...for the right application, and if used as intended.

It might be great stuff for a "natural" finish on a Greenland stick. Certainly sounds like good stuff to put on a Bird's mouth shaft to prevent cracking in the individual laminations.

Shawn

: Good questions. Before answering, let me ramble for a while. Full disclosure:
: I have no financial interest in CPES. I buy it from the same source and at
: the same price as anybody else. Never used it until last summer. Then I
: got a call about waterproofing an old log house. (The call came through
: Nick - thanks Nick, I owe you one! ) Now this place was built in 1903,
: and has seen 98 Seattle winters. You can imagine how punky, moldy and
: insect-infested these logs were, particularly on the south side. Several
: had been replaced 6 years ago because they just rotted away, but they were
: in danger of doing the same thing due to the same conditions. When logs
: dry out, they develop radial checks and cracks, and any that face upward
: become sources for water to penetrate into the heart of the log. Then it's
: time for the molds and insects to chow down.

: As a pretreatment for a comprehensive waterproofing regimen, I wanted to
: saturate the cracks with epoxy. If the moisture content of the wood stays
: below 20%, the molds stay dormant. And the insects haven't developed a
: taste for plastic. I tried several penetrating epoxies on mockups,
: including System 3 Clear Coat and CPES. CPES provided by far the best
: penetration, and I then used several gallons of it. There were places
: where CPES ran out the end grain of a log 10 feet away from where I was
: injecting it! After an overnight gullywasher, and before the rest of the
: waterproofing was done, I checked the substrate with a moisture meter, and
: found that all of the treated wood was under 7%, while untreated wood in
: adjacent areas was all over 18%. That right there tells me everything I
: need to know about the product.

: Now, about boats. There are no UV blockers in the product, so any epoxy on
: the surface suffers UV degradation over time. But the product penetrates
: full depth, and the wood itself protects all of the penetrated epoxy from
: UV exposure. There is almost no film built, a small fraction of one mil.
: (One mil is .001") Deep waterproofing in wood just doesn't get any
: better than CPES.

: There is another advantage to this product as well. All epoxies are made from
: phenol and acetone. Phenol can be derived either from coal tar or wood
: tar. Most (and cheapest) phenol comes from coal tar, and the resultant
: epoxy tends to be brittle. Those made from wood tar tend to be more
: flexible. CPES is in the latter group, according to the manufacturer, and
: that is a good thing for a waterproofing material. The strength of the
: wood is not compromised by introducing a brittle adhesive throughout the
: wood fiber matrix. So the boat or paddle can bend and flex without the
: high point loads and catastrophic failure that has been alluded to in
: previous posts.

: For paddle applications, there is another benefit. I know from rowing in
: college that a rough natural wood grip causes less blisters than one with
: any kind of finish on it. With CPES the protection is IN the wood, not ON
: it. A light sanding gives a velvet natural texture that is kind both to
: the eye and the hands. And it's permanent.

: There is a drawback, of course. A couple, really. At $32.02 per 2-pint kit,
: $44.95 for 2 quarts, or $144.76 for 2 gallons the stuff is pricey. And
: there are 18 volatile organic solvents in it, about 50% of total volume,
: so handling precautions, good ventilation and personal protective
: equipment are in order. The label says "This product is inherently
: unsafe. It cannot be made safe." With that said, given the small
: volumes and short durations inherent in boatbuilding, risks are minimal
: when good handling practices are used.

: For my money, penetrating epoxy doesn't get any better than CPES.