gelcoat cracking

barolo

New Member
I just acquired, what I hope to be, a fun little sailboat that my grandchildren can learn to sail on. It is an '86 model and seems to be in decent shape. I know very little about boats but have picked some really valuable information today from this site in regards to "tweaks" and maintenance. The top deck has hair like crackl in the gelcoat in areas where I presume are stress points of the boat. They dont appear to be to be delaminating, but I am concerned, if in time, they are not sealed, they could be. Is there something special to put on these or is a good gelcoat cleaner and polish adequite ?? Thanks
 
I have the same problem with my older boat as well. I sealed the cracks with silicone and now wish I hadn't. Over time the silicone has discolored and looks bad. On the other hand, it keeps water out of the cuddy.
I'll be interested to see if others have a better solution.
 
cracked gelcoat

Thanks for the reply Clarke. Well I guess I can scratch that remedy off my list. That was one of my thoughts as well. I think Ill mosey over the hill to Oakland/Alameda and check with West Marine in the next couple days. I will post the answer to this perplexing question if the trip is successful :)
 
I think a lot depends on whether you can easily flex the cracks open or not. If not, there really isn't anything you can do that will make them disappear short of getting out the grinder and attempting some sort of patch. Chances are you will make more of a mess than you will fix. The fact they are stiffly shut indicates the resin/glass underneath is still sound and waterproof. For example, I have a dozen hairline cracks around the deck/rub rail area where my boat spent some of its life tied to a dock and suffered periodic bashing. I would leave such cracks alone.

If the cracks are fresh from impacts, and can be flexed open, you can try easily fixing them by working in some epoxy. Mask them off first to protect the surrounding gelcoat. If they are old cracks, they need to be cleaned first. I would use alcohol. Such a fix isn't very strong and it assumes you will not suffer further impacts in the same place.

If the cracks are from stress and are getting worse, we're talking major fiberglass repair. Evidently the underlayment isn't strong enough for the intended purpose and needs to be reinforced. :(

Hope this helps,
Jim
 
cracked gelcoat

Thanks Jim, thats some sage advice. They are "stiff cracks" like you mentioned. I'm thinking that a couple coats of wax will be the best protection that I can render at this time.
 
barolo said:
I'm thinking that a couple coats of wax will be the best protection that I can render at this time.

I agree. There are also some nice deck cleaners that work pretty well on fiberglass boats; they leave a protective coating similar to wax in that they inhibit the adhesion of dirt. I like Starbrite Non-skid Deck Cleaner with PTEF.

BTW, at the risk of destroying some widely held myth, one coat of wax is just as good as a hundred. Each successive coat applied dissolves the previous coating. After it's dried and buffed, the protective layer remaining is invariably only a couple microns thick.

For those of you who have labored needlessly applying multiple coats of wax, and now have more time for sailing, you're welcome! ;)

Jim
 
Gelcoat repair

I have had great success with Home Depot ename//polyureathane floor and deck paint colormatched by HD to match gelcoat on boat. It take about 6 hours to dry and in the ensuing time it flows easily into all cracks. In about 48 hours you can sand it down and no more cracks. So far lasted 5 yrs.
 
Thanks for the info Solarfry. Wow if that works what an easy fix. I imagine that with paint on gelcoat, the exterior maintenance upkeep might be a little more work ?? How did you prep the nonskid surface for painting??
 
Solarfry said:
I have had great success with Home Depot ename//polyureathane floor and deck paint colormatched by HD to match gelcoat on boat. It take about 6 hours to dry and in the ensuing time it flows easily into all cracks. In about 48 hours you can sand it down and no more cracks. So far lasted 5 yrs.

This sounds like a great idea but I'm confused. Are you saying you sand off all the paint except what goes in the cracks? And were your cracks the kind you could flex open or not? How did you get them to color match your gelcoat? Did you take in your rudder?

Jim
 
Paint that gelcoat.

I used a whole bottle of alcohol to dewax crack. First clean around it about 4" to each side with alcohol using a clean cloth (old T shirts work great). Then use a paper towel to clean again. Then pour alcohol over crack.

Use an artists small paintbrush that covers crack and about 1/4 to 1/2" to each side. paint one coat only. (Do not fix it if you screw up. Remove completely) One easy soft stroke with brush at a 45 degree angle or 30 degree so you are just kind of kissing it. Then walk away for a day or two. Do not touch for minimum 24 to 48 hours. Paint will sink into hole. In 2 days apply another single coat. Wait another 48 hours or more for paint to harden solid. If boat in garage give it a week. Then sand with 700 grit lightly, follow with 1000 grit then 2000 grit. I covered areas around paint with blue masking tape to keep from sanding them down. removed it at 2000 grit level.

You migh want to tape area under crack so if paint drips it will not ruin other work. Remove tape carefully after about an hour or two.

Best part is that with a piece of gelcoat HD can mirror the gelcoat color where you can't tell diff.

After a couple of weeks just use regular wax on it.

best
sf
 
Paint on gelcoat

I just painted it. It matched so well that you could not tell where paint began or where crack had been. One piece I had to sand because hairline crack sucked all th paint in.
 
Solarfry said:
I just painted it. It matched so well that you could not tell where paint began or where crack had been. One piece I had to sand because hairline crack sucked all th paint in.

Thanks Solarfry,
I don't think this will work for most of my cracks. They're so tight that even dirt can't get in them, much less something as thick as paint. But I have one crack I've been watching right in front of the mast step. If it doesn't get any bigger, and it doesn't need major repair to reinforce the step, then I'm certainly going to try this. There are gelcoat repair kits on the market which come with various colors you're supposed to mix yourself to match your boat. Yeah, right! Like that's really going to happen. Getting the paint matched at a paint dealer takes all the guesswork out of it.

Thanks again!
Jim
 
Gelcoat.

This is a paint. It takes 6 hours to dry to touch. almost 36 hours to dry hard. It will flow into tiniest crevices, including hairline cracks. I used it on hairline cracks. wider cracks need to be filled in with epoxy or fglass.

You can buy a gallon of this stuff for $21.00 or a quart for $10.00. It's made by Glidden and used for porches and decks. It's an enamel polyurethane Do not use for underwater surfaces. It will not survive long term submersion. But it will survive in FL under continuous rain and high humidity.

Keep can covered to prevent it from drying up. Once it dries up a little it will not flow as well as when it was fresh. It needs to flow to work right.

It's your decision on whether to try it. All you got to lose is $10.00 bucks plus tax and a trip to HD. We all go to either hd or low once a week. There is no project that can be accomplished without repeated trips to HD or Low. Heck a tiny tube of gelcoat is now going for $15.00 bucks around here.
 

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