Here is a quick lineup photo of some of the cups I just fired in the Blaauw.
What the photo doesn’t show, is that 6 of these cups have glaze defects, and will need to be refired. But I don’t think those defects have anything to do with being fired in gas instead of electric. That is an application problem…the downside to pushing work into a kiln late. I should know better by now. Anyways, the side by side comparison of the clay and glazes shows that the clay has a cooler color. See below…
So that answers my question, kind of. The Blaauw combustion works by percentage. Default is 100%. The reduction firings we ran in the other Blaauw over in the pottery were at 83%. I just ran this kiln at 120%. From emailing with Gerard, the next firing I’m going to up that percentage to 140%. This is the type of control and precision that I feel makes the Blaauw different from other kilns.
The difference in the color of the glazes was negligible. My conclusion is that when I can make enough pots that would equal one and half large skutt kiln loads, then its worth it to fire the Blaauw. However, since my work is now revolving around making sets rather than singles, I won’t be able to complete a set with pots that some were fired in electric and others fired with gas. Overall, the difference in the clay and glazes between electric and gas is just a little different, I don’t think one is really any better than the other. I’m curious if 140% will warm up the color of the clay a little. This isn’t the first time that running a test has led me to do more testing.