Repairing a deep scratch in the hull

[Moondance]

I have a couple of deep gouges in the hull on the black strip at the water line.

It's through the gelcoat and into the fiberglass. It's not a crack at all..just a good deep scratch. ( approx 2 1/2 - 3 inches long )

I'd like any advice on repairing it.

The fellow at the local hardware store ( with a boating department ) thought a 2 part epoxy would be best to fill it in, then just touch it up with paint, and then sand or buff to blend in. He said that Gelcoat ( mixed with some fibers or a thickener ) wouldn't last more than about 2 years and would then fall out. He said that gelcoat doesn't stick well other than when initially applied in the mould.

Any feedback would be appreciated or link to sites.

thanks

[DLT]

I've repaired a gouge like that with Marine-Tex. You should be able to find it at any local marine store. I wouldn't buy it online, if only because the shipping charges would be relatively high...

It is pretty easy... Just take the warnings seriously and use disposable gloves...

My gouge was in the white area, and I used their brightest white (apparently there are shades...). I don't know if they make a black... If not, then paint may be the way to go...

[Scott]

I disagree that Gel coat doesnt stick well. It sticks better than paint when applied to fiberglass. The trick is to sand/ rough the base and clean it well with acetone.

If your scratch is deep enough fill it to just below the hull level with a marine filler/ bondo. Not car stuff as it is absorbant. Then use multiple coats of Gel to bring the level SLIGHTLY above the desired level to give you sanding surface, craft brushes work well for filling scratches without getting it on the surrounding finish. These can be stolen easily from your children if you have any. On your final coat cover with acetate (Plastic wrap) as Gel coat wont completely harden when exposed to air. 240-4-600-1200, polish. done

On Edit and big afterthought Some paints will perform as well as Gelcoat and be easier to use. Surely the official board engineers can explain this better than me but.... my company deals in the transport of liquids. One of the commodities we move is epoxy. It is our 2nd largest mover. The largest shipper we move epoxy for has 1 product remember that number ONE. Same C of A, same blend. It comes from Taiwan.

Now the important part. We deliver this product to (blank) polymers, which makes industrial glues from it. We deliver some to (blank) composites and polymers, which makes epoxy paint with it, you may have bought some at lowes or HD or it may have helped you hold your lane on the highway. We also deliver it to Marine (blank) that makes resyn for marine applications with it. Some goes to (blank)tech they make industrial resyn from it this is used in the roto molds that make the carbon fiber booms on the high tech cherry picker trucks you see the phone coompany use.

Thats the short list. With the exception of some chem blending magic, same base. Do your home work and dont just go for the same color at the corner nut and bolt store. Buy the right product and you'll be happier in the end!!

Peace

BTW, pull out the phone book and fill in the blanks and you've prob got the right companies.

[Night Sailor]

The same place that sells fiberglas repair kits or gel coat also sells pigments to add for matching whites, black, or any other color. Mixing is easy. So why not do the repair with the correct epoxy and in the correct black color?

[Richard O'Brien]

Moondance. I believe Nightsailor has it right. I work with epoxy fairly often making molds. There are no situations I've experienced where Polyester resin was as strong or adhesive as epoxy. Polyester gelcoat shrinks after it's applied and pulls away(microscopicly) from the abraded surface. Epoxies have less shrink, and are slightly tougher so they don't pull away much. Urethanes are so tough & flexible that they can't be removed often (Gorilla glue), but they lack epoxies strength. Silicons have their own lubricant, and nothing sticks to it, including itself after curing. There are some new epoxy-urethane hybrids coming out that may be pretty indestructible.

[Frank C]

Don't forget the "Featured Articles" page of Heath's website.

One of those was written by Steve K, former Mac owner, former collision repair guy and former Corvette guy (biography strictly from sketchy memory). Anyway, Steve's article gives a very detailed account of the steps to follow in a FRP repair. It's vastly more comprehensive than possible in a post.
Good luck!

Here is a step by step for repairing scratches in gelcoat. This would apply to deeper and/or wider scratches, where the raw fiberglass is showing through. ... With a little practice, you should get very professional looking results, using these steps.

(see remainder in "Repairing Gelcoat," under Featured Articles)

[Tom Spohn]

Order a jar of Paste patch from BWY. After applying to a clean surface wet sand then wax.

[Rich Plumb]

Unfortunately Macgregors don't come with training wheels. I agree with Tom Spohn. During the first couple of years, I used a lot of that gel coat patch from BWY on some pretty big gouges. It worked fine and is still on there after six years.

~~~~~~~~_/)~~~~~~~~~~
Rich Plumb "Plumb Crazy"
Covington WA 26X

[Ron]

Last year I repaired about 10 shallow scratches (only in gel coat) and 2 deep scratches (down to fiberglass). For the shallow scratches I used a gel coat repair kit. I relied on the instructions in the feature article on this site. For the deep scratches I used MarineTex.

A good repair seems to take time (cleaning, sanding, filling, drying, sanding ....). I got all the grades of sand paper to very fine sand paper. Also don't be cheap, get a sanding block.

With no experience I was able to get some of the repairs to look as good as new.

Good luck and take your time. Fiberglass is actually very forgivable.