Epoxy vs Varnish

[Plymouth Sailor]

Dear Sailors,

I recently built a bar using red oak as a top and finished it with a clear epoxy made specifically for table tops (the ones you see where the artisan uses coloring in the gaps of the wood like a river flowing). Has anyone used this product to finish wood on your boat? I would imagine it would look tremendous but wondering if, like varnish, it stands up to the weather.

Your wisdom appreciated!
Mark

 

[kbgunn]

Expoy is great for sealing wood! Cured epoxy will turn yellow with UV exposure so you would still need to protect it from UV. One approach would be to use epoxy for bottom coats and put a few coats of varnish over the epoxy to protect from UV.

Oily woods like teak will need to be wiped down with a solvent (acetone is good) to remove the surface oil before applying the epoxy.

This is an excellent resource for this approach:

 

[MikeHoncho]

Consider the work to remove it when it fails……they all fail at some point

 

[jssailem]

This is a pine stern seat. I sanded it and covered it with a coat of epoxy. Then since I planned to leave it exposed on the boat I gave it a coat of varnish. The problem with epoxy on pine exposed to the weather is expansion. It bubbles and cracks the epoxy. Then it flakes away. A good varnish will expand and contract with the changes in the atmosphere.

 

[Plymouth Sailor]

Consider the work to remove it when it fails……they all fail at some point

True, I did think of that, good point, however the previous owner of my boat used indoor finished plywood which is slightly delaminating. I need to purchase some Lloyds marine plywood but not on my list this year so I thought this would be a good temporary fix until I can replace, thanks!

 

[Plymouth Sailor]

Expoy is great for sealing wood! Cured epoxy will turn yellow with UV exposure so you would still need to protect it from UV. One approach would be to use epoxy for bottom coats and put a few coats of varnish over the epoxy to protect from UV.

Oily woods like teak will need to be wiped down with a solvent (acetone is good) to remove the surface oil before applying the epoxy.

This is an excellent resource for this approach:

Nice, thank you!

 

[Plymouth Sailor]

This is a pine stern seat. I sanded it and covered it with a coat of epoxy. Then since I planned to leave it exposed on the boat I gave it a coat of varnish. The problem with epoxy on pine exposed to the weather is expansion. It bubbles and cracks the epoxy. Then it flakes away. A good varnish will expand and contract with the changes in the atmosphere.

View attachment 224828

Thanks

 

[Plymouth Sailor]

Expoy is great for sealing wood! Cured epoxy will turn yellow with UV exposure so you would still need to protect it from UV. One approach would be to use epoxy for bottom coats and put a few coats of varnish over the epoxy to protect from UV.

Oily woods like teak will need to be wiped down with a solvent (acetone is good) to remove the surface oil before applying the epoxy.

This is an excellent resource for this approach:

Good video, I also use foam brushes and foam rollers, they work well.

 

[dlochner]

Epoxy is not UV stable. It must be coated with a UV protective coating, doesn't matter if it wood or any other substrate. If the coating fails, the epoxy will fail.

Epoxy becomes soft at about 150°F making it relatively easy to scrape off without damaging surrounding surfaces.

 

[Ralph Johnstone]

I think this is as close to an infinite life expectancy you're going to find :

The steps are about ten years old and still no need of re-varnishing. The underlying trick here is that I used a light glass cloth under the three coats of epoxy. The cloth is invisible as the epoxy and glass have the same refractive index. Lastly covered with three coats of spar varnish. Steps are not covered at any time.

This is an outside application :

This only has Silver Tip Clear finish, no glass cloth but five coats of epoxy. Again, about three coats of varnish for UV protection. These transom seats are covered when the boat is not in use but they get plenty of exposure in the summer.

Several secrets in applying epoxy that make all the difference between perfection and a dumpster fire, such as 100% encapsulation with epoxy.

 

[Hello Below]

I think this is as close to an infinite life expectancy you're going to find :

View attachment 224829

The steps are about ten years old and still no need of re-varnishing. The underlying trick here is that I used a light glass cloth under the three coats of epoxy. The cloth is invisible as the epoxy and glass have the same refractive index. Lastly covered with three coats of spar varnish. Steps are not covered at any time.

This is an outside application :

View attachment 224830

This only has Silver Tip Clear finish, no glass cloth but five coats of epoxy. Again, about three coats of varnish for UV protection. These transom seats are covered when the boat is not in use but they get plenty of exposure in the summer.

Several secrets in applying epoxy that make all the difference between perfection and a dumpster fire, such as 100% encapsulation with epoxy.

Very impressive Ralph . . . for a mainlander!
I assume you take the slates off the diva seats in order to 100% encapsulate them. How do you affix them to the starboard once you have completed your beautiful restoration?
A really, really nice job. By chance are you for hire?

 

[Ralph Johnstone]

By chance are you for hire?

Yes, but not for what you're expecting .

The slats are removed to seal them with 10% thinned epoxy on both the top and backside BUT to ensure they are 101% encapsulated when they are screwed back on to the starboard, the original screw holes in the teak slats are filled with Big Box GE Silicone Bathroom, and Kitchen, and aquarium, and Tub, and Everything Sealant because I believe silicone DOES have a place on boats contrary to what the purists say. (Phew !). The above mentioned silicone sealant, just by being there, is in itself sealed from the environment and resists any degradation.

The teak must be hermetically sealed against moisture intrusion. IF moisture does get into the wood through any tiny crack, the only way out is through that same tiny crack and that's just not going to happen once the moisture has dispersed through the extremely dry teak (another mandatory requirement). The resulting water vapour pressure is going to pressurize and break the bond between the wood and the first layer of epoxy. This is quite likely what happened in @jssailem 's stern seat :

Done correctly, the pine stern seat should last a long time. Even longer with any sort of protective cover.

 

[dlochner]

Yes, but not for what you're expecting .

The slats are removed to seal them with 10% thinned epoxy on both the top and backside BUT to ensure they are 101% encapsulated when they are screwed back on to the starboard, the original screw holes in the teak slats are filled with Big Box GE Silicone Bathroom, and Kitchen, and aquarium, and Tub, and Everything Sealant because I believe silicone DOES have a place on boats contrary to what the purists say. (Phew !). The above mentioned silicone sealant, just by being there, is in itself sealed from the environment and resists any degradation.

The teak must be hermetically sealed against moisture intrusion. IF moisture does get into the wood through any tiny crack, the only way out is through that same tiny crack and that's just not going to happen once the moisture has dispersed through the extremely dry teak (another mandatory requirement). The resulting water vapour pressure is going to pressurize and break the bond between the wood and the first layer of epoxy. This is quite likely what happened in @jssailem 's stern seat :

View attachment 224836

Done correctly, the pine stern seat should last a long time. Even longer with any sort of protective cover.

I'm beginning to think SBO needs to do something about Ralph. He keeps setting the bar too high for us mere mortals. I hear the boat lives in a barn and all the water backgrounds are photoshopped in.

While preparation and completely sealing the wood is of paramount importance, the species and cut are also important. Some wood is more prone to movement, i.e., swelling and warping than others, common pine would be high on the list of poor wood choices, it is soft and wide grain which will allow it to easily absorb moisture. Quarter sawn lumber of any kind is more stable than flat sawn wood. The grain is tighter and it is less likely to warp or cup.

Spar varnish can stretch a bit to help compensate for wood movement, however eventually the finish fatigues and begins to crack which allows moisture to enter the wood, which will eventually vaporize and put pressure on the finish causing it to bubble and crack. Ralph is right, the wood must be bone dry and tight grained. And it is best if it is a hard wood that does not easily absorb moisture.

One trick to get epoxy to saturate wood is to heat the wood before applying the epoxy. This will cause air and moisture in the wood to escape. After the epoxy is applied and the wood begins to cool, it contracts and sucks the epoxy deeper into the wood grain and cells. There is also less air and moisture in the wood to heat up and blister the finish.

 

[Ralph Johnstone]

​

I hear the boat lives in a barn and all the water backgrounds are photoshopped in.

ALRIGHT, alright, damn it, I admit it. The boat spends all its time leaned against a brick wall and painted sheets of ocean are sometimes inserted behind to show varying degrees of rough water ........

common pine would be high on the list of poor wood choices, it is soft and wide grain which will allow it to easily absorb moisture.

Bah, Humbug.

1. Dry the pine until it has very little water.
2. Paint the pine with epoxy thinned with 10% lacquer thinner.
3. While the first coat is still tacky, coat all areas of the wood with light glass cloth and then 100% epoxy.
4. Add four more coats of epoxy while each previous coat is still tacky.
5. Allow to set for a week and paint with 3-4 coats of spar varnish.

Check for the possibility of a blush but modern epoxies did away with that years ago.

No need to worry about moisture absorption as the wood is hermetically sealed with epoxy. No need to worry about vapour pressure as there is very little water content in the wood

Just simply no need to worry ....................

 

[MikeHoncho]

I think this is as close to an infinite life expectancy you're going to find :

View attachment 224829

The steps are about ten years old and still no need of re-varnishing. The underlying trick here is that I used a light glass cloth under the three coats of epoxy. The cloth is invisible as the epoxy and glass have the same refractive index. Lastly covered with three coats of spar varnish. Steps are not covered at any time.

This is an outside application :

View attachment 224830

This only has Silver Tip Clear finish, no glass cloth but five coats of epoxy. Again, about three coats of varnish for UV protection. These transom seats are covered when the boat is not in use but they get plenty of exposure in the summer.

Several secrets in applying epoxy that make all the difference between perfection and a dumpster fire, such as 100% encapsulation with epoxy.

beautiful but I would have killed myself 5 times over if I did that to my steps. Heck, I've slid down mine with no finish.....

 

[Ralph Johnstone]

beautiful but I would have killed myself 5 times over if I did that to my steps. Heck, I've slid down mine with no finish.....

It's all in the fine details :

The rough surface is caused by a crushed quartz anti-skid product being applied to the second coat of wet varnish and once dry, covered with a third and final coat of varnish. This was done as a 1" strip of anti-skid as I couldn't run the risk of covering up the fine teak finish. That would never do. Just ignore the broken ankles. "Walk it off. Walk it off ya sissy."

Also, the black strips in the teak steps are the product of a long wet winter. Just as a make-work addition, I dadoed out the 1/4" grooves and then poured in black tinted clear epoxy. DON'T ask me why I used black as I have no idea whatsoever. All I can figure is "like ya know, an acid flashback to the sixties man ?" Once I had finished the steps and before installing them on their SS tube frame, it dawned on me that the steps were supposed to match the flooring with a 1/4" strip of blonde holly, not black ebony.

Screwed them on to the SS tubing and on to the next project. Just sticking to my motto up on the wall of my workshop :
"Always aim for perfection and accept whatever $hit comes out of it. Amen."

 

[dLj]

I like the black...

dj

 

[JBP-PA]

Of course each project varies. If you can't do 100% encapsulation or if removing failed epoxy would be a problem, straight varnish is still a viable option for many projects.