Marine-Tex for filling holes in the coaming?

Sep 30, 2013
3,596
1988 Catalina 22 North Florida
I've never used Marine-Tex before. But I have some on hand, and I have some holes in the coaming, and I'm thinking about putting the two together.

I like the idea of thickened epoxy better, but then I have to re-gelcoat over it. Which I'm not against, actually, if that will result in a less noticeable repair? But I've never done that before either, so I'd be curious about what kind of gelcoat to use and how to use it.

Am I rambling? :redface:
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
I successfully used Marine-tex for that type of repair. Placed masking tape behind the perforated laminate, mixed up the epoxy putty and pushed it into the holes, leaving the surface slightly recessed. Into this recess I was able to apply a thin layer of colored gel coat repair that was entirely durable. Doing the same repair in gel coat alone resulted in failure - no strength or flexibility.
 
May 11, 2004
273
RAPTOR Hotfoot 20 Ghost Lake
I work at a marina and we use it all the time.
Mask behind like Gunni says but we also mask around the front of the hole . Saves a lot of sanding. We remove this tape right after we've finished filling. Don't wait for the Marine Tex to set.
 
Nov 9, 2012
2,500
Oday 192 Lake Nockamixon
For screw/bolt holes, I would use a countersink to bevel out the sides of the hole. The Marine Tex will stick in there better. Sure, it'll make a bigger hole, but you'll probably get better results.

Also, try to cut back and sand the Marine Tex before it is fully cured hard, otherwise it becomes extremely hard, and you'll never get it to sand flush with the gelcoat because the gelcoat is so much softer.
 
Oct 26, 2008
6,295
Catalina 320 Barnegat, NJ
It is a very durable product and made for what you describe, but as Brian says, it won't sand flush with the gelcoat easily because the gel coat is much softer in comparison. I've yet to make a patch with marine-tex that didn't leave a raised area (and the color rarely matches either). If you are very fussy about the appearance, I think it is a difficult product to blend with the gel coat, at least in my limited experience. It will provide a much stronger repair, though.

I've heard that gel coat won't bond over epoxy. The answer is a little more specific though. Polyester gel coat will bond to properly cured epoxy, but if the hardener mix is not done correctly, it can be an issue. An epoxy gel coat may be a better finishing material afterall.
 
Feb 26, 2004
23,055
Catalina 34 224 Maple Bay, BC, Canada
Scott's right. One trick I've used is to place saran wrap over the visible side of the MT, makes it shinier rather than dull. It won't last forever, but is a good fix, unless you go the gelcoat route. Depends on what you wanna see.