Brian,
I have bagged blue, pink, and beaded white foam with West 60 minute resin.
I have found that it is very important to thoroughly cure the resin. In my
experience, a 12-18 hr cure at 70 degrees F is not enough. The cure rate
approximately doubles for every increase of 10 degrees C. I always put an
old electric blanket on HIGH over my lay-ups and raise the temp to around 95
degrees F. I leave the vacuum on for a minimum of 24 hours. This is
equivalent to over 50 hours at 70 degrees I noticed that the paint releases
easier on FULLY cured parts. Epoxy also cures harder at elevated temps.
Others have written about an insulated heat box to raise temps further, but
bubbling of the resin can result at too high a temp.
From: Brian <[EMAIL PROTECTED]>
Hi,
My problem:
I've attempted my first bagging attempts and have produced 3 small slope
wings. 1 to 5 days after laying up wings using West Systems for one and
Araldite LC 3600 and LC 249 Hardener for the last two and Dow Roofmate
Blue foam, I get bubbles forming in places on the wing.
Used 15/18 inches for vacuum.
Beds were outside the bags, except one where the bottom bed was inside.
Under vacuum for 12/18 hrs.
Mylars removed 24/36 hrs after lay-up. One painted, two not all removed
ok.
Average temp during lay-up 20degc/70degF
Ample paper towels inside bag to bleed air and ski rope around perimeter
All excess resin scrapped off glass lay-up before bagging.
Wings looked fine when removed but bubbles formed next day or in the
case of the latest one "5" days later!
Bubbles were generally random and not very large but were predominately
in areas away from the L.E., T.E. and wing chord centre.
Sleepless in Stafford
Brisbane
Australia
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