Fine cracks in gelcoat
John Lynch
The hull of my Mad River Explorer (fibreglass) shows many fine cracks.
It is probably 12 years old and has always been stored indoors on its
gunwhales. Are these a problem and if so, what do I do about 'em?
tia
john
Ken Cooperstein
Very fine cracks in gelcoat is usually a sign that the gelcoat is too
thick for the amount of flexing. Either the gelcoat was put on a tad
thick or the underlying composite material is not sufficiently stiff.
What you do about is ignore it. If it really bugs you, after 20 years
of exposure you paint it.
Ken
scott from new prague
not attempt to use an over the counter gel coat repair. Gel coat only
cures properly by using an airtight female mold or vacuum bagging.
The paint is going to give you a better finish than the gelcoat anyway.
Rutabaga
> John Lynch wrote:
> >
> > The hull of my Mad River Explorer (fibreglass) shows many fine cracks.
> > It is probably 12 years old and has always been stored indoors on its
> > gunwhales. Are these a problem and if so, what do I do about 'em?
They're not a problem unless they're through to the cloth, and then I
wouldn't worry about them anyway. Hairline cracks in gelcoat happen when
the boat is flexed, which happens when you use a boat for twelve years.
It's cosmetic, unless (as I said before) you have water seeping through
into the material, which you would notice. If you see bubbles developing
around the cracks, then it's time to regel the boat, but I've seen that
only once in maybe the 50 or 60 boats I've seen with *bad* hairline
cracks.
> The only fix is to sand, prime and paint with a good marine epoxy. Do
> not attempt to use an over the counter gel coat repair. Gel coat only
> cures properly by using an airtight female mold or vacuum bagging.
Uh, sorry but that's just not the case. Gelcoat cures just *fine* in the
open air. We do gelcoat repairs on dozens, maybe hundreds of boats a
year, as does the marine shop we contract with for bigger repairs.
Gelcoat cures by a chemical process, not an evaporative one.
> The paint is going to give you a better finish than the gelcoat anyway.
NO NO NO NO NO NO....
Do NOT paint a gelcoated boat. Unless you like painting it again and
again. Gelcoat is a much thicker material than paint, and will stand up
MUCH longer. Gelcoat will give you a fine finish, if you spend the time
buffing it out.
If the cracks REALLY bother you, try to match the gel with gelcoat from a
MR dealer (chances are it will have faded some). You can have a good
marine shop dilute the gel and respray the boat where the cracks are, and
then polish it. We did this for a gentleman last year and it ended up
being about $400 in parts and labor, which was fine for him, as he wanted
the boat returned to near-new condition (it was his dad's boat). Almost
all of the cost was labor (several days worth) of buffing. That being
said, the boat did look perfect.
Paddle your boat, and enjoy. Unless big pieces of gelcoat are flaking
off, don't worry about it.
Jay Norfleet
This is called "crazing". There is nothing that you can do at this point.
It will not affect the structural parts of the laminate.
Take care-
Jay Norfleet
Grateful Heads Kevlar Helmets
Rain and Snow, Inc.
555 Green Gables Rd.
Friendsville, MD 21531
301-746-4015
301-746-4012-fax
grat...@gcnet.net
www.GratefulHeads.com ....in a few weeks
John Lynch wrote:
> The hull of my Mad River Explorer (fibreglass) shows many fine cracks.
> It is probably 12 years old and has always been stored indoors on its
> gunwhales. Are these a problem and if so, what do I do about 'em?
>
> tia
>
> john
John Lynch
Hey all-
Thanks for the many helpful responses. It sounds like my best bet is
get the boat in the water where the cracks aren't visible and there are
no worries.
syotr-
john
Carl Busjahn
You have gotten some good advice here. You might want to consider
waxing the boat to keep water from getting to the laminate under gel
coat. Depending on the number of cracks you are looking at and the time
you might want to spend, there is a way to get rid of them without
spraying the whole boat. I've had good success with grinding them out
very carefully with my little rotary tool and a fine bit. Grind all the
way down to the laminating resin and even a little into it if the crack
goes into it a little way. You need to get rid of the crack completely
in order to keep it from comming back. (This is true if you have someone
grind and spray the whole boat also.) Then mix the gel coat, overfill
the groove slightly, let it set up, sand smooth using progressively
finer grit wet dry sand paper with lots of water, hit it with a
polishing compound and wax it. It sounds like your boat may be getting a
little soft in the chines. This will happen to a fiberglass canoe that
gets flexed enough times. You might want to lay a couple of stiffening
layers of cloth into the chines of the canoe to keep it from getting
softer.
Thanks for paddlin'
Carl
--
Carl's Paddlin' Canoe and Kayak Center
617 Williamson St.
Madison, WI 53703
608-284-0300 800-386-1299
ca...@paddlin.com