New Custer

I just opened a new bag of Custer Feldspar. My last 50 lb bag was about 10 years old - so I recomputed the glazes
mashiko_ZJ_0 and mashiko_ZJ_1, with essentially the same empirical formula according to
Ron Roy's analysis, and fired them on ~3 inch diameter bowls.

As the glazes have new recipes they got new names - respectively mashiko_ZJ_0_NN, and mashiko_ZJ_1_NN. They are shown below.

For reference, I also show pictures of the original glazes, same clay body, same firing protocol, same all other ingredients other than Custer Feldspar.

In all cases the glaze is thinner on the outside of the bowl.

cone 10 oxidation

Firing profile

Up Fire profile

150 deg F an hour to 250 deg F

400 deg F an hour to 2050 deg F

120 deg F an hour to 2250 deg F

60 deg F an hour to 2310 deg F with a hold of 20 minutes at 2310 deg F

Down Fire Profile

A half hour hold at 1750 deg F

A three hour hold at 1700 deg F

slow downfire at 25 deg F an hour in the interval 1700 deg F to 1650 deg F

A one hour hold at 1650 deg F

Clay body is a grolleg porcelain from Tacoma Clay Art Center.