy on the back of the glass did indeed wipe away with a swipe of alcohol. Those runs used a mix of black/clear, assorted greens and blues.  

The next few runs used a lot of transparent dark colors like cobalt and garnet. The white haze left on the back of each noodle would NOT wipe or scrub away with alcohol. Soaks in hot soapy water did not remove all the haze. I treated these noodles the same as if I had stuck-on kiln wash, rather than Boron Nitride. An overnight soak in a bath of vinegar worked. Finally I resorted to just sandblasting the backs of the noodles for speed.

THEN it happened… same mold, same can of SLIDE freshly applied, same schedule… different glass….

Cracked the kiln lid 1/2 inch at 300 – my standard procedure – walked out of the room for 5 minutes and returned to the sound of Jiffy Pop coming from the kiln. A quick peek shows the Salmon Pink is breaking up and spitting glass bits all over.

 After cooling I found the Aventurine Blue had also stuck slightly, and when lifting away found glass pits on the backside where the glass had been pulled away – even from the ones that were NOT stuck.

Surprisingly there is no aventurine glass stuck to the mold. The bits just swept away easily. The Salmon is stuck in areas and underneath each Salmon strip the mold is pitted and damaged.

Now I’m stuck with a LOT of questions….

  • Is there a slow degradation of the SS mold that’s not visibly apparent?
  • With all factors being the same, why is the BN progressively harder to remove with each run?
  • Why did the Salmon stick so badly?
  • Does whatever makes “aventurine” have a protective effect as mica would?
  • Why didn’t I just use the darn kiln wash to begin with?