On Sun, 30 Jan 2005 21:14:08 GMT, "Cy Galley"
wrote:

You can e-mail Steve Beert at As I understand, the sand
blasting prepared the surface for bonding by roughing the epoxy without
cutting and weakening the glass.

Are you sure he wasn't bead blasting or even CO2 blasting. I've done
a lot of sand blasting and it normally accentuates any imperfections
rather than smoothing. I'd not want to use it on anything other than
steel and even then it will peen the surface causing a warping.

On fiberglass the resin is tough and the glass is hard. If there are
any variations between wet and dry they should show up.

Even the pre molded shells are often sanded through the gel coat and
into the resin. Then given a thin coat of microsphere mix which is
then block sanded with very fine grit.

There have been several G-IIIs at Oshkosh that had the entire wing and
tail assemblies done this way to get an unbelievably true surface. If
I recall correctly the one guy had close to 4,000 hours in prepping
and painting the surface. More than some put into building the same
airplane. that was an all white airplane with a little trim, not like
the lancair 320 that had the Winged goddess on the bottom. I think he
had over 4000 just in the paint and prep.

But for me, and fiberglass... I'd not let any one with a sandblaster
near it no matter how good they are supposed to be. To me, it's just
too risky.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

snip many layers