Gelcoat Repair, Gelcoat Repair
(by Sea Scouter)

Just like golf is a simple game (it's only direction and distance, right?), so is gelcoat. It's only color and surface finish. The color is the tough part, but a good finish will mask the color mismatch.

Here's what I have had good success with...

1. Dremel out the wound to remove all the little baby chunks that weren't removed when you hit the dock.

2. Fold up a little piece of 80 grit and rough up the surface of the scar.

3. Wash out area with acetone, twice. Use a fresh paper towel each time.

4. Use a gelcoat paste, available in marineshops. In kit form it has the colorants. You might have to buy and extra white tube of pigment. Check date on tube....

5. The real "step one" is to mix some gelcoat samples. You will most likely do a half dozen samples with different colors before you're remotely satisfied. White is rarely "white". Try a pinhead of black, or yellow to tint to the "old" gel on the boat. DO NOT OVER HARDEN! If it says 3 drops, six drops will only soften the batch.

6. Step 1-B is to fold the little samples in waxed paper or mylar. Squeeze out any air bubbles and seal with masking tape. You must seal off the gel from the air. Gelcoat is "air inhibited". Twelve to twenty-four hours later you will have some color chips. You just have to remember if the good sample had the pin head of black or the pinhead of red???

7. Back to the boat. Mix your gelcoat, like the good color sample. Pot life is very long because it is not sealed off from the air. Squeegee in the gelcoat to the offending area. Overfill. (Another good method of "overfilling" is to place several thicknesses of masking tape as a border around the repair area. Keep dabbiing until you have eliminated the air bubbles. The texture will be like soft butter. If you are careful, you may be able to fill an area as deep as 3mm. If the area is more than 3mm deep, consider a coat of epoxy filler first. Anyway, keep the gel repair "higher" of the hull surface.

8. Carefully place a piece of mylar (this is the plastic backing material that sign shops use, you can find it in their garbage cans) over the repair area. I like the mylar because it is translucent (you can see bubbles) and it is a little stiff, making the repair flat. Don't press down, just work out any little bubbles to the edge by sealing one, then two, then three, and finally the forth edge off with masking tape. Kiss the boat good night. In cold weather, duct tape a heating pad over the repair covered with bubble wrap.

9. IMHO, finishing is more important than tinting. Buy a sanding block. Never sand on the hull with your fingers. The 3M red block is the hot setup. USE ONLY "WET OR DRY" PAPER and put a drop of dish washing liquid in the bucket. Pull off the mylar. Hopefully, the repair gel is highter than the hull. Get the level of the overfill down starting with 400, then 600. Keep the area wet with your soapy water. Polish off with 1000, 1500, or 2000. A nice progression up the ladder will save time in the long run with the buffer. After sanding, buff out with a little machine cut buffing paste.

From a practical standpoint, if you get the finish correct, the repair will look very good. Even if you are a shade or two off in the color, you will not see the repair from 10 feet, and you will never see the repair when the boat is in the water.


If you have a production boat, I would definitely check out
http://www.minicraft.com