Hi, Bryan, some time has past, have you solved your issue?
I found this discussion today since I am experiencing very similar issues.
I'm using already prepared stoneware slip from my pottery shop to produce cups without handles: https://www.potterypassion.com/products/0208-casting-body
And around 90 % of my cups appears warped after glazing ( fire at 2192 f - 1200 Celcius).
After reading all your advice I am considering on cutting the sprew not in the form. I cut mine always while the slip casted piece is in the form and I do it with a sharp wooden tool, but after reading your suggestions I think that I possibly bend all the pieces while cutting it one or different directions..
As well as, I might buy the EPK or grog to see how it might work.
Apart that, I also noticed that in some molds my cup rim thickness varies, some sides are always thinner and dry longer, does that mean that I should throw these molds and make new? I guess all products made on those forms are 100 percent makes bended pieces after glaze firing, just since bisque looks good - I've considered that it might come up well after glaze firing too, apparently I'm just having a false hope
Greta
