----- Original Message -----
From: "Fred Fillinger" <fillinger@ameritech.net>
Subject: Re: Europa-List: Layups Peel Off!
<fillinger@ameritech.net>
>
> All sounds reasonable, but I'm sure you meant MEK; methylene chloride
> (paint stripper) is one of few common chemicals which will destroy epoxy
> resin!
>
> #36-40 grit sandpaper can easier slice up the glass cloth, reducing
> strength. Also, I once tested grit vs. adhesion on 1/2" test strips,
> and #400 grit seemed to result in stronger bond than #50-grit abrasion,
> requiring more force to debond it. I couldn't measure that exactly, but
> viewed under magnification the #400 test strip resulted in greater
> damage to the glass fibers of the other surface.
>
> Regards,
> Fred F.
> N3EU
>
> > His method.....
> > 1) Check the temperature of the surface of the lay-up area. Get above
70'F.
> > 2) Wipe down the area of the lay-up with acetone or Methylene Chloride
to
> > remove any grease, oils, or mold release. Then don't touch that area
without
> > gloves!
> > 3) Use 36 or 40 grit sandpaper to really scratch up the surface for
bonding.
> > 4) "IMPORTANT PART!" Lightly brush the area with your resin mix.
> > 5) Then apply the lay-up. Either by laying down the glass on the area
and
> > wetting in place or wet out the lay-up on plastic sheet and apply all at
> > once.
> > 6) Keep the temp up for at least four hours.
Cheers,
I seem to remember Boeing coming out with the caveat that if,
when you have roughened the surface, you can get water to 'sheet' on it, it
is ready to accept epoxy efficiently. I have kept this in mind, roughend
with 200-400, first coated very lightly with epoxy pure and allowed it to
'spread' like the water (mere glisten), then attacked with whatever layers.
My test samples cannot be delaminated, so am content. But I'm no expert so
correct me.....
Ferg
A064
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