Hairline Crack On Fiberglass - Best Way To Repair

[Rusty Axle]

My '06 226 has some hairline cracks that I'd like to repair on the left side gunwale.

I've done auto body work and painting, so I'm familiar with the process of making finish flaws disappear.

What is the best product to use for permanent hairline crack repair in white gelcoat?

I recently purchased the boat and just noticed the cracks, so have no history on what might have caused them.

Indiana had an extremely cold week in winter '22, so it's possible that was a factor. Or, possibly something very heavy impacted or was resting on the area. I can't imagine it being due to structural stress.

Thanks for any help with product suggestion.

[jpwhit]

https://spectrumcolor.com/

Spectrum sells matching gelcoat. But you'll need to use something like a Dremel tool or router to grind out a v-grove where the crack is.

[Scooter G]

jpwhit nailed it (as always), lol.
Cause? It's gelcoat and a boat taking on constant abuse and pounding from the elements.

You are in tight spot there with the crack running into 2 different contoured areas. Very light v-groove, and a little light roughing with sand paper just outside the crack (start with the folded edge of maybe 400 grit), just enough to get the gel to bite & adhere. You are fortunate it's white, and it's a small line, easy to match. Evercoat makes a good product for small touch ups. Run an off the boat test with the gel to make sure you get the hardener mix ratio correct for your ambient temperature (Much like body filler or Bondo). If it cures hard in an hour, you got it about right, much less than the you might be a little hot. If it's still gummy sticky after an hour, well, you get it. After you have applied to the boat, and cured, it's just a patience step down in sandpaper steps from there. I would start widening the sanding path outside the area when you get down to the wet 800/1000 grit. I usually work down in steps and finish with wet 3000, and then bust out the compound and buffer. Gel goat is soft, and sometimes it's better to take longer on less aggressive sandpaper i.e. 320 grit can leave some pretty gnarly scratches outside the repair area. Remember patience, and with your prior experience, you'll be an expert in the arena. It's pretty hard to screw up, your worse case scenario is you have to do it twice to a bigger than you started with area, not that I know anything about that.

They also make some purdy cool vinyl stickers that will cover the spot nicely, you know, like Ronix, Hyperlite, Liquid Force...

[Rusty Axle]

Excellent. Thanks for the guidance!

[jkallen21]

Great suggestions so far. I'd add that you should test the process on the rail under the rear storage cushions or some other place you can't see

[biacs]

I had a quarter size chip taken out of the nose when someone pulled the boat into the dock too hard. I used a local company franchise 'miracle method'. He matched the gelcoat and fix the chip perfectly.

If you could grind those cracks open, they can apply the epoxy with a color match to it and buff it down. But it takes a little creativity from thetech :-).

My repair turned out perfect! I had to repair a bathtub chip and he worked on the boat too!


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[gary s]

In the first picture that crack could be caused by that screw. It's caused by the screw lifting up the gel coat. It needs a taper / countersink through the gel like this \ / rather than a straight drilled hole. Correct Craft over the years have upped their game but maybe they missed one or it's not tapered enough. I've seen early 90's boats where they did not do it on rub rail screws, there can be cracks straight up the deck from the rail in numerous spots. The last pic just looks like the rub rail hit a dock and cracked the gel should be an easy repair too just will have to remove the rub rail and grind down and fill the complete crack. I have found that a Dremel 9906 bit works well for grinding a taper in the original. You will discover that trying to get the gel color match is the hardest part of the whole job. Check with Spectrum for a 2oz kit,it still might need to be adjusted but it gives you somewhere to start. The silver cloud kit for my 95's hull was a little too dark. In the pictures below a PO had put a single lever control into my 69 Mustang, when I put it back to original I had this big hole to fix. As I said the hardest part is the color match especially something that old where the color has faded and has no off the shelf match. Clean and buff your hull before you try to match and make enough so you won't need to do it again

[Scooter G]

Nice skills gary s!

[Rusty Axle]

Nice work, Gary!

The Silver Cloud 03-06 gel kit from Spectrum Color is out for delivery today.

What was your process for a perfect color match?

[gary s]

Sorry it took so long to answer, been on the road- Mine was too dark but since it was right under the chine I did not bother. Titanium oxide would lighten it up something like this- https://fiberglassflorida.com/10x30-white-pigment.html