wens

Agreed, but with it so thinned out I couldn't get a true specific gravity to plug into the formula - it was too close to 1. Next batch, I'll try not to thin it out too much. Appreciate all the info!

I think you may be right. Where I live, it's all red clay, rocks, and tree roots, but I did try to dig some that was less organic. I've followed Vince's method for all my other sigs, but there are so many methods out there that are more "shake it up and let it settle and pour off." Maybe I should give up some control. I don't know what color it will fire to, but here's a bone dry mini-bowl with Redart sig on the left (didn't stir it up very well), and ditch sig on the right. Hard to see the shine in the photo, but it does buff up nicely. I had some of it evaporating in a shallow pan with the dehumidifier on.

Thanks for all that, Peter! I've made terra sig numerous times from dry clay (Redart, etc.) and have a hydrometer. It's so watery that I couldn't get a good reading. Reading the last quoted thread, I got an identical bucket and filled it with water to the level my terra sig is, and weighed both. The difference is 102 grams, which should be the weight of the solids, since I may have not measured the volume accurately. But it's a good enough start for the deflocculant. I may have to start over with a larger amount of clay, to get a accurate reading, but I'll see how it goes.

Hi all, I'm making some terra sig from my backyard drainage creek red clay in NC. I need to deflocculate it, but didn't start with dry clay, so am not sure how to calculate the amount. I've got about a gallon of watery stuff that's almost there; a nice orange color. It's been strained to 100 mesh, then left to settle and removed the bottom sludge. It shines up when applied with enough coats, but it's too watery, and it could be better. I haven't measured the s.g. Do I actually need to dry this stuff out completely to weigh it, or can I approximate the deflocculant somehow? I could assume a half pound of clay and use something like 2g of combined sodium silicate/soda ash, but that might be too much? Should I try less and see if it separates? If I start over and dry out the initial clay stuff , rocks and all, would that be easier? I don't want to lose the finest particles coating the small rocks, but not sure how to figure out how much is clay and not-clay. Robin