Originally Posted by
lotek
When I restored my Trek we used silica blasting material (i.e. sand) very fine grit. I asked David about it and the concern that it could etch away too much metal. His response was that I'd have to hold the sand blaster less than 2 inches from the frame, and then apply a constant stream of it for at least 10 to 20 minutes to do any real harm to the tubing.
My understanding is that the use of glass or nutshells as a media reduces the amount of excessive heat that sand creates ... which could possible warp the steel.
Scott