International 14 Mailing List
| 14 | ||
From: Ross Abdurahman (ross@fsc.ca)
Date: Sat 29 May 1999 - 10:42:48 BST
Help....
Last spring I purchased a 1993 hull modified to the 1996 Rules. During
the modifications (and this is my understanding of what was done) the
gelcoat thickness was reduced by sanding and the hull refinished with a
two part linear urethane automotive paint.
After storing the boat this past winter the painted area of the hull
which rested on the trailer cradle blistered due to what appeared to be
water migration. While this was not critical there was a small crack in
the same area. While checking this crack out it became apparent the
that gelcoat appeared to have lifted from the hull.
A bit of further checking (with a knife) actually showed a complete
breakdown of the mechanical bond between the gelcoat and the hull
laminate. The gel coat removes in large (the largest up to 150x150mm)
flakes of paint and gelcoat leaving a nice clean carbon epoxy laminate
hull. We have cleaned this area of the most obivous loose gelcoat and
now have a clean area of about 600mmx1500mm. The gelcoat/paint on the
edges has become more resitant to removal, however, it can still be
broken away by a sharpknife edge in some locations.
Can anybody out there help me with some questions. First, can you
advise what is happening? Second what temporary fix is there and third
what is the permanant fix?
On the first. My guess a few things are happening. Water
migration....which I find amazing given that during cold storage in snow
the boat would in most cases been drier than during summer storage
between use.....is occuring thru the paint and gelcoat. The bond
between the gelcoat and the hull seems tenuous at the best of times. An
impact between a trap harness and the hull caused portions to delaminate
last season (repaired with fairing compound). Is this poor mech bond
common between expoy resin based laminates and polyester based gelcoats?
Is there a bonding agent between the two. There appears to have been
one placed on the hull. I tend to think that by reducing the gelcoat
thickness the mechanical strength of the gelcoat acting as a skin has
been reduced making it more proned to damage. Am I way off base?
On the second. I am located in Yellowknife, NWT, Canada. The ice is
just melting from Great Slave Lake. Our sailing season is very short
2-3 months, and with business travel and life in general time on the
water is a premium. Do you have any sugesstions for a quick fix. I an
drifting towards two options. Slap some gelcoat on the failed area and
hope for the best or fair the edges with some fairing compound and paint
the failed area with an epoxy marine paint to seal it for the season.
(This is only our second year on the boat so more damage due to poor
ability is very possible). Any suggestions greatly
appreciated.......especially cheap easy fast ones so that I can spend my
time sailing or otherwise having fun instead of with a sander.
Third, what is the permant fix. Take the hull down to bare glass and
then refinish? I assume that whatever it will be will be a winter
project of which we have a long one.
Any help anybody can provide would be greatly appreciated.
Thanks in advance for any help.....I really would like to spend my
summer sailing.
Ross Abdurahman, P.Eng.
Mechanical Engineering
FSC Group
<p><p>
This archive was generated by hypermail 2.1.4.