Wednesday, December 9, 2009
Mattie, my youngest son, at age 4.
We are usually pretty partial to curls around here. They are rather appealing on small boys, at least. Sculptors from the turn of the last century must have thought so, too, because Brookgreen Garden is filled with sculptures of curly-haired toddlers.
Newly pressed tile (left) and partially dry, curling tile (right)
Curling is not so appealing on tiles, though. I'd almost forgotten that curling was the bane of many tilemaker's existence. I know the rules for avoiding curling, of course. Don't make overly thin tiles. Don't make rectangles. Don't have large differences in thicknesses.
I had skirted the edges of those rules often enough with no ill effect, that I guess it was only natural that I would forget them. Now I am paying the price with rows of "Inspire" tiles that look like potato chips.
So it's time for some quick problem solving. I think my problem is the big difference in depth at the horse's shoulder. (At least, since I broke all the rules rather blatantly, I think that's the one doing the most harm.) I have tried some of the normal approaches to the problem, like covering the newly made tiles so they dry slowly, but I'm not sure any of them are going to fix the issue completely.
I originally thought that I might do better press-molding the tiles since my early attempts at those were relatively flat, but as the above picture shows even those are warping a bit. I might still have to make this work, since most of my production molds haven't dried enough for slipcasting. Press-molding allows me to get more pieces from a given mold each day, and I can use the molds a little sooner. The downside is that the moist clay used for this doesn't capture the detail quite as well as the slip. Of course, these guys are getting an art glaze so I suspect the slight difference won't matter compared to the loss from the glaze.
But for the long term, I need to work out the curling problem for the slipcast pieces. I have reconfigured the pour holes for the molds. I think that being able to drain the thickest part - so the shoulder area is semi-hollow - might fix the uneven drying.
On the upside, I was able to fire one imperfect bisque to see if I calculated the shrinkage correctly. Sure enough, I have a 2.5 x 3.5 trading card.
I can also use my imperfect tiles to test glaze colors. It's just a few weeks away and I still haven't decided what color these guys will be!
The other positive is that with all the frustration with curling, tackling some of the more difficult passages in the horse color book has seemed downright inviting. Yesterday I was able to knock out the section on palomino "Arabians". I still have a long way to go, but I've begun to hope that I might make my BreyerFest 2010 publication deadline.
at 11:18 AM