There is no need to complicate the vacuum bagging or any other epoxy process
with alcohol. Epoxies are available in a variety of viscosities and some are
water thin. Aircraft Spruce and Specialty, Aerospace Composite Products,
Composite Structures Technologies, Fibre Glast, Fiberlay, and marine supply
stores are sources for a variety of suitable epoxies as well as a variety of
thickening and hardening agents. Some of these more suitable epoxies are
starting to show up in hobby shops too. Once you try the good stuff you
won't go back to the thick, rubbery stuff or the stuff that leaves an amine
blush.
It is better to have on hand a high strength, low viscosity epoxy that sands
easily when cured. The viscosity can be increased with a variety of
thickening agents if the application requires them. This system is much more
versitile than the use of alcohol. Alcohol will absorb water vapor from the
atmosphere and eventually become unusable because of too high a water
content.
Vacuum just hastens the evaporation process and can result in boiling the
alcohol at room temperature if the pressure is low enough. A potential
problem is that the alcohol may be trapped between the bag and the work
before it gets a chance to escape. This can be aleviated by using layers of
peal ply and breather cloth.
Regards, Ollie
>What about thinning epoxy when vacuum bagging ?
>
>Will the alcohol evorate "successfully", due to the low pressures in this O2
>starved environment?
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