Epoxy Before Varnish

[unbusted67]

Has anyone had any experience applying epoxy to wood before varnishing? I once applied West Systems two part epoxy to a pair of old oars that I had as an experiment and within a month or two the epoxy was badly discolored and cracked and it hadn't been outside. What are some methods and products people have used to reach a favorable outcome?

[delmarrey]

West Systems has a clear cure hardener #207 for finish work. If regular epoxy is left out in the sun it will yellow, even just over time it will yellow.

http://www.westsystem.com/ss/assets/...-Guillemot.pdf

[Wotname]

Use an epoxy with a UV stabilized hardener (it is the hardener component that breaks down with UV); there are some around but I am not familiar with USA available epoxies. Then overcoat with a several coats of exterior two pack varnish.

I did my tiller this way 2 years ago (well I used 7 coats of the 2 pack varnish over 4 coats of epoxy) and so far so good but I will probably give it a light sand and a couple of coats of 2 pack varnish next year .

[imagine2frolic]

I did some wood with just 207 & resin. It took nearly 2 years before it peeled, but only in the last couple of months did the color change. This was on the exterior. I did some panels on the interior with varnish & 207, and it almost looks like mirrors. That was several years ago, and it looks like the day I put them back in place.......i2f

[Lodesman]

I did my well-weathered teak tiller with ordinary West 105/206, sanded it smooth and covered with Interlux Goldspar - looks awesome and has held up for two years now. I gave it another quick sanding and recoat at the end of last season, but that was to fix abuse rather than weathering.

[unbusted67]

How do you apply it? That stuff is pretty gummy to begin with. Can you use 207 as a regular hardener for other projects?

[mikereed100]

What kind of wood are you finishing? I use an undercoat of epoxy as a sealer on open grained woods like oak, but on close grained woods like teak and mahogany I don't see any advantage as you will still have to varnish for UV protection. If the epoxy is too thick the best way to "thin" it is with heat. Leave it in the sun or pop it in the microwave for a few seconds.

Mike

[S&S]

I've used MAS clear for this. Works well under varnish. Whichever you use, you need to get the non-blushing hardener.

[cabo_sailor]

I know of one boat that used West System followed by varnish with stunning results. The lady doing it was obsessive about perfection. I've had less success when trying it. The epoxy with 207 hardner went on fine and looked super BUT before hardening the epoxy gets runny. I really hate stripping hand rails with all the nooks and crannies, it takes forever to do a good job. You can imagine my language when after applying the epoxy, admiring the look and returning to find all these little stalactites of epoxy hanging down from the underside of the rails.

Since then, even here in southwest Florida, I find about 8 coats of good UV resistant varnish will look almost as good, if not better, and it lasts about a year before needing another couple of coats.

Rich

[FloridaWriter]

Epoxy works very well under varnish to seal and protect the wood and provide a hard substrate for a protective clear coat, like varnish. I am encapsulating all of my bright work in West epoxy and then using System Three LPU clear gloss or mat over the top. The combination works very well but you must protect the epoxy from UV with a clear coating that has UV filters in it. I build up a surface of epoxy of 3 or 4 coats first, and wet sand progressively up to 400 grit. Then 3 or more coats of the clear. It comes out just gorgeous. If the clear protective coat needs to be sanded, the multiply coats of epoxy keep you from sanding thru into the wood.

I highly recommend West System epoxy, it flows very nicely and makes a flawless surface, but any marine epoxy would work for you.

Good luck,

[Mark Zarley]

Here is a little trick . To seal wood with epoxy and get penetration , thin with laquer thinner to the consistancy of water. Brush it on , I usually do 2 coats applying 2nd as soon as 1st gets tacky. No runs,no bubbles. For a uniform thin coat of thick epoxy, try one of those yellow spreaders, a brush does not apply it uniform enough.

[Cheechako]

I have seen many attempts become a nightmare... just as you describe. Evidently, if it's working for some there must be a real trick to it. Or maybe you just have to make sure you never wait too long to keep the varnish up.... which would work without the epoxy....

[mikereed100]

Originally Posted by Mark Zarley

Here is a little trick . To seal wood with epoxy and get penetration , thin with laquer thinner to the consistancy of water. Brush it on , I usually do 2 coats applying 2nd as soon as 1st gets tacky. No runs,no bubbles. For a uniform thin coat of thick epoxy, try one of those yellow spreaders, a brush does not apply it uniform enough.

I would be wary of using solvents to thin epoxy as they can alter the physical properties (ie: water resistance, color, shrinkage etc.).
Thinning West System Epoxy
You do want a thin mixture on porous woods, however, to avoid bubbling as the wood off-gasses. Heat preserves the physical properties of the epoxy while decreasing viscosity. But really, on teak or mahogany why bother with epoxy?

Mike

[Oceansandmts]

For varnish, varnish over epoxy, etc, etc, you need to have UV inhibitors in the top coats, which would normally be varnish. The UV inhibitors are eventually destroyed by the UV light, which is why you need to continue to apply coats of fresh varnish which contains lots of UV inhibitors. Epoxy by itself will be destroyed by the sun.

The issue of bubbles appearing in epoxy or varnish on porous woods as the coating sets is easily solved by making sure the temperature of the surface is dropping after it is coated, the coating will be sucked into the wood. If the temp is rising, the air in the wood will expand and cause bubbles.

[delmarrey]

Originally Posted by Oceansandmts

For varnish, varnish over epoxy, etc, etc, you need to have UV inhibitors in the top coats, which would normally be varnish. The UV inhibitors are eventually destroyed by the UV light, which is why you need to continue to apply coats of fresh varnish which contains lots of UV inhibitors. Epoxy by itself will be destroyed by the sun.

The issue of bubbles appearing in epoxy or varnish on porous woods as the coating sets is easily solved by making sure the temperature of the surface is dropping after it is coated, the coating will be sucked into the wood. If the temp is rising, the air in the wood will expand and cause bubbles.

And this is one reason teak has trouble holding vanish/lacquers. Teak is normally an oily wood. If it's coated with varnish or even paint and it's exposed to the sun on hot days the oils try to bleed out which cause blisters under the coating and eventually will crack or delaminate. There are some other Brazilian hardwoods that coatings will not even stick to but their not used on boats.

I found if you thin out epoxy with MEK to a runny state it will soak into the wood deep and after it cures makes a good base for more solid layers.