Originally Posted by Christopher Walrath
Ian, have you ever used automotive grade valve lapping compound and do you know of its effectiveness, pros, cons?
Automotive compond is coarser and faster. The coarser the grind the brighter the image but the more a center spot dominates.
"There are a great many things I am in doubt about at the moment, and I should consider myself favoured if you would kindly enlighten me. Signed, Doubtful, off to Canada." (BJP 1914).