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Showing results for tags 'deflocculant'.
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Hello, I am fairly new to slip casting (about 9 months), and have been trying to learn as much possible through books and videos. I haven't delved into making my own slip yet, instead I have been using Dover Slip from Miller (Laguna). It is a Cone 6 White Stoneware. I am having some issues with the slip: 1) A film forms on top the slip after sitting in the mold for about 10 minutes. 2) When I do the hand dip test no webbing is forming at all. 3) I believe the Specific Gravity is 1.8 (which should be right) I measured out 100ml and it weighs 180 grams. 4) It is pretty thick, pours out of the mold poorly leaving behind some gunk on the rim of the mold (makes for an uneven lip of my tableware) 5) It doesn't pull from the mold well, sometimes even 2 hours later I still can't get a simple cup out. Just for some addition information the room I am casting in lately has been around 85-95 degrees F, with pretty high humidity. What I am trying to figure out is if I need to add more deflocculant or if the slip has come over deflocculated from the factory, or perhaps I need to add more water. Thanks for the input. -Matt
Thought I'd share a success story here with my Terra Sigillata recipe. Everything I've ever read says that you need sodium silicate or sodium carbonate but it seems that Tetrasodium EDTA - aka Jet-Dry works as well. 3 parts Clay 1 part water 2 teastpoons Jet-Dry I used a small bottle to mix up a test batch as I wasnt sure that it would work at all. Previous attempts at using Calgon were unsuccessful as I read that the old recipe containing phosphates was changed. So, if you dont have sodium silicate or sodium phosphate handy you can give this a try and see if it works for you. Full post here - https://dreamsofearth.wordpress.com/2015/05/24/terra-sigillata/