As a self taught potter I have found out most things the hard way. Layering glazes is one of the techniques I have tried, failed, done some more reading, and tried again with a greater degree of success.
Problems with layering glazes – cracking and bubbling
After seeing the results from other potters’ layered glazes I thought I would try it myself. My attempts have resulted in very thick layers of glaze. Sometimes I got cracking or major bubbles in the glaze when it dried on the pot.
For some reason I’d always assumed it would be better to dry the first glaze before adding a second. This was largely because I didn’t have any glaze tongs. Working with layered glazes while holding pots in my hands led to messy finishes. The glaze application on the pots above was so bad I cleaned them off and did some research.
How to achieve better layered glazes
I was surprised to read that most people actually do two glaze layers straight after each other. By adding the second layer while the pot is still wet one can achieve the optimal overall glaze thickness. After treating myself to some glaze tongs, layering glazes has become much easier. I simply dip in the first glaze and leave a few minutes to dry. Once the sheen has gone and it’s touch dry I dip in the second glaze. The next day I rub over the tong marks and wipe clean the base of the pot.
My forum question was also about the specific gravity – how watery the glaze should be when layering. Most of the responses on there suggested no adjustment to the consistency. I did try thinning out the glaze a little and tested on some old tumblers I had laying around. In the end it seemed my standard glaze consistency worked best. For these glazes it’s around 45 on my hydrometer.
I forgot to take a picture before firing the cups with layers added straight after each other. The glaze looked a lot smoother without any cracks and a good thickness overall.
Layered glaze results
Before glazing these cups and saucers I did a few glaze tests with egg cups. I’ve read that it’s best to use a matt glaze over a gloss glaze. I only did a few tests but found that a gloss over gloss worked better for me. The cups have a very dark bluey black gloss under a semi clear cream gloss.