Varnishing over epoxy top decking

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Varnishing over epoxy top decking

Post by Kelsey » Sat Jul 26, 2014 8:46 pm

Im nearing the stage of finishing the decking and trim work on my Glen L 15. I was thinking epoxy then varnish. Is the epoxy nessecary?
I thought just varnishing would be easier to get a really smooth finish. My only concern is the spill out of the epoxy when gluing trim work would show through. So i was thinking to epoxy everything to blend it in then varnish. Any thoughts would be appreciated. The epoxy is just tough to get smooth i find on the plywood. Not as much on hardwood is seems.

Thanks, Kelsey

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Re: Varnishing over epoxy top decking

Post by Roberta » Sun Jul 27, 2014 4:49 am

You can varnish over epoxy coatings, but let the epoxy cure for at least two weeks before varnishing or the varnish will not harden up and will react to uncured epoxy. Personally, for decking, I would just varnish. If the spill out of the epoxy is transparent, you will not see it due to the amber color of the varnish. If it is opaque, then try to scrape as much as possible off.

Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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Re: Varnishing over epoxy top decking

Post by Stuart » Sun Jul 27, 2014 10:12 am

I put a layer of epoxy on everything including some with glass. What you say about smooth is often true. Epoxy has some odd reactions to standing water and incomplete mixing. It definitely needs to be clean and sanded before putting anything over it. However, it seals everything and being a glue, it binds everything really well. It forms a meniscus edge which prevents water getting under things and pulling the seams apart. I had some of the epoxy lift over the winter but its fairly easy to repair by just taking out the bad area, pouring in more epoxy and then sanding smooth. To get that kind of depth with varnish is going to take a long time. Epiphanes is really good paint but it must be put on in thin layers and to get the depth of epoxy is going to take months to dry enough after each coat to sand. I will put one maybe two coats over my epoxy and have the depth I need. But you're right, epoxy will lay a little wavy but you must long board it where it's needed as you see it necessary. The final coat will always be varnish and if you're outside like I am, its a real treat for the bugs because it takes so long to dry.


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Re: Varnishing over epoxy top decking

Post by cusoak » Mon Jul 28, 2014 5:47 am

I think the epoxy is not necessary on decks. I have just used high build varnish firs to build up coats faster. scuff sand in between coats. Sorry this is after you have sealed your stain. About 7 or 8 coats then led dry good for sometime. Then flat sand and start with a good finish varnish. I did this on my Zip and am doing it on my 66 Century Resorter.

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Post by Merxnavy » Mon Mar 28, 2016 1:38 pm


Ive heard of various levels of trouble regarding getting the old board remnants out and the new one in. What was your experience?

I have gotten several good

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Re: Varnishing over epoxy top decking

Post by Mike Worrall » Mon Mar 28, 2016 3:22 pm

If you do use epoxy, you must remove the amine blush prior to over-coating with anything. (Warm water and a nylon scrub brush).

And overcoat the epoxy you must, as epoxy has a very short life when exposed to sunlight (UV) *unless* it is over-coated.

If using varnish, use a name-brand "marine" varnish with UV inhibitors over the epoxy.


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