Join Date: Dec 2004
Location: Louisville, KY
In another post, this is what I said about alum:
"Actually I have used alum on a kard and it does being out the little subtlties. It is still in progress. What I do is have a dish with a little water and a lot more alum until it becomes a watery paste, heat the mixture, and apply with a brush or rag (use distilled water). It will take lots of time, but the results are interesting. Water and alum make a weak acid. Hope this helps. I would only use this with wootz from India or Persia."
Even when I heat both blade and solution, it still is a slower but very controllable process and brings out the wootz pattern. I use other etchant like Radio Shack (diluted) for PI and other stuff.