Clay Testing Pt. 3 (Improvement)
Next tests 10/23
After another round of both excitement and confusion I enter another stage of reformulation. The results of my test for round 2 were without a doubt better than the first ones but there is still a lot of room for improvement. So for the improvement ill list my thoughts on the bases of what I’m gonna do next.
From left to right : Test clay with VT kaolin and satin glaze, Test clay with PA clay and satin glaze, Test clay with satin glaze, Test clay
Reduce feldspar
I have a feeling like the bodies may have too much feldspar. Looking at them together they all have very similar color and similar bloating despite varying amounts of Unami clay (5a) only having 5%. Maybe the trouble of the feldspar clumping too much is actually an issue here
Push iron content down
the more obvious would still be too high iron and overfiring. The bloating consistency is very consistent with all bodies which is actually making me think a bit. I had tested (H) tests once previously but if I remember correctly there weren’t many bloats which is true. That test had no feldspar in it. It did have dunting issues but maybe I can change the feldspar content along with the iron to bring the firing temp up again.
Try sieving it
based of the previous change maybe sieving the slurry could break any clumps up. Since I’ve been mixing so quickly maybe it could still be a technical error. Definitely a last stitch effort. Probably only try one test mixed with and without sieving.
Notes and General Thoughts
I’m still a bit stumped honestly. I can’t change the temperature at all which was highly recommended from both friends and research so far. I also don’t know enough about the chemistry behind these materials to fully understand how to analyze them. A lot of this is just a bunch of shots on the dark. There’s definitely a semi clear goal in mind but the direction I need to take to get there seems so foggy. Just like now there are so many different variables to try and test. Some seem to be more plausible than others but that doesn’t mean it’ll be fixed.
I have to keep in mind that even though I didn’t reach the goal this run doesn’t mean there wasn’t progress. Most tests were bloated significantly less as well as a reduction in the surface sheen telling me the clay was fired closer to its desired temperature. For shits and giggles I might add alumina hydrate just to see if that helps any. Hope that doesn’t encourage dunting.
Also after talking to my boss/ mentor, I was given advice to try increasing the ball clay. Im thinking another way to increase the maturing temperature of the recipe. In addition it should also make the clay nicer to throw with. Most of the recipes have been fine but there have been small tendencies to be a little short, or in other words, causes cracks and tares in the walls of pots while throwing because the clay doesn’t have the strength to hold its self together.
It may also be good to not only research other refractory materials but also make test strips of the individual materials themselves (hawthorn, newmans red, foundry hill crème)