Second Round

I don't really have suitable pots for these tests [that's why I'm firing a bisc kiln today] but used a vase for a bunch of tests.I mixed up a second test glaze and painted on increasingly-thick patches of each glaze,thinner at the bottom of the vase,reaching 3-4mm.at the top.I also reduced the top temp. to 1275 degrees [cone 10] and shortened the supposedly-critical last part of the firing.
The results tell me that thicker layers still go volcanic [bottom right picture],while moderate thicknesses do the job pretty well.The second glaze seems to work quite well,with orange iron bubbles in a brown glaze,but I'm more interested in finding a black oil-spot.Mind you,the first glaze is black because of iron and cobalt additions,while the second glaze only has iron,so,obviously,I'll try adding some cobalt [and/or manganese] to the test batch....
We are still here in Safed,safe and well.Helen has just gone on a brief exploratory walkabout,ostensibly to look for challah for Shabbat,but more,by her admission,to check out the town.I have not been outside the house for over a week,which is a long time even for me.Helen is back,so Shabbat Shalom....