Boat epoxy vs 75%/ 25% vs exterior paint

[Ron Dickey]

On the Box Kite had it for 7 years and no sign of leaks I painted it with primer and several coats of exterior House paint.
I was told by a friend that I should use Boat epoxy (I live where boats are, but was told I can find it on the net [I do not shop the net] ) it will seal the pores and make it in to a solid plastic.
I researched it on the forum and found that may people use a mix of "75% Mineral Spirits - 25% Cheap Polyurethane varnish" which sound less expansive and will still have exterior house paint on top of that anyway.
I also have a friend who uses fiberglass, just to add one more to the mix .
Those of you who live in the east or north where it snows, rains, or in the mountains where it gets really cold will see the results faster.

Question 2 this is damp season how long will it take for epoxy or mix to dry?

I was about to put the sides up on my trailer but this stopped me and so I worked on other parts of my trailer until I could resolve this.

[Dale M.]

Epoxies are two part mix and they catalyze and harden in short time frames if mixed properly.... Temperature has a lot to do with cure time.... The warmer the better for epoxy cure....

The 75/25 mix as you state it sound like way to much mineral spirits and way to little polyurethane.... I rather think its 75% poly and 25% mineral spirits mix the is more desirable......

Dale

[tony.latham]

On the Box Kite had it for 7 years and no sign of leaks I painted it with primer and several coats of exterior House paint.
I was told by a friend that I should use Boat epoxy (I live where boats are, but was told I can find it on the net [I do not shop the net] Two-bits says you can find it cheaper on the net –Raka– than you can in a store.. Two-bits. ) it will seal the pores and make it in to a solid plastic. It'll seal it, but doesn't turn it into solid plastic. It will soak in depending on the wood and thickness of the epoxy.

Epoxy is hands down the answer to water proofing wood. (But you still need to UV proof it.) I don't believe there is any "boat epoxy." Epoxy resin is frequently used in boats for the obvious reason. I like the Raka brand epoxy. It's cheaper than the West System.

I researched it on the forum and found that may people use a mix of "75% Mineral Spirits - 25% Cheap Polyurethane varnish" which sound less expansive and will still have exterior house paint on top of that anyway.

I think the other poster is right. You've got the ratios flipped. I also think you never know what you are getting when you buy "mineral spirits," it's a generic chemical name. Look up the MDS sometime.

I also have a friend who uses fiberglass, just to add one more to the mix .

Fiberglass cloth is applied with either epoxy or polyester resin. Epoxy is much better than polyester but more expensive.
Those of you who live in the east or north where it snows, rains, or in the mountains where it gets really cold will see the results faster.

Question 2 this is damp season how long will it take for epoxy or mix to dry?

It has nothing to do with moisture. Epoxy doesn't dry, it cures through a chemical reaction. The time it takes varies on temperature and the type of epoxy (fast or slow) you are using.

I was about to put the sides up on my trailer but this stopped me and so I worked on other parts of my trailer until I could resolve this.

I've got a build going right now and it'll be epoxied after the roof is on and before the aluminum skin goes on...

Tony

[MtnDon]

First, let me state I am not an expert on this, not a chemist, not an engineer, etc...

I have trouble understanding the thought behind dilution. The substance added as a dilutant evaporates relatively quickly I would think. When it evaporates it leaves behind "holes" or bubbles where the thinner used to be. Seems to me this is similar to using too much water in mixing concrete. When the water evaporates it leaves a void and the concrete is weaker than it would be with a proper amount of water.

If the epoxy hardens before all the thinner has evaporated would we not have bubbles or droplets of thinner encapsulated by hard epoxy? Or would the epoxy be as hard it should be? ???

Epoxy does make a great sealer / primer for the final coats of paint.



Is there something I am missing about this dilution process that many folks are enamored with?

[tony.latham]

First, let me state I am not an expert on this, not a chemist, not an engineer, etc...

I have trouble understanding the thought behind dilution. The substance added as a dilutant evaporates relatively quickly I would think. When it evaporates it leaves behind "holes" or bubbles where the thinner used to be. Seems to me this is similar to using too much water in mixing concrete. When the water evaporates it leaves a void and the concrete is weaker than it would be with a proper amount of water.

If the epoxy hardens before all the thinner has evaporated would we not have bubbles or droplets of thinner encapsulated by hard epoxy? Or would the epoxy be as hard it should be? ???

Epoxy does make a great sealer / primer for the final coats of paint.



Is there something I am missing about this dilution process that many folks are enamored with?

Don: He says he hasn't put up the walls, so he's talking about a new build, not coating his old painted build with epoxy. (I think). There has not been any discussion on thinning epoxy in this thread, just thinned polyurethane –I'm assuming to get it to soak deeper into the wood. Raka suggests warming their epoxies over thinning (with alcohol), so you're probably right on thinned epoxy being weaker or more porous.

TL

[MtnDon]

Thinning polyurethane would seem to leave the same voids when the thinning agent evaporates. At least it does to me.

[Ron Dickey]

Epoxies are two part mix and they catalyze and harden in short time frames if mixed properly.... Temperature has a lot to do with cure time.... The warmer the better for epoxy cure....

The 75/25 mix as you state it sound like way to much mineral spirits and way to little polyurethane.... I rather think its 75% poly and 25% mineral spirits mix the is more desirable......

Dale

copy this line
75% Mineral Spirits - 25% Cheap Polyurethane varnish
into the search site above.
Apparently it allows it to soak in deeper, they put on several coats.

Dale thank you for your input

Doug H.offers this sticky above on epoxy
viewtopic.php?f=21&t=18512

and for the PAINT answer I got this on a different thread
have scratched my head over some sort of waterproofing and I think paint will do just fine. Thin coat of primer, then a thick coat of primer, followed by a thin top coat and thicker top coat.
A tip given to me by an aircraft paint guru for painting wood, let the primer completely dry before applying another coat but don't wait more than 12 hours. He explained how the primer soaks in and seals the wood for the next coat. If you wait too long after, you have to reactivate the primer by scuff sanding and wiping down. Also the type of roller you use has a major effect on the outcome, short mat for smooth coats, long mat for texture.

Ron

[Campin' Texan]

I coated all of my exterior wood with System Three epoxy. Then I painted my tear with System Three polyurethane boat hull paint. It's UV resistant and chip resistant. I got to pick what color I wanted my tear. It's not cheap at $150 a gallon, but it's cheaper than aluminum. And 1 gallon covered 5 coats on my 5x10 benroy. I've been extremely happy with it.

http://www.systemthree.com/store/pc/WR-LPU-Topcoat-c29.htm?pageStyle=m&ProdSort=19&page=3&idCategory=29&viewAll=yes

[Ron Dickey]

That sounds grate But I tend not to order things on the net. Thanks you very much for your input others may go that way.

I am very picky about color and do not mind repainting.
http://www.homedepot.com/p/BEHR-Premium ... /204946230

This is the aprox. color I want the outside walls, it matches my house. The trolley top is power blue and the roof will be white. I may be sorry later but think I will not go in that direction.

I work at HD the walls of the boxkite were painted with HD glossy paint and the top with Ace Hardware glossy paint on the roof. Walls were primed several times.

I would love to have a car finish and your System 3 might take me there.
I have not looked in the yellow pages yet. There is a West marine in Santa Barbara, CA.
http://www.westmarine.com/
Ron

[48Rob]

Don,

Thinning varnish may or may not leave "voids" as the solvent evaporates, but most of the coatings I've ever applied have some form of solvent as the carrier, which is designed to evaporate leaving a thin film coating.

I've thinned the first coat of varnishes and oil based paint for years, based on old timers instruction, and the general thought that the thinner base coat will penetrate more deeply into the wood, whereas a thick undiluted coat will simply sit on top.
In my use, I have no concern about voids in the thinned initial coating(s) as I always apply several undiluted top coats after.

You got me curious, so I looked around and found this from Jamestown Distributors regarding Epifanes varnish;
http://www.jamestowndistributors.com/us ... ?docId=205

Why do varnish manufacturers recommend thinning?

Proper thinning of the varnish is very important. If you apply the first coat of varnish full strength, the entire varnish system will adhere to a coat that is sitting on top of the wood. Not good. Therefore, significant thinning (50% or 1/2 & 1/2) of the first coat is very important. A very thin "sealer" coat will give maximum penetration and good grip for the subsequent system. It is quite normal for a manufacturer to recommend a thinning of the first few coats progressively building to full strength.

Rob

[MtnDon]

Key word there seems to be "proper" (thinning). I'd do whatever the mfg recommends and nothing further. They know their product best. The mention of 75% thinner just seems plain wrong. Excessive thinning is also delivering a whole boatload of VOC's to the atmosphere which may not be a good thing. But that is another story.

As for what happens when the poly / varnish has been diluted a huge amount we would need a test, a study. I have looked but can not find it right now, but the USDA Forest Products people did a dilution study a number of years ago. If my memory is any good I think they found that excessive dilution does no good and might cause degradation of the varnish or whatever they were testing. But I can not find it.

And this may just be my preferences but I don't like clear (or amber) finishes on wood that will be outdoors as a rule. That's a personal thing that has come from seeing what the desert sun and dryness does to kill the finish. I prefer paint and primers, again according to the mfg.

[Esteban]

Ron,

raka.com/epoxy_kits
Raka's 1-1/2 gallon kit might be all you need for $98. Use a pre-paid credit card if you want to be really safe ordering over the internet.

I've bought from them several times in the past problem free.

I'm using Raka epoxy. Will soon need to order more. Come by sometime and I'll show you how it works. I now have a HF digital scale to measure the epoxy and hardener accurately which should eliminate mix ratio boo boos. Properly mixed epoxy cures and hardens within hours. It mostly depends on the temperature, warm temperatures speed up curing, and the type of hardener used (Raka has slow, medium, and fast hardener).

You can use almost any paint you want on top of epoxy.

[Ron Dickey]

Ron,

raka.com/epoxy_kits
Raka's 1-1/2 gallon kit might be all you need for $98. Use a pre-paid credit card if you want to be really safe ordering over the internet.

I've bought from them several times in the past problem free.

I'm using Raka epoxy. Will soon need to order more. Come by sometime and I'll show you how it works. I now have a HF digital scale to measure the epoxy and hardener accurately which should eliminate mix ratio boo boos. Properly mixed epoxy cures and hardens within hours. It mostly depends on the temperature, warm temperatures speed up curing, and the type of hardener used (Raka has slow, medium, and fast hardener).

You can use almost any paint you want on top of epoxy.

Thanks Steve,
I'll come by and see. I'll call first.
I have been wanting to get a PP Credit card, I hear you want one you can call the card company and make you name is attached to the card, or seller will think it is a fake. Like amer. exp.
I am on the verge of doing just paint.
Ron