Here are the new stoke hole plugs (along with a couple of larger pots that still have a lot of drying to do). I decided to keep the same shape as last time. The clay is incredibly groggy (well groggy, and "saw dusty")when compared to the last batch, so I'm hoping they won't warp much at all.
As for the recipe I ended up slaking down forty pounds of the old clay (50/50 EPK kyanite) then added ten more pounds of EPK (we didn't have any fire clay at the studio.... go figure) along with ten pounds of coarse grog. I then tried to estimate out and add one third sawdust by volume. After this mix dried enough to use I found it pretty lacking in plasticity, to the point I was having trouble just keeping together to wedge. So I added a little bit of wet sagger clay from last cycle, maybe about a third. So the math gets a little fuzzy and convoluted, but as far as I figure the end recipe looks something like this:
add 2/9ths sawdust by volume.
We'll see how this works. I can tell you one thing though, it's a little painful to throw. I ended up pounding the lump of "clay" into a ring with a flat base instead of opening it, then centering and throwing exclusively with a sponge in one hand and a rib in the other (using almost no water as per Alex's suggestion). Hopefully it will work well.
You can also see in the picture I used a little bit of the clay to make a plug for our blow hole in the first chamber (which we cast into the key using a plastic cup. Our first firing we left this open while firing the second chamber and ended up cooling the first chamber a little more quickly than we would have liked (we also had a little bit of dunting from pots underneath the blow hole). So we'll certainly close it up tight this time around.
that's all for now, just finishing up some pots and trying to figure out what needs to be done as far as kiln prep goes.