There was a rather heated argument on this subject a long time ago. The general concensus was that unless this can be done in a controlled environment, it is risky. The epoxy will begin to break down at temperatures approaching 200, and without controls this could easily happen. Somebody was proposing wrapping the boat in a black plastic shrould and leaving it out in the sun, and some builders (CLC?) chimed in with a safety warning.

: Hi gang - My post of September 4 regarding the changes in epoxy/varnish
: finishes on my boats only brought one response. I emailed MAS Epoxies with
: the same question. Here is their verbatim reply: In a message dated
: 9/11/2000 2:13:49 PM Eastern Daylight Time, MASEPOXIES writes: > J: Yes
: pro builders have the same problem. What you are experiencing is a very
: well known phenomina of immaging or printrhrough. This means two thing,
: one you sevel of finsih and gloss are excelent, and two your boats are
: aging in a normal fashion and experiencing a slight degree of additional
: curing. With this slight additional cure comes a minute amount of shrink
: and thus immaging of the glass especially noticable on a dark very glossy
: finish. To reduce the immaging the boat needs to be thermally aged prior
: to final sanding and finish. How to do this is the tough part. Some folks
: heat (120-130) then cool the part a few times (thermal cycling) just like
: in real life. In simple terms the next time you sand and refinish the
: problem will likely dessapear for ever unless the boat is taken to a yet
: warmer environment (southern floridda and stored in a black bag). The pros
: tell the owners that their is always going to be some immaging and when
: they repaint the boat the problem will releave itself. Sorry I can't be of
: greater help.

: Thanks for your question Tony

: In spite of the typos, I thought the response was very informative. None of
: the books I've read on strip building mentions the effect, although it is
: apparently common. Is this effect only with MAS, or does West , System 3,
: Raka, etc. have the same problem? I wonder how I could "thermally
: age" the epoxy without exposing it to sunlight with no UV protection.

: I will still build! - John