Fiberglass Gelcoat Repair???

Quick question on repair. I had someone here do a repair for me on my fiberglass boat. I told him I was not really concerned about looks, but about function. I had him repair some worn areas on my keel and add some gelcoat around a spot where the gelcoat was cracking / chipping.

Well, he followed my guidance about not worrying too much about how it looked. He taped off the areas to be repaired and then brushed gelcoat on with a paint brush. It is very noticeable b/c of the difference in color between my grayish colored hull and the bright white gelcoat he painted on. I now have a big bright white diamon shaped spot on the side of my boat where there used to be the small gelcoat chip / crack. My goal was to reinforce the spot and to add to the resale value of the boat should I ever sell it (since an obvious crack / chip would not be appealing to a buyer). I think it really made the resale value go down though due to the fact that it looks pretty ridiculous and really screams out to someone that I have repaired this boat, and looks like a real ammature job. In short, it really looks like a crap job.

So…I don’t mind too much that it does not match, but I really expected the gelcoat would be smooth and flush (not painted on like white-out).

Can I sand this be sanded down / blended in? I have never worked with gelcoat before. Is it normally brushed on and then blended through sanding? I have no idea.

Incidentally he charged me 3.5 hours worth of labor for doing this to about a 12 inch section of the bow, and a 12 inch section of the keel, painting the big 6 inch diamond on the side of the boat, and then adding some sort of resin on the inside of the bow hatch where the keel was wearing through. Again, I have never worked repairing boats, but this sounds more like about an hour’s worth of work to me. What do you think?



not having seen it
and not knowing his level of expertise it is hard to evaluate. It generally takes me at least two hours to do some gel coat repair. Prep the shop, prep the area to be repaired, drink some coffee, mix some gelcoat, apply some gelcoat. drink some more coffee, sand gelcoat, drink some more coffee then sand some more. I have been able on occasion to get the hull perfectly smooth. I have never been able to match th egelcoat in color. Even using the same gelcoat it will not match. The gelcoat is effected by uv so it will have faded/ cured. new stuff never has matched exactly for me.

Don’t have to see it … sorry Bowler1
You just paid someone to muck up your boat … another horror story. Ugh …

I would bet that he did not prep the entire area for that brushed on huge area so you could probably take a utility blade and flake it right off.

Beware though, this person sounds like a real hack and the area might be so large because he just kept screwing up over and over.

Scroll down to “How to touch up a minor surface scratch” … this is how Professionals do it when time, money and finicky customers are at stake.

I know nothing about gel coat repair, but to be frank, sounds like you got hosed.

For what it is worth:
Two years ago I dropped my QCC kevlar kayak off the roof of my vehicle and it took a piece of the gelcoat about a half inch wide and three inches long off the bow below the water line.

I called up Phil at QCC and he said to fill it in with two part epoxy, sand it smooth and then spray it with automotive paint (like the cans you can get at Advance Auto) that matches the hull color, (in my case white).

I did and it has been fine ever since, although it now needs to be painted again since it is right where the bow hits the beach when I come ashore and the paint has worn off.

So: perhaps you can sand it nice and smooth and then see if you can find a paint to match and go from there.

I also suggest that if you do go to sell the boat you point out the patch to prospective buyers.

When I sell a boat, the first thing I do is point out every flaw that I know of, and then I don’t have to worry about the buyer coming back complaining that he got screwed.



Hey Matt
Sounds like your communications could have been a little more explicid.

There is nothing wrong with brushing on gelcoat to make a repair. Yes, you can sand the gelcoat that is there in order to fair it and make it look better. However, if you are going to that much trouble Id go ahead and do it correctly.

Do as Patrick suggested and read the information he sent in his link. Try and determine the status of the gelcoat that your guy applied. You should not be able to flake it off and you should be able to flex the area a bit and the repair should stay intact. If the repair starts flaking remove it all and start over. If you determine that the gelcoat is good then sand it down just beyond a good finish. Mix a small amount of gelcoat and add color to it to approximate the original color. I would use a small roller to apply the new gelcoat. I place a piece of plastic rap over the new gelcoat to improve set up. Sand the cured gelcoat with finer and finer paper until you are at #400 wet paper and you will have a nice repair.


Old Town sells a gel repair kit

Good luck, and keep paddling.

The Repair Person
obviously not a professional. Probably didn’t charge you as a professional would either.

A professional would have done a decent to good job, regardless of your instruction about not really caring how it looks. A person who dabbles with DIY would do what you ended up with.

I do believe he spent three hours, if he did any prep at all. If he just slapped on the mixed gelcoat, well… Maybe it was an hour.


DIY references…check it out!
I don’t have very much woodworking/mechanical experience, though I have built a stripper, am completing my sof and repaired the gel coat on an old Sirius and will do the same on an old Diamante I have. I used the following sites as references. Brian Nystrom’s site has some great pictorials. The Atlantic Kayak Tours site is extraordinary overall regarding information, including gel coat and keel strip repair. Questions regarding gel coat repair have also been posted on

As a novice builder…I found the gel coat repair to be relatively easy.



If it were mine
I’d try to see if the “repair” will come off easily and just do it myself.

I used a repair kit from Mad River on a boat I used to have. Followed the instructions included with the kit and got surprisingly good (almost invisible) results. Granted, my hull was white, so that probably makes the color matching a lot easier. With a bit of patience, super fine sandpaper, and multiple thin coats, I think you’d be surprised at how easy it is to patch relatively small areas.

On a previous boat I had a professional local builder do a repair (cracked hull, expensive carbon boat). He did an awesome job on a 6" or so crack. It was an open canoe, but the crack was still hard to work as it was right in the leading edge of the bow. The repair was visible (no gel coat to cover the problem), but it was extremely neat and seemed quite strong. He charged me $40 if memory serves correctly.

In the process

– Last Updated: May-22-06 11:03 AM EST –

I am having extensive damage repaired. The glass had to be sanded down and reglassed in spots. The process is so far nothing like yours. The gel coat is going on today and will be sprayed. The repaired areas have already been wet sanded at 600 grit. After spraying and drying the areas will be resanded with up to 1000 grit and buffed and polished. This is a brand new boat that was damaged in shipping. It aint cheap.
Note: for small chips, West Marine sells a repair kit for use on fiberglass boats. I think it costs about $12.

I probably could have been more explicit. When I said I was not concerned about the looks too much I really meant that it did not have to match perfectly / be polished to perfection, etc. I did not really expect brush marks, ridges, air bubbles etc. I also expected that it would be flush with the rest of the boat and not raised.

I was not trying to imply in my original post that I would try to conceal a repair from a potential buyer, just that I wanted it to have a subtle appearance and not be so blatently obvious as this would turn off some people and maybe cause them to question the soundness of the repair.

Incidentally, the guy is a professional. He charged me $35 per hour which is probably a fair rate for around here…but it just does not appear like 3.5 hours worth of work. I guess this is like crying over spilt milk. Now I just want to figure out where to go from here.

I imagine that he probably did prep it correctly. I am still debating over fixing it myself, taking it to someone else, taking it back to him, or just living with it…looks like crap, but I guess it is functional.

We’ll see.


Matt, he is NOT a true professional in
my interpretation of the word … tell him I said so : )

It is very easy to even make a token effort to get white real close to any grey and a pro would know that and at least take a medicum(sp?) of pride to do so if he was charging by the hour. Ugh…

A touch black and maybe some gold ( the colormatcher’s magic color) + a tiny bit of color if need be is all it takes … AND a good eye of course.

If you do it yourself just try a bit of black first.

question on color match
I know it’s hard to get a color match on gel coat, so I’m wondering, if for scratch/gouge repair that is not thru the color, wouldn’t it be easier to just use a clear gel coat? It would seem that in most cases unless it’s down to the cloth that this type of repair would give a very good color match. When a boat is wet, the scratches don’t show much at all, and it would seem that a clear gel coat have the same appearance as a wet hull.

Obviously if glass repair was involved this would not work out.

There is clear ‘gel coat’ sold at marine
stores for this purpose. Generally in a small tube and seems to be precatalyzed because it requires no hardener to use. Have used some a few times on very small and insignificant gel coat cracks, scratches, chips, etc.

If you can live with the color
difference and your confident this was prepped carefully, you should be able to slowly sand this down and buff to the or close to the original hull shape. It sounds like this person just didn’t do this final step–strange as that is.

If you can’t live with the color difference (which is strange that a professional didn’t do a better match job–maybe he just assumed your hull was white and only brought/had materials for that hull color), your going to have to do a fair amount of sanding to remove the white color of the patch down below the line/curve/shape of the hull and then apply color matched, catalyzed finish (finish = waxed; or non-waxed with added surfacing agent) gelcoat. Then sand to shape with progressively finer sandpaper and then buff.

Sounds like alot of money for what you got though. Bummer.

“Sounds like alot of money for what you got though. Bummer.”

Agreed. I had assumed that the gelcoat would at least be flush with the surface of the boat and that it would not show air bubbles and brush marks. I don’t know much about glass repair, but I would have never guess that it would look like this. I also did not realize how far from white that my hull actually is (older boat and no longer pearly white).

I think that the guy charged me for what the job should have taken if done right, and then did a crap job in about half the time.

The bad thing is that he “is” kind of a friend of mine…

I was somewhat amazed when he gave the boat back to me. It would be like taking your car to a body shop and them painting it with a roller or a brush.

Like I mentioned earlier…I did tell him that I was not too concerned about how it looked, but never would have thought he would take my comment to heart this much!

I can live with it for now, but would like to improve upon it. Since the coat his brushed on is so thick and has so many ripples / air bubbles / brush marks, etc. I think it would require A LOT of sanding. We’ll see.

I wish I knew how to post pictures here, as I would love to show you the job he did…it is so bad that it is really pretty humerous. I would have never imagined. It may be functional as I had told him was my preference, but you could not get it to look much worse if you tried.



Look at the bright side…
…you’ll get some experience sanding and blending his crappy repairs, then you’ll be able to do it yourself next time. There WILL be a next time…

Here’s another link to my online instructions on Webshots:

BTW, the Gelcoat Repair album is by far the most popular. It’s had over 80,000 views!