Epoxy with pigment instead of gelcoat

[hd002e]

I am curious about the longevity of my latest invention: mixing epoxy+adhesive filler+art supply store pigment into a batter to coat epoxy repairs instead of gelcoat.

I have had unexpectedly good results using west systems epoxy with their adhesive filler to plug machined holes and such on my fiberglass boat over the years. The first repair I made about 10 years ago still stands strong and did not crack, fade or yellow even after constant exposure to Sun’s UV. I know the epoxy repairs dont look finished compared to what you can do with gelcoat and paint but I swear I will get around to touching them up with paint one day... Recently I picked up some white pigment powder from an arts supply store and have been mixing that in with my epoxy+filler to improve on my technique and if I may say so it looks pretty good. I am curious how it will stand the test lf time.

Has anyone tried this? I will post aome photos tomorrow.

[Thumbs Up]

You do know that west system sells their own (liquid) pigments right? I would look into buying some titanium oxide powder (maybe that is already what you have) for the experiment. I have had good luck with epoxy primers in the sun, they yellow but only on the surface. The easiest to use (stays where you put it and easy to sand) filler that I have found is industrial talc with a small amount of cabosil. People used to use baby powder but most baby powder no longer contains talc. Marine tex seems to hold up pretty good in the sun but is expensive and hard to measure (without a scale).

[roverhi]

Epoxy deteriorates under UV exposure. Mine started breaking down within a year of coating the cap rails and is all gone after 8 years. If the colorant doesn't give UV shielding, it won't last very long at all.

[GordMay]

Originally Posted by Thumbs Up

You do know that west system sells their own (liquid) pigments right? I would look into buying some titanium di-oxide powder (maybe that is already what you have) for the experiment. I have had good luck with epoxy primers in the sun, they yellow but only on the surface...

West System additives & pigments do NOT provide UV resistance, they "improve epoxy’s abrasion resistance or moisture resistance".
West System does NOT offer a TiO2 pigment.

West System on Finish Coatings (UV)
"... Two-part linear polyurethane (LP) paints offer the most durable protection available. LP paints are available as pigmented or clear coatings and offer excellent UV protection, gloss retention, abrasion resistance, plus compatibility with epoxy. However, compared to other types of coatings, they are expensive, require more skill to apply and present a greater health hazard, especially when sprayed..."
➥ https://www.westsystem.com/instructi...nish-coatings/

West System Additives & Pigments ➥ https://www.westsystem.com/the-105-s...ives-pigments/

Titanium dioxide is a well-known white pigment; but beyond its exceptional whitening power, it can also increase the durability of a paint. TiO2 has a positive effect on the weather resistance of a coating due to its UV absorbing capacity. TiO2 absorbs UV light, which provides protection from UV degradation to the underlying resin molecules. After UV absorption, however, the energy of the UV photon must be transformed to another form of energy. In the clear majority of UV light absorption events, the energy absorbed by the TiO2 is changed into heat, without damaging the paint film. However, the UV light energy is sometimes changed into chemical energy in the form of chemical radicals. These radicals form on the TiO2 surface, but are mobile enough to travel to resin molecules, where they initiate a series of degradation reactions that ultimately lead to film failure. This process is called photocatalysis.

[boatman61]

I have used West System epoxy with their pigments and the worked great..
Did my Tiki 21 using the black pigment and the beams with clear epoxy with great results.
Was still looking good when I sold her 2.5 years later.
Word of warning on teak cap rails/decks etc.. epoxy does not like oily woods and starts yellowing and bubbling in no time.

[Thumbs Up]

I have done a lot of epoxy projects with teak. Not clear coating. I epoxied and awlgripped all of my teak grab rails. I installed a teak strip floor over the ply on my cabin floor. The trick is to rough it up good but more importantly to rub as much of the oil off with clean rags and plenty of acetone.

[AJ_n_Audrey]

Originally Posted by roverhi

Epoxy deteriorates under UV exposure. Mine started breaking down within a year of coating the cap rails and is all gone after 8 years. If the colorant doesn't give UV shielding, it won't last very long at all.

Same experience I had. The epoxy on my rails lasted maybe two years. I sanded it off this year.

[Atlanticsailing]

I plan to strip the existing varnish and replace it with clear epoxy over a topside plank known by various names -- the "fish plank," "cap rail," sheer plank, etc. Regardless of the name, this mahogany plank runs fore to aft, and sits on top of the the lower wooden planks of the hull. It is a beautiful accent and of course fully functional. The rest of the hull is wood, professionally coated with epoxy and sprayed with Awlgrip.

The fish plank is fully exposed to UV, salt spray and whatever comes down with the rain.

So the big question is: How many years of clear, sharp, 'freshly done" look can I expect from the epoxy before yellowing or other deterioration vs high quality varnish? The work will be done professionally, by a true epoxy guy, not a yard guy reading directions off the can. (No disrespect meant.) Anyone out there who has made such a comparison?

Thank you. "Whisper" is a 36' yawl, Rhodes design, built by Abeking & Rasmussen, Germany, in 1956. Very sound, good dry old growth mahog planking.

[Atlanticsailing]

Correction: The plank in question is mahogany, not teak. (On "Whisper" the hull is mahogany, while the deck and cabin are teak.)

[Don C L]

I've had good luck with white marine-tex and I just noticed a reference for coloring it yesterday at the chandlery strangely enough, but where to get the pigment I don't know. Interesting idea, try calling Marine-Tex I guess. West Marine has their own version of marine tex too, try giving them a call too. I am using it for patching some holes before painting but I have some that has been exposed for years and it looks fine.

[Thumbs Up]

You will still need to coat it with several layers of varnish over the epoxy. There are other 2 and 3 component products though such as Bristol finish and Awlwood that might be a better choice. With just epoxy it will depend on the amount of sun it gets. West 207 special coatings hardener has a UV inhibitor but still needs varnish over it.

[guyrj33]

West System epoxy without additives or pigments will quickly yellow and fail when exposed to UV.
When mixed with filler and pigment it can last for decades exposed to UV. I have some small holes filled on deck with West epoxy, high strength filler and aqua blue green pigment. The patches are over 10 years old and look great.
The other way i've used epoxy on deck it to clear coat teak before varnishing. As long as you start with 6-8 coats of varnish and re apply every year it works well. But let your varnish go and the epoxy will soon yellow and fail.
West does list their aluminum barrier coat additive as having UV protective properties.

[Cheechako]

Beware that epoxy degrades in sunlight. The pigment may help some. How much I'm unsure.

[sailortype]

slight thread drift but a fellow passing through our marina coated his hatchboards with epoxy as a sealer and then several coats of Helmsman's Varnish... he had just spent five years in Florida and they still looked great. I was thinking od following suit... any experience with this?

[sailortype]

teak... hatchboards