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Hello, I've been making casting slip using only sodium silicate. I would like to make some more today but am almost out of sodium silicate - I do have a lot of soda ash though. Is it possible to make a good casting slip using only soda ash? Thank you in advance.

Hi all, Second time posting here and I’m hoping you can help! Hopefully this is the right place to be for a troubleshooting question like this. Im currently working from a recipe for Val Cushing’s Cone 6 Porcelain Slip. grolleg: 15% tile 6: 15% Epk: 3% om4: 10% flint: 25% neph sy: 30% gerstley borate: 2% —————————— Sodium silicate: .0028% calgon: .0005% When I mixed this before, as now, I subbed the deflocculants with Darvan. I mixed it successfully then, but I’m currently have difficulty. I know that darvan generally subs for sodium silicate at 2-1, so bearing that in mind, that’s where I started. I kept adding darvan in small 5g increments up to 100g in a 10000g recipe. That seems like far too much, but maybe I’m wrong? I feel like I’m on the other side of that deflocculation bell curve some how and missed my mark. Every time I come back to the studio the slip is gelled thick but never settled and never develops a skin. When I’ve added more darvan, the slip temporarily thins, but seems to rebound to being too thick the next day. Can the casting process indicate overdeflocculation? If so, in what ways? What should I be looking out for other than settling and a skin in my bucket? Can anyone offer any advice on this recipe or deflocculants? I’ve been doing some hard research and testing and can’t nail it down. My current gravity is measuring at 1.71, so I’m hesitant to add more water, since according to some other online sources I should be aiming between 1.7 and 1.8. I’m wondering if I should throw caution to the wind and say “this slip just needs more water than most”. Ive mixed this slip before with great success two years ago. I have no clue what I did right then. Dumb luck haha. Any suggestions or advice would be greatly appreciated. Thanks!