Thanks Arnold - I'll give it a go.

One other thing - it's winter here in Australia and the daytime temp is
between 9-15 deg C.
Will the gelcoat properly cure at this low temperature?

"Ystay" wrote in message
...
Hi Hobbs,
a thick layer of gel coat is not really a good thing because it has no
fiberglass reinforcement. This can cause it to crack at a very slight
knock. The guru's will tell you that the ideal thickness for gel coat is
about 1 to1.5 mm. But in reality, you will find that many GRP parts have
gel coat in excess of that, sometimes up to 4 mm in certain areas. This
is one of the draw backs of brush applied gel coat. But anyway, your
repair should hold fine. Just make sure you catalize the gel coat to cure
real slow otherwise it'll shrink too much and wouldn't bond properly.

Arnold


"Hobbs" wrote in message
...
Another gelcoat / flowcoat question...

How thick can gel coat / flowcoat be applied before it becomes a problem?
I have a bubble at the deck/hull join area where evidently a bubble
existed under the gelcoat.
If I fill it with gelcoat it will be approx 2-3 mm thick. Will this
thickness cause a problem?

"Hobbs" wrote in message
...
Thanks Arnold - I'll give it a go.

One other thing - it's winter here in Australia and the daytime temp is
between 9-15 deg C.
Will the gelcoat properly cure at this low temperature?

Hi Hobbs,
no experience in that kind of temperature. But the cure depends a fair bit
on ambient temperature so you may want to catalyse the resin a little more.

Arnold

On Sat, 16 Jun 2007 16:39:25 -0700, LouiSurfer
wrote stuff
and I replied:

As has been said, the first batch was too old. Don't feel too sorry; I
have had 200 litres of resin go hard on me....once G!

The trouble with Gelcoat is that it's really designed for working
inside a mould, and not for brushing. It has additives that make it
flow more the longer you work it, but also make it stop flowing almost
as soon as you stop. The beauty of this for inside moulding is that it
will not run or sag, and of course the mould's surface gives a smooth
exterior appearance.

Wall plaster has the same tendency.

If you are really worried about finish then either very finely (600+
grit) sand and polish the area (practice on something that does not
matter first! You will also have to affect the surrounding gelcoat),
or I would ask around and find a basecoat and (pref 2 part) paint that
will do a better job if brushed, and are meant to go on
polyester/gelcoat. The 2-part urethanes are good.

About 3 months ago, I bought 1 quart of clear gelcoat. Didn't get
around to using it for about a month. When I went to open it up, it
was pretty hard and unuseable.

I bought another quart from the same seller about 2 weeks ago, and
opened it up within a week. This time, the consistency was about that
of grape jelly. At no time was any of this liquid.

I've worked with surfboard fiberglass resin and thought gelcoat would
be similar liquid consistency.

Am I wrong or:

a) Was unlucky, got two bad batches and need to take it up with the
seller?

b) Waited too long to use it? I don't see how it can harden up like
that within a week.

c) Need to add something else to liquify it or thin it, like acetone.
I tried acetone, but it doesn't take out clumping.

d) Leave gel-coat repair to a professional. I've done plenty of
fiberglass repair and didn't think gelcoat would be that different.

A little advice is much appreciated.

L.

Human bevaviour: Bestiality with a brain

Put the open container in a pan of water on the stove and warm it up.
Old dry hard crystallized polyester resin will liquify and can be used
when heated.
Not sure about gelcoat but worth a try.
Also worth a try is hacking some out of the container and warming in a
microwave oven on low heat. Gotta move with the times.