Alistair Blair Posted April 4, 2023 Report Share Posted April 4, 2023 Hi all, I was wondering if anyone has used Imery's replacement for SSP, Kaopearl, in a successful slip? I've tried a variety of recipes, the last being this one which I used to use for SSP. There would always be slight adjustments but now the slip seems to be unable to take more deflocculant and I'm concerned about raising the water too high to keep the specific gravity in the correct range of about 1.75 -1.78 28l water 250 antiprex 450 alcosperse 35kg China clay (SSP) 25kg feldspar 11kg silica Any thoughts would be appreciated. Quote Link to comment Share on other sites More sharing options...
Hulk Posted April 4, 2023 Report Share Posted April 4, 2023 (edited) Antiprex, a dispersant, rheology modifier, per worldofchemicals.com Antiprex 461 is an aqueous solution of low molecular weight polyacrylic acid. It is an effective dispersant and rheology modifier for kaolin, gold processing slurries and other mineral suspensions. It functions as an efficient antiscalant for the prevention of scale deposits including calcium carbonate, calcium sulphate, strontium sulphate and barium sulphate in industrial systems. Alcospere, a dispersant, per manufacturer's website Alcosperse® 149 is a pale amber liquid acrylate-based dispersant designed for general use in kaolin, calcium carbonate, paints, paper coatings and a variety of pigment slurry applications. Just curious. Hi Alistair, Welcome to the Forum. What are the units for those two ingredients? Edited April 4, 2023 by Hulk Kaolin for tableware. PeterH 1 Quote Link to comment Share on other sites More sharing options...
PeterH Posted April 4, 2023 Report Share Posted April 4, 2023 What defloculant(s) are you using? If there are other dispersants/rheological-modifiers about there may be interactions. I've no idea how the various sorts of deflocculants interact, so speculation follows. > Antiprex 461 is an aqueous solution of low molecular weight polyacrylic acid > Alcosperse® 149 is a pale amber liquid acrylate-based dispersant BTW https://digitalfire.com/material/sodium+polyacrylateSodium polyacrylate dispersants like Allied Colloids 311 and Darvan #7 are used as an alternative to sodium silicate in casting bodies used in ceramics. If you are currently using a polyacrylate defloculant it might be worth trying to something else/in-addition as there are already polyacrylates about.https://digitalfire.com/article/deflocculants%3A+a+detailed+overview PS Just for the record, a back-to-basics "lab-technician" guide to optimising the level of deflocculant in a sliphttps://static1.squarespace.com/static/527ac372e4b0d4e47bb0e554/t/527fd7f1e4b0c046bfa9b90d/1384110065234/Dispersant+Addition+Procedures.pdf ... and a longer presentation with some pictureshttps://www.yumpu.com/en/document/read/34584429/slip-casting-alfreds-clay-store ... I've no idea how this sort of clay interaction would react with the more ionic deflocculants IIRC neither discuss the use of multiple deflocculants (except soda ash + sodium silicate) Hulk 1 Quote Link to comment Share on other sites More sharing options...
Alistair Blair Posted April 4, 2023 Author Report Share Posted April 4, 2023 Thank you for the links Peter. I'll have a look and get back to you. We found previously that the antiprex helped with the slip solution if we had added too much alcosperse. Tom, the measurements are mL. Apologies for not stating what alcosperse and antiprex are and their units. Hulk 1 Quote Link to comment Share on other sites More sharing options...
Jeff Longtin Posted April 4, 2023 Report Share Posted April 4, 2023 Hey Alistair, While I know the 1.75 is considered the perfect SG have you had any luck with using more water than normal? In my own studio I work with a cone 6 porcelain and have no problem with the water level. (I don't measure in other words.) During the day, however, I work at a pottery that produces both cast and thrown stoneware pots. I did the SG weight test recently and found they like to run with a 1.68 SG level. (Meaning more water than normal.) Initially I thought that was a bit more water, than was necessary, but I realized the casters like it at that level so I let it be. Every clay is different and some adjust easily and some don't. A little experimentation can lead to unexpected results. Quote Link to comment Share on other sites More sharing options...
Alistair Blair Posted April 6, 2023 Author Report Share Posted April 6, 2023 Hey Peter, I just wanted to let you know I followed your advice and did the tests and seem to have come up with a workable porcelain slip. Much appreciated! P.S. Thanks for that jeff. I do sometimes go to 1.7 if I can't get it right but nice to know some people go even lower! PeterH 1 Quote Link to comment Share on other sites More sharing options...
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