epoxy coating a wooden boat

LOL, well maybe you didnt know what you were trying to tell me, but you told me what I was looking for.

I thought the CPES would go deeper into the wood than Epoxy.
But the Epoxy would bond very well to the CPES.
So using the two products, should give a good grip on the wood.

Maybe good enough to keep the UV from destroying what grip the CPES had on the wood.

Your explanation was the normal Epoxy has a good enough grip, plus the water proofing as well.

I think I read somwhere that UV inhibitors can only keep the UV from going much farther than 3/8ths of an inch.

No paint is that thick, so it didnt seem worth while to add the expense of a UV inhibitor.

 

thudpucker,

I think maybe you have misunderstood UV protective coatings, the paint does not need to be that thick to work, it is a reflective property of protection for the substrates, and is basically essential to use some form of UV protection over epoxy base work, the epoxy cannot protect itself.

 

Bingo Lubber.

CPES is epoxy. In fact it's an acronym for Clear Penetrating Epoxy Solution. The Smith Brothers product is about 67% epoxy, the rest is solvents (a bunch of them). Other penetrating epoxies are similar in formulation.

I have never seen something that regular epoxy couldn't bond to, but a penetrating epoxy could or could much better then regular goo.

UV can penetrate quite deeply, but this is on unprotected surfaces. Anyone who's sanded a well weathered teak deck can attest to how deep the damage goes, before you're into pretty stuff again.

 

Yup,
It seems like all my life I never wound up with any wood boat that wasnt done for already.
I've been pretty dissapointed when I had to make a whole new Cabin or a fore deck.
The worst was down in the bilges or the insides of the chine.
I had a 33' Chris Craft that was so badly rotted, and nail sick, I just gave up and burned it.

The one time I had some rot in the inside chine support, I used CPES and it did follow the rot and made the board pretty stable.
A long time later, I took that Chine out (booger of a job) and cut into it just to see how the CPES did. It was all through the Chine board. The Rotted stuff was pretty solid, as if a wad of dody wood was glued together.

Up on the Deck, the surface wood was pithy. I took that off and put on new. I used CPES first, then Epoxy paint. I dont know the end of that story. The boats long gone now.

I do like seeing the lectrues. It's amazing what I did when I didnt know what I was doing!

Still, if I ever make this little Jon boat I'm thinking of, I dont know for certain how I'll make the seams/joints.
On the plywood surfaces, I think I'll just paint it with Epoxy paint. Or do you put a sealer on it first?

 

Howdy,

Interesting discussion. Like PAR I did think that the penetrating epoxies are the bees knees.

However, it is not really logical.

If thinning the epoxy made it bond better then all the manufacturers would be saying to thin the epoxy before gluing, or to put a thinned coat on first.

They all recommend firmly against it. So if gluing and you don't need to add solvent, why is it necessary for coating?

I think it is a hangover from when we used to use polyester resins for sheathing. Polyester doesn't bond to wood particularly well so getting to to "soak" was an attempt to get it to stick more.

Also you can look at what WEST have done with their branding. They have done more research by anyone by a long way ... it used to stand for
WOOD
EPOXY
SATURATION
TECHNIQUE

But after a lot of building one realises that epoxy doesn't and doesn't need to soak in very well at all. So now it stands for
WOOD
EPOXY
STABILISATION
TECHNIQUE

(You can probably tell I am from Australia by the S rather than a Z!)

I do know some trad boatbuilders use CPES while they are building to stabilise the wood a bit, but their reason is ... they know they can rely on water still getting into the planks to swell them and make the boat watertight.

Finally WEST published a little graph ... um ...
here



Penetrating epoxies make no difference.

Best wishes
Michael Storer

 

Just found the mother lode.

http://www.seqair.com/skunkworks/Glues/WestSystem/Thinning/Thinning.html

 

The use of penetrating epoxies or other products to cure rot is mainly a cosmetic solution. What I have usually seen is a clump of hard epoxy/rotted wood composite poorly adhered to what's left of the wood. On of the main problems with rotted areas is the high water content.

 

Right GONZO. That's exatly what I found when I cut the old Chine wood up.
Proving the CPES went in the Rot, followed it to its end, glued all the rotted pith to the good wood, and restored the strength of the wood.

Shipping the CPES was the bad guy in the mix. If you can buy all the epoxy you need at the local store, why buy CPES at a shipping cost almost equal to the purchase cos.

After all this discussion I'm still confused on what to do with my Jon boat as far as painting goes.

 

I and a few other odd balls (and called worse by those who claim they knew what they were talking about) have been pissing on the penetrating epoxy parade for years, particularly those that think they can just dump some thinner in to laminating resin and "go for it".

As far as painting your boat. Prep the surface. If this includes epoxy great, but skip the bother of the penetrating goo, smooth, prime and apply top coats of choice. Epoxy is a great sealer (the best). Don't confuse epoxy paint with lamination epoxy. They're not very similar in physical properties. Paint is paint and resin is resin, they don't interchange. If the "epoxy" paint is only one part (no separate hardener) then it's not really epoxy, but gussied up polyurethane.

 

Yessireebob. CPES and home-thinning epoxy is a dead subject.

"Smooth, Prime and apply top coats!"
I think I understand what your saying now.
Sand and fill, then use a primer. Is there such a thing as "Epoxy Primer?" Would that be the best to use?

So if I use Epoxy primer, then it follows that I should use Epoxy paint.
Is that correct or just another way of doing it.

What if I used plain old Oil based paint? "...and they dont mix!" is the answer to that one eh?

 

Thought i would throw my two penworth in! A few months ago i was at the Royal gunpowder mills at Waltham Abbey, in the museum is a powder barge, built in the 1850's of oak she had been sunk in one of the canals for many years. Of course once "salvaged" she practically disintegrated as the wood dried out & rotted rapidly. She has been treated extensively with a proprietary epoxy wood hardener, with some degree of success. Bear in mind that she lives on a concrete floor in a museum & will never float again, though now stabilised she has no more real structural strength than a loaf of bread would if you poured epoxy onto it.
Thats the thing epoxy is seen as a panacea for an old boats ills but in reality it often ends up as the kiss of death as it often makes a decent repair impossible.
It has its place but i would rather not use it!
Another case was a cold molded whitehall i built some years ago I did her brightwork in epoxy & linear polurethane varnish. It chipped as it was so hard and the water got under it & it flaked in places. After a few years i stripped the whole boat which was an absolute b'stard and refinished in oil based epifanes varnish. Paradoxically this lasted way better.

 

In years past I've read a bunch about wood.
It's my impression that what ever you put on Wood, it's only gonna have a grip on the outside .010 to .030 thouseant's of an inch.

Wood is mady up of three parts basically.

The UV rays seperate these parts and kill the one part. (Lignons if I remember correctly) which lets a lot of moisture reside in the wood right in the Wood/Preservative junction.

UV invasion is really the thing to beat.

Then you have the Chemicals of the Covering to deal with.

If you cannot beat the UV problem, it just dont matter a helluva lot, what you coat the wood with! It's gonna come loose. Even if the covering all sticks together and comes loose in big bunches.

Somehow I sorta got away from wood boats about the time all the info on the subject of Coverings and UV etc came along. I stopped reading all that stuff when I got a Glass boat.

Now I'm about to build this little Jon and the more I read, the more I'm confused. Mybe its my 'understander' that's the problem eh?

 

I don't know if mickjur is still here....this thread has taken on a life of its own!

Just a comment from an amateur if he is still here.

I think PAR is correct in his thinking about the penetrating epoxys.

I'm still restoring my 1973 Silverton (fiberglass hull, wood decks and cabin).

I've used System Three Clear Coat (which is marketed as a "penetrating" resin with "no volitile solvents"). It's somewhat thinner than regular System Three resin, but it doesn't smell of solvents.

I've found that coating new Douglas Fir ply with a thin coat of this product gives me a better base on which to apply fiberglass cloth. I've noticed that regular System Three "soaks in" to the ply in some spots, but not so much in others. I'm using 4 oz fiberglass cloth on the decks (Some might say this is too thin, but I'm only walking on the deck) finished with Interlux Perfection. Once the clear coat has set up, I can apply the cloth and the generic System Three Resin to a surface that evenly accepts the cloth and resin.

Thats the only place I use the Clear Coat.

Now the pros have likely developed better techniques to get a good base (perhaps using heat to reduce viscosity - which would get you the same result), but for me this approach has worked well. I also don't know how System Three Clear Coat compares with CPES as I've no experience with that product.

Regards,

MIA (still at it!)

 

LOL, Missinginaction is how I refer to my Congressman Robert Aderholt (R) of Alabama.

I always believed the Primer/CPES/Thinned Epoxy etc was to sink in and provide a good deep grip for the top coats.

Its just too much for me to read about so I rely on the guys (Par) who can back up what they say with logic.
So I'm gonna prime and paint with Epoxy. If my boat sinks, you'll be able to hear me yelling at Par as I go down.

 

If your boat sinks Thud, I suspect it have more to do with the amount of beer you've guzzled or the sharpness of the rocks you just run up on, then the quality of the coatings on your Jon boat. There was a guy in the news this weekend, his 24' center console was about 25' up into and on top of a rock jetty. The only camera shot of this fellow was him telling a county officer (who was about to take him to jail) that he didn't understand what happened, because the jetty wasn't there before, when he started out fishing that day. Apparently, he has little experience with tides and beer induced chart reading. Personally, I can read a tide chart quite well in this state, but this is my experience and fine seamanship showing.

The bottom line on this debate is simple. CPES and other penetrating products attempted to offer a product on false pretenses, suggesting that because it penetrated well, it would be a good thing. Well, the jury and separate testing has come in and their marketing ploy hasn't lived up to the advertising hype. Amount of penetration has little to do with (my other half would argue) coating performance. The ability for a coating to grip and more importantly, resist moisture vapor penetration are the keys to performance, not if one product soaks in better.