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Old 05-01-2010, 03:26 PM   #21
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RE: Epoxy Questions

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Marin wrote:I guess that's something you'll have to take up with the CPES folks, since the owner of Rot Doctor here in Seattle**has told me that they DON'T use MEK in their product which he says say is why the product he carries*works better as a penetrating epoxy sealer than simply mixing regular epoxy with MEK.
Marin, if you look at the MSDS sheet for CPES, you'll see that it contains Xylene, Tuolol, Isopropyl alcohol, 2-Butanone, 4-Methyl 2-Pentanone, etc.* These are not Tofu based ingredients, and when a chemist says 'organic' solvents he means something rather different from your local juice bar.* 2-Butanone is the chemical name for MEK, so Dr. Rot probably needs to take a chemistry class or read his own MSDS.* By the way, this is a great product, it is just a lot more expensive than regular epoxy thinned out, and to sell their product, Smith's tends to, shall we say, obfuscate what they are actually selling?* Otherwise, how could they convince you, as their web site says, that "This Stuff is True Magic!" so you'll pay through the nose for the product?

*
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Old 05-01-2010, 03:33 PM   #22
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Epoxy Questions

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RickB wrote:

Marin is right, CPES is not epoxy thinned with MEK. It is epoxy thinned with naptha, xylene, and toluene in decreasing proportions. About 70 percent of the stuff is solvent.

Look at the MSDS if you want to see what is in it.

*
From that MSDS for CPES, you see that 2-Butanone is one of the ingredients.* From Wikipedia:* Butanone, also known as methyl ethyl ketone or MEK, is an organic compound with the formula CH<sub>3</sub>C(O)CH<sub>2</sub>CH<sub>3</sub>.

They don't spell out MEK on an MSDS because the chemical name for it is 2-Butanone.
Incidentally, if you look at a can of MEK, you'll see that one of its listed primary uses is as a thinner for epoxies.





-- Edited by Delfin on Saturday 1st of May 2010 04:33:10 PM
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Old 05-01-2010, 05:29 PM   #23
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RE: Epoxy Questions

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Delfin wrote:
From that MSDS for CPES, you see that 2-Butanone is one of the ingredients.*
Good catch, thanks ... I didn't bother to look it up as beyond about the 3rd ingredient the percentages usually get pretty small. I'll know better next time.
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Old 05-02-2010, 11:38 AM   #24
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RE: Epoxy Questions

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RickB wrote:

Just like the mouse milk folks, these guys depend on establishing a cult following based on ignorance of the process and the blend of ingredients. The only way to get rid of rot is to replace the rotten wood. All you get with magic wood restoration products is a volume of plastic surrounded by rotten wood.


If you believe CPES (or thinned epoxy if that's what you prefer to use) will get rid of rot, you are absolutely correct, it won't and it's silly to think it will.* What CPES does extremely effectively is prevent the start of rot if wood is treated with it beforehand.* This is how its use is advocated by the shipwrights and restoration and maintenance experts on the Grand Banks forums.* If wood is rotted, no question, cutting out the rotten portions and replacing with new wood, or replacing the entire structure with new wood, are the only cures.

But if new wood-- or undamaged old wood that is being refinished-- is first saturated with CPES, this permanently seals the outer layer of wood cells against moisture intrusion and also helps maintain the integrity of whatever finish you put on top of it, paint, varnish, etc.* (You have to put something over CPES because it is not UV resistant).

Smiths/Rot Doctor do carry a product that can be used to replace rotted wood in small areas.* It's called "Fill It" (I think) and it's a putty-like two-part epoxy similar in concept to Bondo but made for a marine environment, which Bondo is not.* Where it's very useful is on window frames, for example, that might have a rotten section in part of a frame section.* The rotten wood is cut or carved away and replaced by Fill It which, once cured, can be sanded to blend with the rest of the frame.* This makes for a permanent repair which in many cases is far easier and less expensive than replacing the entire frame section.* But there's a point at which it becomes more effective to replace the whole section.

CPES is not a magic bullet but there are instances where it can "fix" a rot problem.** I have used it very effectively to solidify and protect the failing plywood underdecks of our three lazarette hatches which had sections of soft and crumbling wood where they simply never dried out.* After letting the hatches dry out thoroughly (which took the better part of a month inside our house) and sanding away the punky wood, repeated saturations with CPES turned the plywood hard as a rock and they have held up beautifully for the ten years since we did this.

*
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Old 05-02-2010, 10:00 PM   #25
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RE: Epoxy Questions

Marin, you identified one of the critical factors in successfully dealing with punky wood, and that is drying it out completely first.* Rot Dr. makes it sound like their product can be applied with some moisture in the wood, but that is not my experience.* If there is any, no epoxy, including theirs, will dry correctly.* The best method is as you describe - dry it out completely, remove the rot, soak the wood around the rot with epoxy, then fill or replace.* I soak all plywood edges with thinned epoxy before building anything that will be subjected to moisture to avoid this problem in the first place.* For very moist areas, like an ice box, I have painted a couple of coats of thinned epoxy on before laminating with epoxy glass.
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Old 05-03-2010, 11:44 AM   #26
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RE: Epoxy Questions

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Delfin wrote:

Rot Dr. makes it sound like their product can be applied with some moisture in the wood, but that is not my experience.
Yes, I know they imply or say that CPES can penetrate wood and "displace" moisture, but that claim is one I do not*practice.* CPES might*so this to a degree, but why compromise the project if you're going for a*permanent fix?*

To me, having the wood--- new, stripped old wood in good shape, or having rot problems--- completely dry is the correct way to start off with CPES.* And from our hatch project, it's amazing how long it can take water-soaked wood to completely dry out.* We set the hatches up vertically in one of our bathrooms during the winter so there was heat on in the house most of the day (we built a temporary plywood cover for the big open hole in the aft deck of the boat).* And it took weeks for those three hatches to dry out completely.* They literally dripped water from the lower edges for a good portion of that time.
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