I use 4-ply Mylar because that's what I have on hand. You can use any paper -- freezer paper, parchment, wax paper. The clay works well in this recipe; not so much, I guess, in tallow/stearic acid recipe that's popular on SMF, although I've never tried that one.
That is a matter of personal opinion. I use Kaolin clay in my dual lye stearic acid shave soap and have no issues with it at all. But then again 3 teaspoons in a 3 lb batch is quite insignificant. My blades last for over 5 shaves which is quite good regardless or whether there is clay in the soap or not.
A volcano may occur if the oils and lye are too hot... usually it happens when adding the lye solution too quickly. One needs to constantly stir the oils whilst adding the lye solution to them. My second batch of dual lye and nearly had a volcano but stirred it down quickly enough to prevent an overflow.
Tallow gives a nice glide.
Thank you
