I started a similar topic "Non Runny Ash Glaze" see below, and have tried three different glazes, For two of them I used ashes sieved thru 40 mesh but for the third I used ashes put thru an 80 mesh sieve. The trials with 40 mesh ashes were too granular for me but the 80 mesh ashes gave an acceptable result. For the latter test I used a glaze recipe supplied by AtomicAxe, it was called SU Standing Bear (see "Non Runny Ash Glaze"), and it gave a nice smooth glossy.finish. The two glazes used with the 40 mesh ashes would probably be more acceptable for me if I tried 80 mesh. They were the Black Friday glaze that S. Dean referred you to; a matte finish, and a variation of C. Harris Tenmoku: Nepheline Syenite 18.6, Gerstley Borate 8.5, Dolomite 9.3, Talc 9.3, Ball clay 18.6, Silica 28.2, Bone Ash 7.5. I replaced the Red Iron Oxide, called for in the original recipe, with 12% Black Mason Stain (6600) and added 1% CMC to improve brushability. I will try to send photographs to the forum as soon as the mugs have finished cooling (I cheated and looked a little early). Good luck, Joan Klotz.
I have an L&L kiln so maybe your envirovent works differently than mine. For mine, aluminum ducting leads from the bottom of the kiln to the vent motor. The exhaust end of the vent motor is situated so that fumes are vented outside my studio. I have had my kiln for over 10 years but twice during that time I have had to replace the aluminum ducting leading from the kiln to the vent motor because of cracks/holes developing in the duct. Could this be the case with your system? Joan Klotz.
Thanks Audra, I'll make up a test batch of the SU Standing Bear glaze today. Like Jeff Zamek's black lab, my husband was very fond of wearing black so I'll add 12% 6600 Mason stain. It has been an unpleasantly busy 6 weeks since my husband passed with little time for clay. I have managed to throw and bisque fire about 30 mugs, and the future looks clearer, so I'll test fire the three glazes I have decided to try very soon even tho my kiln will be largely empty. Not ecologically sound, but none of my friends have stuff to add to the load. Unless the results are totally embarrassing I'll post pictures, Joan Klotz.