Watertight Epoxy Filler ???

[Bob Pullen HC-33 1981]

Got a couple divots (dry, not blisters) on the bow/hull, which need addressing before a couple coats of bottom paint. Saw a website that talked about using "Watertight Epoxy Filler". Is that equivalent to using West marine 2 part epoxy with one of their fillers added (404 407 etc) ??

Many thanks
Bob
S/V Seanorita
Yucatan, Mexico

 

[sailingdog]

It be about the same as using Marine-Tex or West System with a cabosil or fumed silica filler.

Don't use the microballoon filler, since once sanded, it absorbs water, as does the wood flour...

Try and get either the Marine-Tex or the thickened West Epoxy as close to fair as possible, since both are a PITA to sand. The West System will definitely need paint or gelcoat to protect it from UV... the Marine-Tex not so much..

 

[sailaway78]

Marine Tex

My vote would go for Marine Tex. Pretty amazing stuff, and should do the job nicely. Just mix and apply. Like sailingdog says, get them as fair as you possibly can, because they are a real bitch to sand.

 

[higgs]

I have always used the West System in these applications with good results.

 

[Maine Sail]

You've had good advice..

You've had good advice the only thing I'll add is this.

I usually use epoxy for jobs like this but when you fill a divot with epoxy just know that when it cures it will be harder than the surrounding gel coat. If you just attempt to sand it all flush you'll wear away the surrounding gelcoat faster than the new thickened epoxy. Hope this makes sense?

One trick is to either use a razor blade or a very sharp chisel to very carefully shave it as flush as possible then try your best to apply the most pressure to the new epoxy as opposed to the surrounding gelcoat to feather it in with sand paper. Sometimes it's easier to use 3M Marine Premium Filler (LINK).

3M Marine Premium Filler is a vinylester surfacing putty designed for fixing surface defects and because it's a vinylester it is much safer for use below the waterlne than a polyester based fairing putty like Bondo or some of the polyester Evercoat products that can eventually saturate with moisture.

Either epoxy or a vinylester like the 3M Marine Premium are the preferred below waterline fixes but the 3M vinylester sands and feathers at a closer rate to your existing gelcoat.

 

[ITMaster]

Would This 3M Filler Also

Be a preferred product to use for minor dings or nicks in the Gel Coat above the water line, Maine Sail? Or should one just go with the gel coat repair products and try and match the color as best they can? I had someone asking me about this the other day, and since I didn't have any experience in repair of this nature, I couldn't offer any help to them.

 

[Maine Sail]

Re: Would This 3M Filler Also

Be a preferred product to use for minor dings or nicks in the Gel Coat above the water line, Maine Sail? Or should one just go with the gel coat repair products and try and match the color as best they can? I had someone asking me about this the other day, and since I didn't have any experience in repair of this nature, I couldn't offer any help to them.

Yes you could use it but I prefer epoxy because for cosmetic fixes it is more stable and tends to shrink less..

For small scratches or dings I prefer to fill the gouges with cabosil thickened epoxy that is tinted with white tint. This prevents any bleed through to the new gel. I then Dremel the thickened and tinted epoxy back ever so slightly back below the surface of the gelcoat. Next I mix up the gelcoat and apply it with an artist brush building it higher than the surroundings. Once kicked I shave the top of the gel flush with a sharp chisel or razor blade being very careful not to "gouge" the surface. (this is more art than skill) Once nearly flush I wet sand (fresh gel is usually harder than old gelcoat to sand out like epoxy) focusing on the new gel as much as possible. When I get to a P800 or higher I buff and polish it up.

If your really good with color matching, I'm not so good, you won't be able to see it. You can send out to Mini-Craft in Florida for exact gelcoat matches if you can send them a chip or hole saw plug to match.

 

[moparv104x4]

Re: Would This 3M Filler Also

Watertight is a very easy to use 2 part system that will not absorb water. It is best used under the waterline because of its turquoise blue color it needs to be painted above the water line. As under water surfaces are painted with bottom paint it is not an issue. It is real simple to use because it is a 1 to 1 mix and you can fill up to ¾” with out sagging. It is easy to work with and easy to sand if you do the sanding within 24 hours, after a week or more it gets very hard. Over the last two years I have used it with success on several under the waterline repairs on my 1981 Islander B30. If you are not comfortable mixing epoxy resin and thickening it Watertight is the product for you.

 

[Zaphro]

I've had very good luck with Interlux products, including Watertite.
Here's a link to their product data sheet:
https://secure.international-coatings.com/pds/yacht/GB_ISO_I_5000188.htm

 

[Bob Pullen HC-33 1981]

Many thanks for all the very helpful and educating input!
Bob

 

[Jim]

I used Marine Tex to repair some cracks in my keel and the stuff worked GREAT! Two years later and it is still holding up.