Repairing gelcoat on kevlar canoe.

I am looking for a book, or better still a video (youtube is fine) about repairing cracked gelcoat on a kevlar canoe for dummies - meaning yours truly. Something like (1)chip out the crack. (2) mix the gelcoat. You know - for dummies. Any and all suggestions would be greatly appreciated.

I just use epoxy. Very simple fix.

no biggie


Gel Repair

– Last Updated: May-23-15 9:59 AM EST –

Most gel coated hulls are constructed with polyester gel, and, hopefully, a good quality vinyl ester stabilizing the fabric layers.

If the damaged hull is constructed of epoxy, like Souris River, an epoxy patch makes sense. If the hull is pretty clapped out an well down the path of becoming someone else's fishing boat, epoxy surface patches are easy, the material easily acquired and any problems not worth consideration due to the relatively low remaining value in the hull.

If the hull is in pretty good shape, it is worth the effort to not introduce another chemical compound family that may compromise later repairs into the hull. Epoxy patches generally do not bond with subsequent poly or vinyl ester repairs. For such hulls, hre's one version of the proper process.


Gel coat is a glossy abrasion resistant finish protecting the paddlecraft's structure by absorbing shock and scratches. It should be cleaned regularly to maintain appearance and prolong useful life. Frequent 303 treatments keep your boat bright and slippery.

Scratches and repairs in gel-Coat may be wet sanded out - starting with 120 grit dry paper and progressing through 320, 600, 1000, 1200, 1500 and 2000 wet paper before finishing with rubbing compound, and hand glaze or polish. Use a foam sanding block and lots of water, being careful not to sand through the gel coat. After polishing, treat the area with 303.

Clean the area of damaged gel with acetone, then dry. Pick out cracked gel, removing all fragments. If fabric is exposed, break the surface with coarse sandpaper. New gel bonds better to sharp edges; coarse sand only if needed. Then wash with acetone and let dry again.

Gel Coat, clear or pigmented, is a polyester resin and must be catalyzed to harden. For a complete cure the canoe must be kept above 70 degrees F and 50-60% humidity for 8 hours. To repair Gel-Coat, wear a plastic apron and rubber gloves in a well ventilated work area. Use a discardable container and measure and mix MEK catalyst as in the chart. Improper catalyst mixtures will not cure, so measure carefully and stir thoroughly! Average working time with this mixture is 15 minutes @72dgF.

GEL COAT VOLUME 1/2 Pt / 1/4 Pt / 2 Oz / 1 Oz / 1/2 Oz / 1 TBS / 1 tsp.
MEKP 9 VOLUME / 2.5cc / 1.2cc / .6cc / .3cc / 2 drops / 1 drop

The gel coat/catalyst mixture will not change in appearance or viscosity for nearly 10 minutes, but hardens in 20. Spread the mixture over the damaged area with a flat stick, making sure the gel is “proud” to eliminate the need to recoat. A drafting tape dam can keep it from spreading.

After the gel hardens, evaluate whether another application is needed. If not, wipe with acetone a few times to remove residual styrene and sand the area to original shape and gloss as described in the second paragraph above. Finish by applying 303, which resists UV degradation, protects from scratches, and eases scum and road oil removal. Paste waxes are less helpful, protecting the hull from scratches, but attracting road oil and slowing the hull on water.

NOTE: Gel-coat shelf life is 30 45 days! Use immediately! If your gel coat is too thick, thin w/ MEK, a high-end paint thinner. Thinning with acetone changes gel times.

WARNING: The manufacturers of these materials advise they should be used only under the following conditions: Use adequate ventilation and keep away from open flame. Protect yourself from prolonged breathing of vapors and contact with skin; keep away from children. If any material contacts your skin or eyes, wash immediately with water and call a physician.

Same here
If it is just a small crack or hole.

Sand it. Then clean the area with acetone.

Mix up some two part epoxy, and put it on.

Tape a piece of stiff clear plastic film like overhead projector film over the area while it is still soft.

The next day, take the film off and you should have a glass like finish. If you didn’t use enough epoxy and have an indent, just do it again.

Use a high end spray paint such as Valspar that matches your color, but mask the surrounding area so you don’t get the mist on other colored areas.

I have done this many times on the gel coat hulls of our kayaks

jack L

I have a tutorial on my site

– Last Updated: May-23-15 10:00 AM EST –

It's a demonstration on a kayak, but the priciples are the same regardless of the type of boat.

There are a ton of instructive videos on the subject on youtube and maybe some other places. There will be some variations, but they all work.

In my opinion, the first step should be to find out what type of gel coat is used on the boat via the manufacturer.

For a first-timer, the detail instructions might seem complicated and somewhat daunting, but in actual practice it is all quite simple and the results are that the boat will look and be just like new if you stick to the instructions–step by step. I found the instructions provided on to be most useful.

crack repair
The simple thing to do is find some good quality body filler pre-mixed at an auto body paint store. Sand it smooth and paint it. Canoes are made to be used.


– Last Updated: May-24-15 9:30 AM EST –

kind of funny...Gel coat is about the same and a better product for this fix. Everyone seems to think there is some sort of magic involved with Gel.

Just get some fresh Gel add hardener, fill the prepared area, {I spray with PVA to seal out the air because I always use non-waxed Gel} Then let cure some...Sand...then buff...non much difference what you use...but Gel is like material to what you are repairing and so any further repairs aren't complicated with contamination of dissimilar materials {and it can also be color matched}

Best Wishes