I answered some of the comments in comment form so I hope you have found the right clay now. I'll blog some more on the clay but will talk very briefly about metal edges. The pieces are applied to blockboard which has been covered with handmade paper and painted. I sometimes work on heavy Vilene with gesso worked into it. Here is an earlier example from my Buddha series, with some cast water soluble paper forming a border. It is in a half painted state here.
Then I stitched a strip of fine metal shim around the edge. The shim was drawn into to make the embossed surface. The entire background was then glued to the board and the metal was wrapped around the edge and held with copper tacks.
I cut into it to make the scalloped edge.
Hope this helps. As you know, I don't like my work behind glass as textiles are so tactile.
So good to have West Country Mother back with us (aka Wittering Rainbow or Annabelle). I felt quite bereft when I got back from Jersey to find you had disappeared. Sorry about the problems with 'lady'. Elli Woodsford had similar troubles when her email was 'painted lady'! I have to say that West Country Mother sounds a bit worthy and not at all how I see you. Brings to mind rosy cheeked ladies at Farmers Markets but perhaps that's better than the Painted Ladies.
Well Hung has not caused me problems Aussie Jo, except that I think people think it is the name of the exhibition. I shall be in a lot of trouble with Highcliffe Castle as it is actually called Fusion.