CPES- (clear penetrating epoxy sealant)- uses, and how to make your own…

[DanishBagger]

Thanks Michael,

I _am_ new to epoxies. This project of mine is my first.

Nice site - I am reading through it right now.



Andre

[GrouchyOldCoot]

Originally Posted by BOATMIK

Howdy 'Bagger,

There I have put together some of the information I have written over the years on
http://members.ozemail.com.au/~store.../faqindex.html

If you are new to epoxies there might be some helpful stuff there that will save money and time.

Best Regards
Michael

Michael,

Dude where have you been? I have been looking for an intelligent person with a logical mind, such as yourself, on any of the internet boat forums since I joined. Finally a ray of light!

Now I realize the info comes from WEST and they have a vested interest in selling their epoxy BUT damn it makes perfect sense.

How can CPES be doing anything if allows water penetration? Its just lightly epoxy coating some percentage of the individual wood fibers (and not 100%)

Now I also understand that full epoxy coating of wood may trap moisture already inside the board and thus cause rot from within and yes if the epoxy coating is penetrated (crack, gouge, etc) the same could happen, but if CPES is letting in that much water, it really is not doing much. I have not read the info on your site yet, but I am headed off in that direction!

There has to be something in-between CPES saturation and total epoxy encapsulation of wood? (Just like there must be something better suited to bottom bedding than 3M 5200 – which is a whole other debate!)

[BOATMIK]

Originally Posted by GrouchyOldCoot

There has to be something in-between CPES saturation and total epoxy encapsulation of wood? (Just like there must be something better suited to bottom bedding than 3M 5200 – which is a whole other debate!)

Howdy Grouchy Coot,

If CPES allows the water content of the timber to go up to 40%.

And good quality epoxy systems allow the water content to go up to 8 to 10%

Then you are after a material that allows the water in the timber to reach 20%

Given that rot can start to be a problem over the low teens...

I wouldn't recommend your desired approach :-)

The above is the downside of a logical mind!

The other way to deal with the rot problem is the way the old time designers did it. Take huge pains over ventilation and drainage and things like protecting end grain. Epoxy coating allows any old chump to build a long lasting virtually rot proof boat.

I have spent much of my life maintaining other people's boats - and it is the last thing I want to do with my own. So I epoxy coat and it cuts the maintenance by a very large amount. With the price of paint and varnish these days (the marine ones are more expensive per litre than the epoxy - it is probably true of gallons too) by the time the boat is two or three years old I am starting to pull ahead of the game on financial grounds - and so far ahead on labour that there is no comparison.

Most of this is because the epoxy simply stops the moisture from getting in so the wood doesn't "move" - so joins, plugged screwholes and the like don't crack the paint - which is when the deterioration starts. Actually I prefer to use no nails or screws at all for just this reason.

Best Wishes to All
Michael Storer

[GrouchyOldCoot]

Thanks for the valuable experience.

[Aquamagi]

Paul Oman who posts on "epoxyproducts.com" says that xylene is a good thinner to make the epoxy penetrate. I would really like to get a clear statement on this. Does anyone know.

Hans A.

[Ramona]

I simply use methylated spirits to thin. Up to about 40%. Also use metho to clean brushes.

[PAR]

Aquamagi and Ramona, there's no debate here and this is a well discussed, tested and debated subject on a 5 year old thread.

There is absolutely no reason to thin epoxy with any solvent. If you're cutting epoxy 40% they you are so far off base that you really shouldn't be asking people to pay you for your efforts.

The bottom line is two fold; first is when you dilute epoxy with a solvent, like denatured alcohol (methylated spirits), you dramatically reduce every aspect of it's physical properties. A 15% dilution with denatured alcohol, will reduce epoxies compressive strength by about 40% and it's tensile and peel strength by 50%, plus it's ability to waterproof (the second point) goes right out the window. You might as well use straight alkyd varnish, which would have a better moisture resistance then epoxy thinned at 40%. At 40% you have bubble gum that doesn't resist moisture and has no meaningful strength.

In short, thinning, even just a little ruins epoxies ability to do much of anything. The truth about the issue, which has been born out in many tests, is the amount of "penetration" has absolutely no bearing on a coatings ability to waterproof! What all the tests have proven is, it's the quality of the coating, not the amount it penetrated the substrate that matters.

Lastly, unless you have a chemical understanding of what you're doing to a molecule when you screw around with it's formulation, you're just guessing. Clearly anyone using a reactive dilutant like denatured alcohol or xylene hasn't the foggiest idea what they're doing. There are a few ways to effectively reduce the viscosity of epoxy, for substrate penetration, wetout or what ever, but solvents aren't the way folks. The most commonly employed technique is called the hot on hot method, but you can also use a non-reactive modifier in the formulation if desired, though again, you have to have a clue about the molecule you're screwing with.

I hate to be so harsh, but I just can't believe people are still doing this. Epoxy is nothing like polyester or vinylester resin systems. These resins you can "play with" using solvents and all sorts of stuff, but epoxy is a wholly different animal and shouldn't be treated like the poly's.

Thanks Par.....again! I just don't understand why people continually want to take an incredibly good product and render it useless.
DON'T THIN EPOXY!!!!!

[Stumble]

I think people want to try and thin epoxy for a couple of pretty reasonable intentions, but without really understanding what it is.

First they look at the cost of decent epoxys, then at the way encapsulating is applied, and think, well this is like painting, so why shouldn't I be able to thin it like paint?

Of course the reason is that EPOXY IS NOT PAINT. It is a highly engineered product that requires precision in working with, and very tight controls to maintain its properties. Plus the fact that the 'penetrating epoxy' market has somehow fooled people into believing that the thinner the epoxy is the better it enter the wood. While it would be nice to get epoxy deeper, the fact remains that the viscosity of the epoxy has almost no effect on how deepely into wood it penetrates.

[PAR]

the fact remains that the viscosity of the epoxy has almost no effect on how deepely into wood it penetrates.

This isn't correct. The lower the viscosity, the deeper the penetration into a porous substrate (like wood). Temperature and non-reactive modifiers are the usual methods to reduce viscosity. Some epoxy formulations have less viscosity (the non-reactive modifiers thingie), such as Raka. Others can be heated quite a bit and still offer reasonable working times, such as West System extra slow 209, which can be easily taken to 100 degrees and you still have 30 minutes working time (45 minutes at 95 degrees). I have a proprietary formulation that's even better and can tolerate 110 degrees for 30 minutes (45 minutes at 100 and about an hour at 95). At these temperatures the epoxy is thinner then water and sucks into wood like a sponge. If the wood is hot (and cooling) when you apply the goo, it penetrates even further. This is the hot on hot method.

Agreed Stumble, the penetrating epoxy market has been whipped up by good advertising hype. I know people who swear by these products, but then again they don't get to repair and/or disassemble this things 5 years later to find the net result of these snake oil sales. For the most part repairer/restorers have realized what's going on and have backed off using these products, if not entirely, quite substantially. I very rarely find a need for thinned epoxy, though every once and a while I have a use for it. I made a reusable gasket out of thinned epoxy, the last time I made some up. I know the chemistry very well and have my own recipe, that doesn't do nearly as much damage to the physical properties, as most of the major formulations do (Smith's is a 37% cut, for example).

[ondarvr]

Originally Posted by PAR

I hate to be so harsh, but I just can't believe people are still doing this. Epoxy is nothing like polyester or vinylester resin systems. These resins you can "play with" using solvents and all sorts of stuff, but epoxy is a wholly different animal and shouldn't be treated like the poly's.

Thinning polyester and VE does about the same thing as in epoxy, you end up reducing just about every physical property. They become less water, UV and crack resistant in the best cases, some solvents will inhibit the cure dramatically and leave you with junk. The % range of monomer for best physical properties can be very narrow in some formulas and it's not wide in any of them.