Posted by Jim on October 19, 1998 at 07:40:35:
In Reply to: CAN EPOXY RESIN W/KEVLAR BE APPLIED TO RAW AIR DRIED HARDWOODS posted by IAN HAIG on October 14, 1998 at 20:51:45:
I'm surprised no one has responded to your query. I wish some of the experienced boatbuilders at Glen-L or elsewhere would help out us novices by sharing some of their knowledge. Since no one has responded in almost a week, I'll share my very meager knowledge. I am not very experienced, but I've been doing a lot of research into methods of preserving old and new wood. It's a deep subject, and there are a lot of good, and bad, answers out there.
A lot of people are into "encapsulating" wood in epoxy, to forever keep the water out and make the wood last almost forever. But a lot of people question the ability of even the best modern epoxies to perfectly exclude water. Epoxy is harder than wood and with or without fiberglass (or kevlar), is bound to develop microcracks which will let water in, but not out again. Even if there are no microcracks, there are still screw holes, and in the case of your new boat, thousands of interfaces between planks and frames which will work and crack the epoxy. The results are obvious.
What we need to do is PENETRATE the wood with something that will make it impervious to rot or, better still, to water. Wood preservative works well, but there's a question as to whether epoxy will adhere to treated wood. Thinned epoxy will penetrate, but the epoxy manufacturers warn against that practice.
A friend showed me an article in Classic Boating Magazine (March/April 97) called "Better Wearing Bottoms" by Don Danenberg. The author claims many years of experience in restoring old mahogany runabouts, and impressed me with his knowledge. He claims that epoxy penetrates only 0.01" into wood, and has no place in boat restoration. He uses a product called Smith's CPES (Clear Penetrating Expoxy Sealer) which penetrates deeply, and remains flexible.
I went to the Internet to try to find CPES and only found a character who calls himself the Rot Doctor, who markets the stuff. I haven't found a competitor yet. The Rot Doctor has a very interesting website at www.rotdoctor.com. Although he is selling a product, I get the impression he knows CPES well and really believes in it. I must confess that I haven't yet bought any, but I'm very interested, and I am NOT trying to advertise its source! I'd rather see some competition!
I very strongly recommend getting a copy of the article, and reading the website. I think there's a lot of good info there which you should consider. The article mentions serious damage that can be done to a wood boat with improper methods. Don't risk your investment.
Finally, if any experienced boat builders read this, PLEASE RESPOND! Do you have bad or good experiences with CPES? Have you heard of any pros and cons? Is encapsulation as bad as I've heard? How about on a new boat like Ian's? C'mon, guys, give us a hand here!! Let's put this forum to use and generate some discussion!