Scrape, Prime, Bake, Repeat: The Shelf Preparation Cycle

As I mentioned in the 2024 Studio Tour, I go through a lot of kiln shelves. Why, and how many are we really talking?

Each time I put a piece of glass in the kiln, it goes on a stone shelf. I paint the shelf with a wet mixture of clay and minerals that keeps the glass from sticking to the shelf when it gets hot. This coating is only good for one trip through the kiln, after which the shelf must be scraped with a razor, sanded with a drywall sanding screen to remove recalcitrant bits of shelf primer, vacuumed, painted with six coats of new shelf primer, and fired to a low temperature in the kiln to dry it. The scrape-prime-dry cycle takes 4-6 hours depending on the ambient temperature in the studio.

Each finished piece of artwork I create uses 5 or more shelves as I fire and shape the intermediate components before melting them all together. Sometimes I feel like most of what I do is scraping and priming shelves! And this is why I buy the powder for mixing up the shelf primer in 5 lb buckets.