Tuesday, October 30, 2012

Failure is a Chance for Learning

by Janet Alexander
Technical Advisor

I read somewhere or was told that painting the stainless steel container used for firing the sterling silver clay would keep it from flaking, so I set out to test the idea.

I took a brand new clean stainless steel container and lid and painted them with high-heat paint used for coating rifle barrels. After it dried, I baked it at 300 degrees F for several hours to cure the paint.

Unpainted Container

Painted Container

Next, the test to see if it flaked or not.

I fired it at 1500 degrees for 30 minutes with coconut carbon and some sterling silver rings inside. I removed it from the kiln while it was still hot. For the first minute or two nothing happened. But then all of the sudden paint started flying off across the lid like stacked dominoes falling over. It was very interesting to watch the paint flake off in a line going around the lid. Then as the bottom started cooling the paint on each corner flaked off. Watching this, I decided that the reason the paint flaked is because the metal was contracting while cooling, forcing the paint off the surface. There was less metal flaking, but as I used the container over and over again the metal started flaking also.

So, back to square one. But I do know now that paint doesn't work. A friend told me to try coating it with kiln wash. Maybe I will try that next?

More sterling sliver clay is on he way for my testing, so keep an eye out for the November test and have fun claying around!


Babette said...

You're a hoot, Janet. You try things nobody else would have even thought of!! ... and good for us!

Janet Alexander said...

Thanks Babette, I tend to ask too many questions sometimes and pay for it later! I just a curious artist.