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Gell Coat cracks... Well the whole damn boat.

18321 Views 43 Replies 20 Participants Last post by kidcarbon, Nov 23, 2010

dieselboy

Discussion Starter · Oct 15, 2009

So my boat is getting to the point where i want to rework the upper decks.

I have two problems , one is the boat is 40 years old and the gell coat has seen better days the second is that someone applied cheep paint over it and its cracking and flaking too.
So do i strip it down to glass and re do it all?
smooth it as much as possible and fill it?
or just go over it?

P.S. these holes are no longer there. I have redone them and they are the best spots on my deck as of now.

Thank you all for your time and for putting up with all my dumb questions.

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tager

· #21 · Oct 18, 2009

One way to fix the deck is to stop looking at it. I got all gung-ho about fixing my gel-coat, and bought a can of gel coat, hardener, blue colorant, a respirator, gloves, wax paper, masking tape, plastic. I did three localized repairs on my boat, and realized that even a 24' was too big a project, and that I really did not care THAT MUCH. The boat sails fine, so I am happy.

GaryHLucas

· #22 · Oct 18, 2009

downeast450 said:
I have a severely crazed white gel coat deck. My Islander 28 was built in 1978. The gelcoat is crazed because, over time, the curing has produced such strong cohesive bonds in the gelcoat that the cured resin pulls itself tighter and tighter as it "shrinks" . Some bonds win and some loose. The result is crazing. 32 years of cross linking and I have a surface all across my decks that is cracked everywhere. There are stress cracks that are obviously involved in local movement but not necessarily failure. (That is another issue) The over curing also makes gelcoat more and more brittle over time so movement that used to be absorbed by the "new" more elastic gelcoat starts to cause cracks. The FG hull is not loosing its flexibility at nearly this rate if at all and is a strong matrix of cloth and resin so the crazing cracks at the surface are limited to the gelcoat coating.

I want to "fix it". My complaint about it is that it gets dirty and is hard to clean. I am not concerned about a flake of white gelcoat needing to be repaired occasionally. I want to fill the cracks. Not necessarily to make them disappear but to seal out moisture and make them shallower and "softer" so they do not look darker than the surrounding surface.

I have decided to use a 2 part urethane, flattened and thinned enough to gain good penetration. I will scrub the entire deck with a coarse Scotch Pad and or bronze brush. Working on small sections I can choose "cut in" lines that find the edges of texture or hatches. I don't want to fill the non-skid texture or sand it down. I could get fancy and paint things a couple of colors. Grey for the non-skid and white in between but that is a lot of additional work. If I decide that the cracks need to be panited again to reduce them further I can play with colors next year.

Now to find a color white that matches a 32 year old white gelcoat. On-Off makes it nice and white and etches it a little so that might be included in my pre painting prep.

No Sanding or Grinding down anything for this. Scrubbing and a bronze wire brush for the general surface. I do not need a gelcoat replacement just a crack filling and sealing.

George

George,
Good luck with this, having worked with the two part urethanes I just can't see this working. All the two part urethanes want to be applied over an epoxy primer. I'm betting that you're going to wind up with something that looks a whole lot worse than what you have now, after a year two. However I'd really like to hear how it works out, because the world certainly is waiting for a GOOD solution to this problem!

Gary H. Lucas

GaryHLucas

· #23 · Oct 18, 2009

cardiacpaul said:
Gary,
I understand exactly what you mean.
I've got the same attitude, and its only when I'm hanging upside down with a fuel barb, or exhaust elbow poking me for a couple of hours, barked up knuckles, fiberglass in places I forgot I had, the realization that I've got to hike my sorry butt up the mast again...

Then, and only then do the neurons fire... "what the hell was I thinking?"

I should take my own advise, eh? LOL.
And I miss it. terribly.

Paul,
I really don't mind working on the boat, in fact I enjoy the challenge of not just repairing something but often finding a better way to do it. What bothers me is I really do enjoy sailing too, and the work is cutting into the sailing!

I took vacation time this week. I was working on the cast iron keel this morning. I pulled it off the boat this time last year and got it sandblasted this week and I'm epoxy coating it and fairing it. My hope is that done right it will last long enough that 'I' won't ever being doing it again. After all it is 25 years old now and apparently never got pulled for servicing before!

I rebuilt the rudder too. I split it in half, got the shaft welded up, put it all back together, and foamed it. So that's ready to go back on in the spring.

I've already replaced the head and the holding tank, and through bolted the jib sheet track. I had the anchor sand blasted and regalvanized too.

Later this week the winter cover is going on, and I raised it so there is room to work underneath. I have new cockpit seats already made from Starboard, that I intend to install shortly, and the fixed ports will be coming off and replaced with new plexiglass.

I don't trust the Volvo saildrive much, though it runs perfectly. I have an inflatable dinghy with a 2005 Johnson outboard. I also have two Harken main sheet tracks and four cars, so I'm going to make a rail mount for the dinghy motor that will extend all the way down into the water on the stern. If the Volvo dies the dinghy motor can take over. It should make loading the motor onto the dinghy in the water easy too.

So progress is being made. The mast will get new wiring and a new VHF antennna when it goes back up too. I rigged up an A-frame and took it down by myself. It'll be going back up the same way.

Putting the boat back in the water is my main goal right now. The deck can wait!

Gary H. Lucas

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downeast450

· #24 · Oct 18, 2009

I have every reason to believe that my solution of a properly applied 2 part urethane will work fine.

I neglected to mention that I used to be an Awlgrip trainer and painter. For 15 years I trained painters at Maine's Marine Trades center. I had a 60 ton TrevelLift and could bring an 80 footer into my shop. We painted everything. With an On-Off etch an Awlgrip finish will adhere just fine to a polyester surface. I am not worried about the fairing I could do with an epoxy primer. I am not looking for a high gloss finish. Adhesion will be fine.

My Marshal catboat has been sporting an Awlgrip painted deck for 20 years with no problems. I added a little fine texture to that deck so it would look a little like a canvass surface and provide good footing. The interior is also Awlgripped and looks great after all those years of use. With no epoxy on the polyester surface.

If I were Awlgipping the hull I would certainly prime it with epoxy so I could fair the surface for the high gloss finish coat.

George

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sarafinadh

· #25 · Oct 18, 2009

3

tager said:
One way to fix the deck is to stop looking at it. I got all gung-ho about fixing my gel-coat, and bought a can of gel coat, hardener, blue colorant, a respirator, gloves, wax paper, masking tape, plastic. I did three localized repairs on my boat, and realized that even a 24' was too big a project, and that I really did not care THAT MUCH. The boat sails fine, so I am happy.

This makes me so happy...

So... gelcoat... and crazing, like wrinkles, seem to be de rigur for ladies of a certain age...

When we bought our little hole in the water we wanted a simple inexpensive boat that we could work and learn on while we figured out if we wanted to work towards another somewhat larger boat for cruising in a few years.

We did not have a survey. The survey would have been half the cost of the boat. We did read a lot about surveying old boats and repairing them. (thank you Don Casey.) Before we bought her I crawled all over her and poked into every nook and cranny and thumped and rapped and pushed and pulled anything I could reach. The only soft spot I found on her was around the bow dorade vent where the seal had visually failed on one side, and that area is pulp about 1 inch into the core and will have to be scraped out and epoxied and reset yada yada yada...

The rest of the deck seemed rock solid, and nothing we have done has revealed any areas of concern.

But the deck is COVERED with cracks and crazing, worse around corners and bends, but man, it is all OVER the place.

She has never been painted. There are a few places where stanchions were moved and the gelcoat was patched and is flaky. The rest of it, the original gelcoat is chalky but solid.

We have had much discussion about this. Currently we are heading in the direction of applying a gelcoat restoration polymer to seal her and put some shine on her. Himself is dying to pretty her up.

Our rational is if the crazing and cracking in the gel has not compromised the deck in all these years (she was laid in '67) then it is prolly cosmetic and all we would be doing is puttin perfume on a pig to attempt the overwhelming job of repairing or redoing the gelcoat.

What do you think?

This is what she looks like (without the black spots, we have scrubbed that all clean);

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Northeaster

· #26 · Oct 18, 2009

George - I am ceratinly not questioning your painting abilities, but, all that I have read has lead me to believe that the underlying cracks will show through, even the best laid paint job.
I hope you prove us wrong. Keep us posted!

My 30 year old decks are crazed somewhat, but so far, not to the point where I have decided to fix / paint them. I like that I can drop / pull the anchor chain across the deck, without having to worry about scratching it. I would doubt that paint would hold up as well to abuse, as the old gelcaot does.

For me, who also bought a fixer-upper, I have concentrated my efforts on structural and functional repairs and upgrades. The only cosmentic things I have done are a new teak and holly cabin sole, and sanding / varnishing the teak. As long as the crazing is not bad enough to let in water, I don't dwell on it, while I am sailing along, or eve enjoying a few brew at anchor.
I do have a few cracks in the cockpit, that may be letting in water, so I will be grinding them outt this winter, and making necessary repairs.

Sarafina, I am no expert, But some of those look pretty deep. May be worth a couple of drill holes to make sure sore is dry in worst areas. Easy to bevel / fill hoes with epoxy and mix a bit of gelcoat to cover them over.

If the core is wet, then you would have to determine how far to go on any further repairs.

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GaryHLucas

· #27 · Oct 18, 2009

George,
So you are saying you have already done this and gotten good results? I find that very encouraging, because I am not interested in a shiny new look either, just a well sealed deck. It is after all a 25 year old boat. My only concern is trying something that doesn't work, and having to do it all over again! THAT would be *****!

You mention and On-Off etch. Are you talking about the cleaner that is called On & Off? I believe it is muriatic acid based, and would probably etch the surface slightly. Do you neutralize it somehow, or just flush the heck out of it with fresh water?

Gary H. Lucas

Maine Sail

· #28 · Oct 18, 2009 (Edited)

downeast450 said:
I have a severely crazed white gel coat deck. My Islander 28 was built in 1978. The gelcoat is crazed because, over time, the curing has produced such strong cohesive bonds in the gelcoat that the cured resin pulls itself tighter and tighter as it "shrinks" . Some bonds win and some loose. The result is crazing. 32 years of cross linking and I have a surface all across my decks that is cracked everywhere.

George

George,

Your crazing is due to a gelcoat that was applied to thick or possibly over catalyzed for the temp in the original mix. Controlling the reaction rate and exotherm temperature, or cure profile, can affect the deck/hulls appearance moving forward by reducing crazing, cracking, blistering, and out-gassing. Many times you have to hot of a mix and a heavy spray and the gel will craze.

Gelcoat has no structure to it and if sprayed into the mold to thickly, to hotly mixed or both it can not with stand the normal expansion and contraction that the substrate experiences and eventually crazes. Cape Dory was famous for applying the gel coat to thick and others too. I have seen properly mixed and applied 40+ year old gelcoat craze free just like my 1979 is...

You can paint over the crazing but it will show back up again. Been there done that, even with the AwlGrip high build primer..

georgefmys

· #29 · Oct 19, 2009

Lots of repair methods discussed in this thread. Thougt IMHO most[that may not be successful] could actually take longer, and be more difficult, than what always works! I refer to removal of all gelcoat-on a small sailboat[say under 32 ft.]with the right sander and sandpaper can be accomplished over a couple of long weekends. The equipment is key-you need a powerful sander with a random-orbit action and just the right grit[this has to be trial and error based on hardness and thickness of gelcoat.]But 60 grit is usually about right. Don't waste your time on a low HP palm sander,save that for sanding the primer that you can roll on all surfaces to replace the gelcoat. There are always lots of areas that need hand-work,but if sanding blocks and next heavier grits of paper are used,then you'll still get job done.I don't remove every tiny bit of gelcoat,esp. in tight spots. If you greatly diminish the visibility of the cracks, even if not totally removed-then if cracks return the will be much fainter than otherwise.

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downeast450

· #30 · Oct 19, 2009

Your cracks will show through if you do what I am going to do. I am not interested in investing the resources in making them invisible, just not as ugly and to fill some of the space that has grown between them.

Getting them to "go away" would require grinding off the old, over cured, gelcoat off and replacing it with new gelcoat. That would be a huge job. My little boat doesn't need that to be sound. I want the cracks to become "softer" so they do not catch as much dirt and are more easily cleaned.

My boat's deck is not built with vulnerable core material so I have no worries about failed balsa core that has gone septic because water has entered the core. That is a separate problem if you have it. Then you do have a major repair on your hands.

My only concern is the cosmetics of the cracks. My gelcoat is intact but crazed. There are three places where small "chips" of gelcoat are missing. These are small, nickle sized, and I will patch them before I paint the entire surface.

What I will have when I am done is a white deck that still has crazing that is partially filled with a 2 part paint and doesn't look as "dirty".

I have no soft spots or chafed and worn spots where the glass is showing.

This old boat's hull was regelcoated at some point. That will require attention, too, but not this winter.

George

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downeast450

· #31 · Oct 19, 2009

Yes, The On-Off cleaner. I will wash it well before I paint it and a final alcohol wipe to dry the area where I am working. I expect no problems. Perhaps I will take some photos. My catboat deck , interior and boot stripe were Awlgripped this way 20 years ago and still look fine. I used a roller and a brush.

George

GaryHLucas

· #32 · Oct 21, 2009

downeast450 said:
Yes, The On-Off cleaner. I will wash it well before I paint it and a final alcohol wipe to dry the area where I am working. I expect no problems. Perhaps I will take some photos. My catboat deck , interior and boot stripe were Awlgripped this way 20 years ago and still look fine. I used a roller and a brush.

George

George,
I really WOULD like to see some photos!

Gary H. Lucas

dieselboy

Discussion Starter · #33 · Oct 21, 2009

WOW, hot topic...

So, i was once told by a very wise man that none of us are as smart as all of us..
I started this thread to see who has done what or tried different approaches to a major repair like this.

Not to speak for any one else's boat but mine..
My crazed deck does not appear to be a structure problem but shrinking gel coat. After a two week's of hard daily rain i hit her decks with a very high pressure washer. Then cut bunches of the cracks open only to find very shallow surface cracking the core is fine. I got" 0 "core damage or even dampness. After hours of cutting all the deep ones i could find i gave up and started sanding. 60 grit on a 6" da sander.

I did a 8' section with max bond epoxy/resin and the surface came out like glass. I did smaller experiments all over the boat trying to sand, pressure wash, dry with a heat gun, lay resin/epoxy let dry for a few days and try real hard to pry it off, cut it or blast it off with high water pressure.
the results are...... The max bond find's every nook and cranny and fills it and holds on like nothing i have ever seen.
i went so far as to try to force a razor blade in between the old and new with no luck. "The people at max bond dared me to .."it was able to dig in to the old gel coat but when i tried to pull it off the deck was lifting up!

Any way, I will be doing all the top side in this manner. then a good primer wit either a Algrip or Perfection top coats to finish it off.
I am more inclined to use the perfection rather than the Algrip. I have done a few tests and the perfection has won them all so far.

I planed to post up pic's during but i always forget besides a video would of been the only way to prove any of this.

I want to thank you all for your input even the people who were not very nice about it. We all have an opinion and they all matter.

To answer a few questions i have received:
1)No i did not get a boat inspection , mainly due to the lack of un biased opinion around here.
2) I knew how much work i was in for and LOVE to do this kind of stuff..
3) i am a Mechanical Engineer and a Heavy Diesel Tech and am no stranger to hard work, fabrication etc. I just wish they made a fiberglass rod to weld with. lol.
4) Yes i know my boat and i are the same age... 40

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sarafinadh

· #34 · Oct 21, 2009

dieselboy said:
I planed to post up pic's during but i always forget besides a video would of been the only way to prove any of this.

Ok, You are SO not off the hook here! I want pictures!!! Yes I do! Please, pretty please, with awl grip on top?

dieselboy

Discussion Starter · #35 · Oct 21, 2009

sarafinadh said:
Ok, You are SO not off the hook here! I want pictures!!! Yes I do! Please, pretty please, with awl grip on top?

:laugher Ok Sara, just for you i will try and shoot the " action" shots.
What do you want? before during after of a spot or the whole boat, small area?
I spoke with a chem guy out here and i was told this about the cracks we have:
They are a result of a to hot mix. The gel coat cured to fast and has been steadily contraction over the years. Forming the micro separation's we see.
The best fix was a good rough sanding for a texture and a filling with a softer resin/epoxy . Which is what the people at Max Bond told me as well. the surface needs to be rough, and very clean! the resin/epoxy must be THIN and flow well..

I have used their products before in the forming of Carbon fiber race parts and can attest to the strength under impact and resistance to heat.
They have a cool set up and do a bunch of stuff on ebay. If you are an insomniac watch the proper mixing of resin for two min and you will be out cold.. Great products and fantastic support.

http://cgi.ebay.com/EPOXY-RESIN-LOW-COST-FAST-SET-CAST-BOND-FIBERGLASS-24OZ_W0QQitemZ310170813411QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item48379f03e3

downeast450

· #36 · Oct 23, 2009 (Edited)

This is a very relevant and important topic for the DIYs wanting a cosmetic repair. I do understand the concern and risks of making it worse!

Having been involved in the "coatings" industry for 30 years I am blown away by the quality of the coatings we have access to now. The variety of chemical formulations is mind boggling too!

There are many different 2-part urethanes but the two-part polyester saturated, aliphatic urethane coatings are formulated and recommended for direct application to properly cleaned polyester gelcoat or polyester resin surfaces that are not gelcoated.

Epifanes violates an unwritten coatings industry rule and reveals the fact that no epoxy primer is required prior to the application of their two-part polyester saturated, aliphatic urethane coatings in their product literature. I share this if you are in need of industry confirmation, (http://www.epifanes.com/ecolors.htm).

The use of epoxy primer is very important if your goal is a high gloss finish. The primed epoxy finish is very hard and, if done properly, uniform in color. This provides a perfect substrate for building a very thin and high gloss topcoat. It is not required for adhesion. It will produce a surface that is less likely to have other problems of contamination that are often present in a "not new" surface. Careful attention to prep, if the goal is not a mirror, can eliminate these and provide an excellent bond to gelcoat. If you had to deal with customer complaints about your truly amazing topcoat formulation it would make sense to spec out a coatings system that didn't make your chemistry suspect if the surface being coated could be flawed. It also sells another batch of coatings. Paniting over gelcoat that is chemically clean will work.

I will collect some photographs of surfaces I have painted this way over the years and share them here. I may do a little photo essay of the crazing fix on my current boat, too.

One example I have out in the back yard now is a 15 foot pea pod I built 30 years ago. It is a Kevlar/vinylester boat that I drag along the river banks here in Maine when I am, "gone fishing". "If you can't drag it, don't own it." was my motto back then. It is a wonderful boat. The layup is flexible, tough and light enough for me to still lift it onto the car's roof rack. I used Dow's 8084.05 VDBN promoted vinylester resin, 44 / 22 S-glass and 12 oz. Kevlar to lay it up. After the un-gelcoated hull came out of the mold I painted it with a two-part polyester saturated, aliphatic urethane coating. It still looks fine. There is some abbrasion but the coating has no signs of adhesion failure anywhere. This little hull flexes as it slides over rocks and the coating is intact. It amazes me! The Awlgrip on my Marshall cat boat is almost 25 years old and shows no adhesion problems. Neither of these applications involved any primer. Photos to follow.

George

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Jeff_H

· #37 · Oct 23, 2009

George,

You are correct that within the industry, companies like Interlux (International) and Epifanes recommend that their urethane products can be applied over scuffed, clean healthy polyester or vinylester gelcoat without a primer.

I have specifically discussed this with various reps and they have been consistent in this recommendation. If I were painting the topsides or cabinsides of an almost new boat, I would not expect the gelcoat to have been primed.

But this thread is a discussion of painting a deck with bad crazing problems. In my research process, as soon as I mentioned decks and crazing to the paint reps, all bets are off. Then they begin to hedge and caviat themselves very carefully. Typically, they will say that the gelcoat needs to be 'stabilized' in some form or removed.

It was here that each of the reps had their own recommendations. Some literally suggested stripping all gelcoat, laying a veil coat of glass and epoxy (or vinylester) and then using thier products to finish the job.

Others suggested reducing the thickness of the gelcoat rolling the deck with a very thin layer of a saturating epoxy, then coat with an epoxy based promer because epoxy resin was involved and urethane does not stick as well to epoxy resin as it does to polyester or vinylester resins.

And still others recommend simply cleaning and scuffing the gelcoat, roll out what is effectively an epoxy barrier coat, and the paint with their topcoat.

The reason that I mentioned MAS epoxy rather than some of the other brands is that MAS makes a penetrating epoxy specifically for these kinds of operations, and MAS does not produce an amine blush. In most cases the lack of amine blush is only a minor advantage but in the case of a deck, especially one that still has some texture remaining, it is not very easy to properly clean the amine blush from the resin, and so long term there may be adhesion problems that result from the remnant amine blush as the decks age and are exposed to heat.

Jeff

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downeast450

· #38 · Oct 23, 2009

Hi Jeff,

Yup, You are absolutely right; dealing with an amine blush in the depths of a crazed deck would be a nightmare. Impossible. Using a primer, as you suggest, that does not bring this condition to the process is essential if you are going to use an epoxy in this repair procedure. I want to eliminate the epoxy step for my repair.

I want to be very careful in my post to make it clear that I am not concerned with possible subsequent minor gelcoat failures on this deck. I am starting with the understanding that I am painting over a 32 year old substrate that has begun to fail. Chips in the original gelcoat that may occur after I "clean things up", that are remnants of an old, weathered gelcoat will become spot repairs if they occur. I do not expect this to be a problem on my boat. They would be possible if I included an epoxy primer, too. The viscosity of a thinned polyurethane will be as penetrating as any epoxy formulation and the adhesion should be more than adequate.

George

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TomRay

· #39 · Feb 13, 2010

downeast450 said:
The Awlgrip on my Marshall cat boat is almost 25 years old and shows no adhesion problems. Neither of these applications involved any primer. Photos to follow.

George

I still want to see the old catboat!

kidcarbon

· #40 · Nov 23, 2010

Im trying to pm Downeast450

hello.

i am trying to PM Downeast450 but need 5 posts to accomplish this. so...

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