Gel Coat Repairs

-- Last Updated: May-04-16 6:58 PM EST --

I have some gel coat repairs to do on my Wildfire. The major issue is at the bottom of the stern end where there is about 5 inches of missing gel coat.

I hate to do it from an esthetics perspective, but I’m thinking of putting a strip of fiberglass here. It’s a spot that is going to get further abuse, and there is already a small leak into the float tank. At least it is at the bottom where it will be less noticeable, and I can paint it red to blend it in?

What do you think?

I have gelcoat repair instructions…

I suggest repairing the gelcoat, then installing a fiberglass rub strip over it. There are also some self-adhesive rub strip products on the market, but they’re pretty pricey.

Easy fix the way I do it Eric
and this came from the QCC people.

Over the years, I have done three or four repairs exactly like what you have on different boats

Sand around the area, being careful not to sand into the fibers.

Clean the area with acetone.

Mix up some West Systems two part epoxy and put in some of their thickener so it will be like a honey consistency and not run.

Put it on with a small brush. Don’t put it on too thick. Just enough to fill the void.

As soon as you put it on, use a piece of thin flexible clear plastic, like overhead projector stuff or note book page protectors. Cut it a few inches all the way around bigger then your repair hole and using masking tape, tape it down as tight as you can over the repair.

let it stay over night, and then take the tape and plastic off. This will give you a smooth glass like surface.

If for some reason the repair has sagged a bit just repeat the process. Once you are satisfied use a fine grit sand paper just to scuff the hardened surface to accept paint.

Mask around the area and use a good grade automotive spray paint like you get at Advance Auto, (match as close as you can to the original) and follow the directions on the can.

Over the years, if you do a lot of beach landings, the paint will probably wear off, but the epoxy will stay, and you can just recoat the patch.

If you do your repair on a cool day, you might want to wait two days to remove the covering. Epoxy hardens quick in warm weather and slower in cool

Good luck,

jack L

There are a ton of videos on the web on how to make gel coat repairs. The thing is that it all looks very tedious, but actually doing it is very easy and the end product will look just like new if you follow the procedure.

Maybe the most important ingredient is to get the right products. You will need to know what type of gel coat the manufacturer used and if possible the color code.

Secondly, the environment (temperature) is fairly critical. Third, I would highly recommend that you purchase a very good variable speed electric polisher. If you happen to live near a Harbor Freight store, they have two very good machines that are reasonably priced in the $50–$70 range. Watch for a sale.

by Greg Swenson Printable

Fiberglass isn’t the easiest material to damage, but it does happen. Don’t be disheartened — the situation probably isn’t as bad as you think. There is no fiberglass damage that can’t be repaired.

The first thing to do is survey the extent of the damage. Is it superficial or structural, minor or major? Perform a visual inspection inside and outside of your kayak. If you see white stress lines in the fiberglass (inside), it is structurally damaged.

It is possible to get cracks in the gel coat finish without any real structural damage. Most gel coats are polyester based and brittle, but many kayaks (like NC Kayaks) are now manufactured with vinylester resins, which have much more flex than polyester gel coats. So the fiberglass can actually flex more than the gel coat without sustaining any damage.

Once you establish what needs to be repaired, we can determine what needs to done.

For gel coat cracks

1.Sand the cracks all the way to the fiberglass.

2.Mask off around the area to be repaired with masking tape.

3.Gel coat consists of three parts: the gel coat itself, a catalyst, and a surfacing agent to aid in the curing process. The surfacing agent is required for open-air cure of the gel coat. In place of a surfacing agent, you can seal off the repair with wax paper or plastic film. This keeps air out to allow the gel coat to cure completely.

4.Apply your gel coat with a brush. Try to apply it as smoothly as possible. This will save you time on sanding after it has cured.

5.After the gel coat has cured, it’s time for sanding. Start with a 400 grit sandpaper and sand the repair nearly flush. Try not to sand too much around the surrounding areas, as you can sand through that gel coat! You can mask them off to help prevent that. Wet sanding works best. Gradually work to finer grits (600, then 1200) before finally buffing it finished.

For fiberglass repair

1.A good rule to follow is for every inch of damage there needs to be 12 inches of repair, a 12-to-1 ratio. If the damage is a puncture, hole, or delamination, remove the damaged area by getting rid of any loose material. If the damage is only stress lines you can simply repair over them.

2.If you are using the woven roving, one ply each of mat and roving is usually sufficient. If you are using cloth you will need two plies of cloth and one ply 1½ ounce mat.

3.Prepare the fiberglass by cutting some mat to fit and fill the hole. Also cut some the size of the repair 12-to-1 ratio. Cut the cloth or roving just slightly bigger than the mat.

4.Rough up the area to be repaired with sandpaper — 120-220 grit is preferred — this aids in bonding.

5.Clean the area to be repaired with acetone. This removes any contaminants and also reactivates the existing resin to help with adhesion.

6.Back up the existing hole on the outside of the boat with cardboard coated liberally with wax or plastic film. This helps to keep the proper shape of the kayak exterior.

7.You are now ready to laminate. Mix your resin and catalyst per manufacturer’s instructions.

8.Install the mat in the hole. Wet out the mat and the entire repair area with the resin using a brush.

9.Add the first ply of mat. Apply more resin to the mat. Roll with a small paint roller or fiberglass roller to remove any trapped air.

10.Add the next ply, cloth or roving and apply more resin. Lightly squeegee to remove any trapped air. Apply subsequent plies following the same procedure.

11.After the resin cures, sand any rough edges.

12.Now it’s time to repair the gel coat using the process above.


1.Resin. Please note which type of resin you choose to use. Epoxies bond to everything, but polyester and vinylester resins will not adhere to epoxies. Try to use the same type of resin the kayak was made from (vinylester for NC Kayaks).

2.Catalyst. The resin you purchase will generally have a recommended list of catalysts, most commonly an MEKP.

3.Gel coat. Trying to match color can be frustrating. UV rays can fade colors over the years, and even “white” may not look the same from manufacturer to manufacturer. Our advice is to try to be as close as possible, but accept that it probably won’t be perfect.

4.Surfacing agent or wax paper / plastic film.

5.Acetone. This is commonly sold as nail polish remover, but that often has artificial coloring and odors added.

6.1-2" paint brush, depending on the size of the repair.

7.1½ ounce fiberglass mat.

8.Either 6-ounce fiberglass cloth or 18-ounce fiberglass woven roving. The roving will build up thickness quicker than cloth. The 6-ounce will give a cleaner looking repair. Either will give a strong finished product.

9.Small paint or fiberglass roller.

10.Plastic squeegee.

11.Sandpaper in various grits.

12.Buffing compound.

Warnings / Tips

1.Find a warm dry environment. Sixty-five degrees is the minimum temperature you should attempt to do a repair in. But the higher the temperature the shorter your work time is.

2.Wear appropriate safety equipment, especially disposable gloves. Resin and gel coat are impossible to remove from clothing once cured. They can surely hurt your skin too. A paper towel with acetone — while it will dry your skin — will help remove drops.

3.Mask, mask, mask! You can save yourself a lot of headache by preventing drips, overzealous sanding, and errant brushing from causing problems by masking off nearby areas.

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What I would do

– Last Updated: Mar-08-16 9:11 AM EST –

I think the stern area could be taken care of with some pigmented polyester gel coat as you suggest. Evercoat sells a small repair kit with polyester resin, hardener, pigments, and a small amount of release film (as much as you would need):

You can probably get a reasonably close color match using the red pigment. Try to bevel the edges of the surrounding intact gel coat and remove any loose gel coat fragments. To fill in holes you will do better applying the pigmented gel with a plastic spatula or putty knife than you will a brush. Otherwise the instructions in the above post are good. If you use this particular kit, make sure you cover the newly applied gel coat with release film or waxed paper to make sure it cures properly. I have used this kit and it works fairly well, but no doubt there are many others that would work as well. Some kits have polyester putty or gel that contains wax that excludes ambient air and therefore does not need to be covered with wax paper or release film while curing.

You could also, of course, fill in the divots with thickened epoxy and sand the areas fair, then paint as Jack suggested.

Epoxy will work just fine on boats constructed with vinylester resins. I have done repairs on multiple Bell canoes, some quite extensive, using West System epoxy and it worked just fine. You can buy some vinylester resin if you like, but it has a limited shelf life, is more toxic, and will not work any better.

For the bow I would do something more than just apply some polyester gel coat. You have damaged fabric and a leak there. You probably know that if you use epoxy on an area, polyester resins like gel coat will not cure reliably over the epoxy.

I would fill in over the damaged fabric with epoxy (or whatever resin) thickened with silica gel powder (cab-o-sil) till flush, then wet sand it fair. I would then just go ahead and apply a thin abrasion plate on the stem consisting of one layer of 6 ounce/square yard fiberglass (S 'glass preferred). Rather than painting the plate to try to match the hull (which doesn't work that well in my experience) I prefer to add graphite powder to the epoxy used to apply the fiberglass plate and fill the weave of the cloth. I think the contrasting black color would look just fine on the red hull.

One layer of 6 ounce 'glass can be sanded very smooth and nicely feathered the edges and will stand barely proud of the surrounding hull. It will add negligible drag.

Here are some photos of a sunset orange Curtis Dragonfly that had similar damage to which I applied a thin abrasion plate as described above:

Never used epoxy before
Where is the best place to buy it? If I order it in a kit like this would that be enough?

Peter – you did a beautiful job on those skid plates. In my case, the bow is actually fine, its the bottom of the stern that has the broken gel coat. It must have come down off a drop onto a rock (or two or three). I was just going to put the fiberglass strip on the bottom and not bring it up the stem. I like the skid plates the way you did it, I’m just not confident that I can make it come out as nice as you did.

On the kit ; Yes
There should be a West marine store (no relation to West Systems epoxy) not too far from you.

I know there is one in Plymouth

You can also get kits at Advance Auto, and I have even seen them in Wally World in the Auto dept.

I go with West Systems, since they are high end quality

Jack L

Red gel coat
I ended up using red gel coat - it’s far from perfect, but at least it is water-tight. I may still add a fiberglass patch.


– Last Updated: Apr-23-16 2:16 PM EST –

650 is excellent for fiberglass repairs with enough time before not working even in 75+ temps on keel/stem protectors or single layer glass applications.

650 Thickened used on vertical surfaces in 75+ temps will wet fiberglass but a commercial spreader with extra hand pressure is useful.

I haven't tried a 105 mix suspect the advert info suggests use more than a few square foot of repair cloth.

West also $ells a $mall bottle of gelcoat for scratches n an inch of popped off gelcoat. Excellent results as a QnE repair of multiple gouges at the same time.

I tried Gumout as acetone after looking at the MSDS. I expected a residual surface coating but the repair is attached. Gumout was on the shelf.

The Rendezvous' skid plate kit from Wenonah was carefully masked with ? 3M masking tape, a tape curving well. The kit came with 650.

The epoxy runs 3/8th's past the skid plate felt boundry. Peel up the masking tape before epoxy cure please.

Fiberglass Patch
Added a fiberglass patch - not perfect, but it will do. I think I’m ready for the Moose River Bow trip on Memorial Day Weekend.

Actually, I’m glad it is on the bottom - no one will ever see my lousy work :wink:

First test
As much as I hated to do it, I’m glad I added the fiberglass patch. I put the first ding in it yesterday running this old broken dam - stern dropped down on a rock with a thud. Other than a little scratch, it looks fine.

not ready for Pebble Beach

Frayed edges…

– Last Updated: May-09-16 6:21 AM EST –

Yeah - I brushed some of the edge fibers out to the weave when I was applying the epoxy. Dab, don't brush on the edges. I remember that now. Good news is that you don't see it when the boat is in the water. ;-)

A carbide scraper…
…will make short work of the edge fibers. You can get one a any of the big-box stores.

TBH, my work is frayed. Your rusty rocker panel reminded reading HOW TO before the next setup is best.