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Varnish over Epoxy

PostPosted: Thu May 10, 2018 7:35 pm
by Tim C.
I am in the process of reviewing some of the Marine varnishes to apply over my epoxy/fiberglass skin. There is a lack of head to head comparison amongst the various types of tung oil/urethane finishes, and the various UV resistance components.
Is there any feedback from members on success or failure with products such as Epifane, Interlux, LeTonkinois, Zspar or Petit? For example any spalling or flaking after a short time, amount of sun the trailer sees, how many coats were appliess?
Thanks

Re: Varnish over Epoxy

PostPosted: Fri May 11, 2018 12:11 am
by QueticoBill
Well, I recoated my kevlar and epoxy canoe with epifane and its been great. Obviously in sun while tripping but stored in garage.

Re: Varnish over Epoxy

PostPosted: Fri May 11, 2018 8:04 am
by swoody126
most of the above mentioned "marine" finishes will provide a reasonably good result

the issues experienced by most who complain were caused when they did not do their due diligence when it came to SURFACE PREP

the BLUSH must be addressed and totally eliminated

then the entire surface requires fine sanding

sanding involves scratching(minutely) the ENTIRE surface to the point where it has changed color to a chalky grayish/whitish color(indicating there are no unsanded spots remaining) and smooooooth to the feel w/ the naked hand

¿ did i mention SANDING ?

once sanded several(3+) coats of varnish applied according to label instructions will provide UV protection

some products require specified curing time + sanding between coats

some work well when HOT COATED(additional coats applied within a specific time window which is prior to complete curing and w/o sanding between coats)

NOTE: some epoxies on today's market have UV inhibitors already in them CHECK WITH THE MANUFACTURER

using UV inhibiting epoxy could save you a substantial amount of work time & $$$...

the attached pic was taken after the solid mahogany and edge grain marine fir plywood were sanded down to the wood and 2 coats of UV inhibiting epoxy were applied using the HOT COATING method(after sanding the total coating time was less than 24 hours)

sw

Varnish over Epoxy

PostPosted: Fri May 11, 2018 10:58 am
by KTM_Guy
I have used West Systems epoxy with 207 hardener and Epifane on some outdoor furniture.

The epoxy only has shown some failures on sharp edges after two years. West System says to use a good varnish with UV protectors. The epoxy with Epifane gloss over it (at least 5 coats) looks like the day I did it. It’s had a full summer and two winters so far. The stuff I’ve done with just Epifane still looks looks good as well, but it is in a different area and doesn’t get as much sun.

This is in Masa, AZ on my roof top deck, so it gets a lot of sun and heat. Not much rain but when it does rain it can be hard. The other area is on the covered patio and gets full sun till noon.

I first used Helmsmen Spar varnish and it was a failure after the first summer.

Todd


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Re: Varnish over Epoxy

PostPosted: Sat May 12, 2018 11:45 am
by Nobes
I took mine to a body shop & had them prep it and clear coat it. Should last 20 years. I’ll be 77 then. Very, very happy with the result.

Re: Varnish over Epoxy

PostPosted: Sun May 13, 2018 7:07 pm
by Tim C.
I have been using West System epoxy for many years and am pretty satisfied with it. On a sea kayak I made, I had sanded it down finely and used Perfection Plus, but it is a pain to handle - though the finish is hard and stands up well. I would prefer something where I didn't have to sand between coats. Candidates so far are Pettit Z Spar Flagship, Epifanes, Interlux Schooner - pretty much all tung oil/phenolic with UV inhibiters and not the urethane type.
A bit of a price range so may talk to the Yacht supply company locally too in case they have sale on any of these. Thanks for the input.