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Old January 28th 05, 01:31 AM
Roger
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On 27 Jan 2005 01:04:49 -0800, wrote:

How do you know when you're beginning to sand into the glass cloth? Do
you simply sand until you
have a smooth finish, then stop? Ot do you keep going?
thanks,


Are you sanding to get a smooth finish or to prepare for the next
lay-up?

If you are getting ready for the next lay-up you are sanding to "rough
up" the surface to get a good bond to the next layer, not smooth it.

With Vinyl Ester Resin I use 60 or 80 grit (hard to get a smooth
finish with thatG) and just rough up the area. I then vacuum the
area clean and follow up with an Acetone wash. With the area dry or
just barely tacky I do the next lay-up.

Generally you will see the difference when you sand into the cloth.
That will be a lighter color than the resin, or at least it is with
the epoxies and resins I've used. (West Systems and Dow Derakane)

Derakane (Vinyl Ester Resin) does not work with the Styrofoam (TM)
core lay-up method. It dissolves the Styrofoam in a hurry. OTOH it
is a much lower viscosity than most epoxies so a glass cloth with a
much more dense weave can be used.

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

joe mcguckin