Updated: Aug 7
As terrible as lock-down was, it seemed to throw most people into a loop. During my time with Simon, I was tasked with making air release tile molds made out of hydrostone (gypsum cement). I had gotten quite efficient at making them and the simple rectangular shapes weren't terribly complex. There was a bit of a learning curve in understanding how to handle and respond to hydrostone in its different stages. During lockdown, I made around 3 or 4 due to errors and learning curves. The mistakes may or may not have been obvious to those who understand mold making but they were crucial to my learning and I am grateful for Simon's patience.
Sometime after the last tile mold I made, Simon suggested that I make an air-release plate mold. I had fussed around with plate molds before with little to no success. So naturally, going from bisque mold to air-release plate mold seemed like the obvious next step...I put this project off for a while. I was nervous about wasting a whole lot of hydrostone and rationalized making enough pots for the anagama firing coming up in July. Some unimportant amount of time later, I decided to bite the bullet and give it a go. Below is the master plate form I made with the intention of casting. I first threw a dome shape then added slabs and more clay on top of that for the feet.
Its unfortunate that I only have images of my process from an old Instagram story. Its better than nothing. I applied 3 coats of Murphy's oil to my master mold then built up clay dams just a little higher than the feet of the plate. I had prepped a circular cut out of chicken wire with a spiral of woven tubing tied down. The male-end of the air-release fitting was also prepped. After laying down the chicken wire on top of the dam, I built up the dam another 2-3 inches.
Once prepped, I measured out the hydrostone and water, mixed, waited, then poured. There's a funny story in there where I was short the amount of materials needed and paniced, calling for Simon to measure out more hydrostone and water before the first layer set. Long story short, it worked. After waiting for it to set, I hooked it up to de-water it so the mold could have its 'air-release' properties.
Below is one of the many plates that came out of this mold after cleaning and messing around with surface design and texture. The mold isn't pretty but it works like a charm.