Sanding Pots, Part 2
My April 10, 2014 blog focused on how I sand pots when they're greenware and after they're fired to cone 10. Since then, I've changed things a bit and wanted to share that with you. In the earlier blog, I mentioned that I used a small piece of kiln shelf to sand down large sections of exposed clay on pots that had been fired to cone 10. I don't do that anymore. I changed my technique for two main reasons: first, because I kept chipping the edges of pots when using the piece of kiln shelf, and second, because I began experimenting with using just silicon carbide sand paper. What I'm doing now is to start sanding with a fairly coarse silicon carbide sand paper, 120, move up to 320, then 400, and finally 600 if I want it to be really smooth. I don't tend to use the 600 on clays with lots of grog like Soldate or Rod's Bod, but I certainly use it on smoother stoneware clays like Death Valley and Black Mountain. This is a technique I especially like to use on bowls that are unglazed on the outside. I also use 320 sand paper on the rims that are unglazed and on other edges that seem overly coarse. It makes the surface smooth without marring the surface of the glaze.
I also pay more attention now to how even my bases are and use sanding techniques to even them out. A few months ago I was setting up for a show and was surprised at how many of my pots were rocking around on their bases. Determined to do better than that, I began finding the high spots on the bases of greenware and sanding them down. This didn't work very well because I was never able to get the whole surface even. So I began taking pots out to the smooth concrete on the patio and pressing them gently down while rotating them. This solved one problem but created another: it evened the base quickly because it was removing material all the way around, but it often chipped the base. I began looking around for something else to use that wouldn't be so aggressive and found in time that the textured surface of Amaco plastic bats works well. I'll just place one on the grass and press down gently near the base of the pot while rotating it. I suppose I could put the bat on the wheel and spin it while holding the pot on it, but I prefer this way because it seems to give me greater control. Some people use diamond embedded disks to sand the bottoms of their pots after a glaze firing, but I haven't tried this yet. I've found that if I even out the bases of my greenware, the bases of most of my pots are even after the glaze firing.
I hope this blog will be encouraging to potters, especially beginning potters, and a source of helpful information and comment.