> Polishing silicon with pitch is definitely an art. The alkaline slurries
> used with pad polishing tend to soften the pitch causing downgrading of
> the polished surface. There are techniques to get past this problem.
You don't have to use pitch for polishing. There is a compound called "tropical pitch" which is made of rosin, castor oil and woodflour (melted together). I don't think it will be susceptible to slurries as pitch is. Oherwise it's used in the same way as "normal" pitch lap - you can press it, cut it or form it with rubber mats. Drop us a line if you want more info.
Bratislav