DeBorah Goletz on thu 24 aug 00
One of my kilns was inherited from Parsons School of Design where it was
occasionally splashed/misted with dirty liquid from leaky plumbing pipes.
The kiln is about 10 years old and now resides in my (leak free) studio
where I brushed the corroded metal clean and rewired it - but when I fired
(only to bisque), I got significant amounts of new corrosion: in the
perforated metal housings which hold the switch boxes away from the kiln, on
the lid hinge, and even on the brick top of the lid itself and the outer
edge of the top ring - where brick meets sleeve (which is not corroded).
The brick lid is blackened and puckers up at the vent holes drilled for the
environvent. The underside of the lid and inside walls look okay, but I
worry that the damage might weaken the lid. Has anyone ever encountered
this and what did you do to stop the corrosion? I'm considering painting
kiln wash on the top of the lid and aluminum paint on the metal parts.
Best,
DeBorah Goletz
vince pitelka on fri 25 aug 00
> The brick lid is blackened and puckers up at the vent holes drilled for
the
> environvent. The underside of the lid and inside walls look okay, but I
> worry that the damage might weaken the lid. Has anyone ever encountered
> this and what did you do to stop the corrosion? I'm considering painting
> kiln wash on the top of the lid and aluminum paint on the metal parts.
Deborah -
I'm not sure what the blackening color is. I have not seen that. If you
were bisque-firing something with a lot of organics, newspaper, cardboard,
wood, etc., it could have produced enough smoke to result in the blackening.
But every bisque firing produces sulfer dioxide gas, which in exterior
atmosphere produces a weak sulfuric acid, which is responsible for the
corrosion. Some of the best kilns use more stainless steel, which is immune
to the corrosion. Otherwise you just have to clean and paint the
non-stainless metal surfaces on a regular basis. Use high-heat paint,
available from any auto parts store. The brick itself is not corroding.
What you are seeing is a deposit left by the sulfur dioxide, and you can
just brush it off periodically. It should not hurt the brick.
Good luck -
- Vince
Vince Pitelka
Home - vpitelka@dekalb.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
http://www.craftcenter.tntech.edu/
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