Re: UV degradation on cured fiberglass

David A Froble

This will be a rather worthless response, because I really do not know how
quickly UV affects fiberglass, or I'd guess more precisely, the epoxy resin.

Dacron fabric, in Arazona, will be destroyed in 3-6 months of constant
sunlight. In Pennsylvania, it would be more like 6-9 months, possibly more.
So, the amount of UV will be a factor. As for damaging exposure, if I were to
take your multiple choice test, I'd GUESS 'B' and 'C' are both correct.

I'd be real surprised if some projects weren't worked on outside, in the
sunlight, or at least sit outside in the sunlight at times. Never seen any
caviets about this. You'd think there would be warnings if a few hours really
was significant.

Anybody chosing 'D' hasn't been to Sun-N-Fun and gotten a good sunburn in 2-3


Scott Christensen wrote:

Suppose you've replaced your cracked canopy's plexiglas, all the
fiberglass-work is complete, but you've run out of time and haven't
completed the fill, sand, prime, and paint steps.....

....AND you want to fly somewhere this weekend. :-)

Just how long can cured glass (no filler - nothing) be exposed to the Sun be
before the UV ruins it?

a) don't dare do it
b) couple days are ok
c) would take months in the sun to do damage
d) all this baloney about UV rays is a clever scheme by the
government to nail us all for more taxes to support the EPA
David Froble Tel: 724-529-0450
Dave Froble Enterprises, Inc. Fax: 724-529-0596
DFE Ultralights, Inc. E-Mail: davef@...
T-Soft, Inc. 170 Grimplin Road Vanderbilt, PA 15486

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