fter testing 10 or so recipes off the internet for this type of iron-based red glaze over the past half year, I finally got the results I’ve been seeking. The red color comes from the crystallization of the iron during the cooling of the kiln, which is the tricky part. The general consensus on the internet recommended a hold at a temp between 1600 to 1650 degrees, but I found I needed a hold at 1800 degrees to produce any red. Here it is on a coffee-maker for a friend-> I wanted this to be one of my new Bouja glazes for last fall’s fundraiser, but it didn’t work out in time, so it will be one of the beautiful new glaze offerings this fall. And here’s the recipe and the firing schedule that I ended up with:
Touchtone Red31 Gillespie Borate 30 Flint/Silica 20 Custer Feldspar 14 Talc 5 Edgar Plastic Kaolin 15 Spanish Iron Oxide 4 Bone Ash
Firing Schedule:200 degrees an hour to 1100 300 degrees an hour to 1975 108 degrees an hour to 2175 with a 15 minute hold cool at 500 degrees an hour to 1800 an hold for 60 min remainder cooled naturally Note: You need the proper thickness to get the reds to show, where it is too think it is blackish, and where it is too thick it acquires this scummy gray green speckling over top of the red color. I would describe the thickness as normal or average application. Sorry, I don’t have a specific density.