STAINLESS STEEL MOLD PREP
Posted On March 23, 2019
This was fun! A customer came in with a stainless bowl that she had slump a thick piece of glass over. It stuck! She broke the ruined bowl off, but a very thin layer of glass remained on the mold. That prompted a discussion on how to get the rest of the glass off the mold and why it stuck anyway.
First to get it off. She was first going to try fusing it off and if that did not work, she was going to sandblast the stainless. One or the other should work.
Then she said she posted a picture of it on a facebook fusing group and prompted a discussion about prep of the stainless. Here is the surprise! Some people do not prep it AT ALL!
I went to Facebooks Fusing 101: Any and Everything you Wanted to Know But Where Afraid to Ask. I said “Recently I heard that some people do not kiln wash stainless molds. I would be interested to hear what people think of this.”
There were some differences of opinion to be sure..
- Cover with fiber paper or ZYP
- Spray with Boron Nitride (ZYP)
- If you use ZYP you rarely have to do it again
- I don’t use anything on stainless steel. As long as the glass is NOT an opal glass in contact with stainless steel and it is good quality, it is fine. You get a real shiny finish on the surface in contact with the stainless steel.
- It is minimal work to use a barrier. I would rather be sure instead of concerned.
My own fusing teacher was emphatic about using something. She suggested Slide because it is cheaper than most boron nitride products and it is easier than kiln washing.
More inexpensive, but more labor, is to use kiln wash. The problem is that it slides off the mold easily. Here is the trick. Wash the mold with alcohol and then heat it in your kiln to 1200 degrees F for about ½ hour. Cool it. Then heat again to just under 500 degrees F and brush or spray on the wash in thin even coats. Allow the coating to dry completely between each application. Coat it until covered. After the first time this is done (and it does last a long time) we will just coat it put it on top of a hot kiln. Seems to work fine.