Peter- you mentioned doing naked raku and regular raku on the same pot. I like this idea, but what temp are you firing these pieces then? B/c were I take the classes they are firing the naked raku at 1500 and the raku pieces at 1800. How would this work?
At the raku firings I go to they fire everything at about 1030C. So I have to formulate things for this temperature.
Do you have 1800F glazes available to you (including a crackle)? Do you mix any of your own?
Do you mix your own bottom-slip for the 2-part raku?
1) This was a 2 part slip. It was put on fairly thick. However,, a few pieces did peel off so perhaps that could be it.
For a 2-part slip the main purpose of the 1st layer is to stop the 2nd (glaze) layer sticking to the pot, so it doesn’t need to be too thick.
A bit of food colouring in the 1st layer helps to make sure that you get full coverage coats of both layers over the entire pot.
I think I've had grey "whites" with very thin pots (the smoke going though the pot from the inside). However unless you cast your pieces
they are unlikely to be this thin, if they are, glaze them internally.
2) On this pot (the red t-sig) it is interesting what you suggested because I did put red t-sig on the body of the pot but left a small top portion w/out t-sig and it did accept the smoke so the rim of the pot is black, but on the body of the pot where it was t-sig the smoke completely came off.
That does sound like you overfired your t-sig.
PS You can mix naked and glazed raku on the same pot if you separate the different areas with a thin line of copydex
(a thick-ish latex glue), this leaves you with a blackish line between the regions. Remember to peel off the glue before
firing. Even just naked rake + plain crackle (same glaze) looks surprisingly good. Copydex is the only way I've found to
avoid trouble with the 2nd glaze layer of the naked rake touching the pot at the edge, and sticking permanently.