Gellcoat (I think) flaking off
 

On Mon, 12 Apr 2010 04:38:09 -0700 (PDT), wheewhoo
wrote:

Thanks, Bruce, for the lenghthy and detailed reply, much
appriciated :)

I need to work out which product to go with I suppose. I was looking
at this on eBay:

http://cgi.ebay.co.uk/Epoxy-Resin-Ha...item334f06460f

How suitable would that be for my application? If not, that seller has
a "resin shop", can you see anything in his shop that would do the
job? Or if i go with a gelcaot, he has that too:

http://stores.shop.ebay.co.uk/resinshop__W0QQ_armrsZ1

Thanks again :)

I can't comment on costs but it seems sort of in the ballpark but I'll
warn you that epoxy varies considerable. I notice mostly viscosity as
some stuff is as thick as treacle and other lots are thinner and
depending on what you are doing you may want one type and other times
the other.

Try to discover Paul (Osman?) site. He posts here from time to time.
His site has an absolute wealth of information about every thing you
need to know. It is sometimes a bit hard to find things on the site
mainly because he has so much information.

His prices are in US$ of course, but you can get and idea of what to
use and how much it should cost.

I'll also comment that you can believe what he says.

Frankly I would not use gelcoat for repairs as epoxy is simply easier
to use. the working time, for example. is many times longer then
polyester. Also note the quantities of epoxy materials advertised and
the lack of polyester.....

Polyester sets up very, very, fast. I recently molded some air scoops
- about 1 foot by 1 foot by 4 inches. Using just polyester mixed with
color with 1% hardener I just had time to brush on a thick coat of
gelcoat, and place a layer of glass cloth into the mold. It is that
fast.

For repairs I really would recommend that you use epoxy and paint. I
do not want to be patronizing or insulting but from the questions you
are asking you really should start out with the simplest possible
repair and proceed to more sophisticated work on a later boat.

Gel coat is polyester and polyester over epoxy materials is not
usually recommended as it does not adhere as well as epoxy over poly.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Gellcoat (I think) flaking off
 

On Sun, 11 Apr 2010 21:19:59 -0500, lid wrote:

On Sun, 11 Apr 2010 11:13:54 -0700 (PDT), wheewhoo wrote:
Hi guys, thanks for the replies.

So what I need to do is sand off the gelcoat (and whatever other
layers are there), as I can definitely see the fiberglass where flakes
have come away.

Do I just need to prepare the bare (fiberglass) surface, and apply a
new gelcoat? Or do I need layers of other stuff also? Lets say I have
a large area of hull/keel that I have sanded back to the fiberglass.
What are the steps I should take? Phantman mentioned bottom paint, and
Bruce mentioned epoxy. Would it be epoxy, then gelcoat, then bottom
paint?

Thanks for the help!

On Mon, 12 Apr 2010 07:34:06 +0700, bruceinbangkok wrote:
The basic task if to protect the underlying fiberglass from UV damage
(a real threat in tropical climates) and water ingress which may take
place over a longer period of time. There are two basic methods, to
apply a gel coat or to paint, usually with an epoxy based paint.

The gelcoat is much harder to apply and have a nice smooth shiny
surface. The paint is much easier to apply but perhaps not as long
lasting.

Gelcoat Method.

Grind/sand, the damaged areas back to a good solid surface. This
surface can be either fiberglass or gelcoat but it MUST be a good
solid surface. If gelcoat you must be certain that it is attached
firmly to the underlying fiberglass.
Once you have reached your base surface you must then "fair" the
surface as smooth as possible as any craters, dips humps, etc. on the
surface will be mirrored in the final finish. You can do this by
grinding/sanding the surface until it is flat or you can build up the
low spots with an epoxy filler using any of the harder, stronger
fillers.
Once things are fair you then sand with varying grades of sandpaper to
about a 500 grip sandpaper.

Gelcoat is nothing more then polyester resin with a coloring agent in
it and comes in many colors. The mix also has a "wax" incorporated in
it that when it is applied floats to the surface and causes the
polyester to harden with a non-sticky surface.

The gelcoat can be applied with a brush or by spraying but no matter
how it is applied will probably not be the smooth, shiny, beautiful
coating that you have envisioned. It needs work.

Sand the gelcoat with progressive grades of sandpaper down to at least
1,000 grit and preferably finer. Once you have the surface as smooth
as possibly then buff the surface to the required finish using a
buffing wheel and polishing/buffing compounds as used for paint.

If you did a good job it will be beautiful.

Painting - Basically you do all the preparatory steps to get the hull
smooth and fair and then apply two coats of epoxy resin to seal the
hull. One method to avoid the "epoxy blush" problem is to apply the
second coat of resin before the first coat is completely hardened.
When it is no longer sticky but not hardened completely so that you
can press your finger print into the epoxy apply the next coat.
Finally after the last coat of epoxy (before it completely hardens)
apply at least one coat of epoxy high build primer.

Sand the hardened primer with about 400 grit sandpaper and do any
touching up, sand again if necessary, and spray two coats of two part
polyurethane paint.

It will be beautiful if you did a good job.

But don't kid yourself , either method is a substantial amount of
work. The gelcoat considerably more work, but neither is a Sunday
afternoon project.


Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Took the words right out of my mouth ^^^^ ;-)
... and I vote for the gelcoat method :-)
Rick


After writing that I happened to meet a mate who does this kind of
stuff as a business. He was showing me some very pretty "Biminis" for
a catamaran that he has just built with glass over foam. I asked him
of it was gelcoat or paint and he went into details about gelcoat.

He is now building these "bimini" or cockpit covers for Cats one right
after another. He says that they are actually lighter then canvas and
stainless, as less stainless is used. But he now uses gelcoat in
preference to paint as gelcoat is good over polyester and less good
over epoxy so he can build these things using polyester. The gelcoat
hardens "right now" as apposed to " sometime tomorrow " for paint thus
he has less idle time and he can build them faster.

He thins the polyester gelcoat with "Styrene???" and sprays it but did
comment that you didn't want to delay cleaning the gun :-) He
recommends sanding to whatever grade wet or dry paper you can get
1,000, 1500, 2,000, etc. and then buffs. As far as the finish he gets,
some of his stuff has been installed on million dollar boats and the
owners were happy with it:-)

He recommends paint over epoxy and gelcoat over polyester and is
pretty much using it on everything that he does now.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Gellcoat (I think) flaking off
 

After writing that I happened to meet a mate who does this kind of
stuff as a business. He was showing me some very pretty "Biminis" for
a catamaran that he has just built with glass over foam. I asked him
of it was gelcoat or paint and he went into details about gelcoat.

He is now building these "bimini" or cockpit covers for Cats one right
after another. He says that they are actually lighter then canvas and
stainless, as less stainless is used. But he now uses gelcoat in
preference to paint as gelcoat is good over polyester and less good
over epoxy so he can build these things using polyester. The gelcoat
hardens "right now" as apposed to " sometime tomorrow " for paint thus
he has less idle time and he can build them faster.

He thins the polyester gelcoat with "Styrene???" and sprays it but did
comment that you didn't want to delay cleaning the gun :-) He
recommends sanding to whatever grade wet or dry paper you can get
1,000, 1500, 2,000, etc. and then buffs. As far as the finish he gets,
some of his stuff has been installed on million dollar boats and the
owners were happy with it:-)

He recommends paint over epoxy and gelcoat over polyester and is
pretty much using it on everything that he does now.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Bruce,
What does this bimini look like? a canvas and frame bimini or a smooth
hardtop? Sounds very interesting.

Gellcoat (I think) flaking off
 

In article 4bce43e8-93dc-4b85-b754-d1c772a75ff2
@y14g2000yqm.googlegroups.com, says...

Thanks, Bruce, for the lenghthy and detailed reply, much
appriciated :)

I need to work out which product to go with I suppose. I was looking
at this on eBay:

http://cgi.ebay.co.uk/Epoxy-Resin-Ha...item334f06460f

How suitable would that be for my application? If not, that seller has
a "resin shop", can you see anything in his shop that would do the
job? Or if i go with a gelcaot, he has that too:

http://stores.shop.ebay.co.uk/resinshop__W0QQ_armrsZ1

Thanks again :)

Resin is more expensive than paint and as I noted before, guarantee you
will have rot soon. IIRC you built a small plywood boat from cheap
exterior ply? If this is the case, go to home depot and get some good
(not latex) exterior paint, even from the screwup bin a color you like
and paint the boat. It's crazy to go with gelcoat or similar on a small
boat and spend more painting it than you spent building it...

Scotty

--
Save the Ta'ta's!... http://tinyurl.com/ygqxs5v

Gellcoat (I think) flaking off
 

In article ,
says...

In article 4bce43e8-93dc-4b85-b754-d1c772a75ff2
@y14g2000yqm.googlegroups.com, says...

Thanks, Bruce, for the lenghthy and detailed reply, much
appriciated :)

I need to work out which product to go with I suppose. I was looking
at this on eBay:

http://cgi.ebay.co.uk/Epoxy-Resin-Ha...item334f06460f

How suitable would that be for my application? If not, that seller has
a "resin shop", can you see anything in his shop that would do the
job? Or if i go with a gelcaot, he has that too:

http://stores.shop.ebay.co.uk/resinshop__W0QQ_armrsZ1

Thanks again :)

Resin is more expensive than paint and as I noted before, guarantee you
will have rot soon. IIRC you built a small plywood boat from cheap
exterior ply? If this is the case, go to home depot and get some good
(not latex) exterior paint, even from the screwup bin a color you like
and paint the boat. It's crazy to go with gelcoat or similar on a small
boat and spend more painting it than you spent building it...

Scotty

Sorry folks, I think I posted to the wrong thread here..

Scotty

--
Save the Ta'ta's!... http://tinyurl.com/ygqxs5v