Tin/chrome pink earthenware glaze
I got a new book recently, Colour in Glazes by Linda Bloomfield and I’m finally getting some glaze recipes to use for earthenware that don’t rely on commercial stains.
This glaze recipe relies on an interesting reaction between tin, chrome and whiting (calcium carbonate). Basically, if tin and chrome are in a glaze, it starts off green, and as you add whiting, it turns pink. For these test tiles I used 10%, 15% and 20% whiting. Obviously even 10% was enough to turn it pink and I have done some more test tiles with far less whiting.
I’m hoping to get 2 glazes, 1 green and 1 pink, that can be combined together to get nice gradients.
I actually had 2 other variables as well. The recipe just said calcium borate frit, and I had 3 different ones which might have been appropriate. And it also said chrome oxide as the source of chrome, but I only have the tiniest amount of that. I had lots of iron chromate though, so I tried that as well.
Recipe
39 Calcium borate frit (3124, 3271, 4108) 27 Soda feldspar 23 Silica 6 Kaolin 5 Tin oxide +0.1 Chrome oxide/iron chromate + Whiting
Test Grid
I decided the best ones were the 3 in the top picture - AB, AZ and AK. They were the ones with the best surface and the least pitting. Though I think it was the excessive whiting that caused the pitting.
AZ was the one I decided to do further tests with. I also did these tests on stoneware clay, because my earthenware test tiles weren’t ready, but my further tests were done on 3 different types of earthenware clay.
