Re: [Paddlewise] Epoxies and Polyurethanes

From: Dave Kruger <kdruger_at_pacifier.com>
Date: Tue, 15 Jul 2008 19:50:25 -0700
Craig Jungers wrote:
> Since Paddlewise includes boat people from many varieties of boats, I
> thought I'd show you all a site I stumbled across this evening. The transom
> in my 34 year old Carver, Ad Hoc, has some dry rot in the core down at the
> bottom and I've been kinda looking around for some epoxy resin I could just
> inject through holes into the core to firm it up. I stumbled over this web
> page: http://www.rotdoctor.com/glass/GLrotrepair.html and thought I'd pass
> it along. They produce an epoxy that is sprayable!!! You can literally spray
> it into a small hole where its viscosity is such that it will then flow down
> into the substrate and invade the dry-rotted wood. When it cures then it's
> hard. It helps to use compressed air or something to dry out the wood.
> 
> This outfit also makes some polyurethane varnishes that look promising for
> kayak builders as well as other boaters.

I like System Three for stuff like this, but the Rot Doctor guy has done a 
fine job of merchandising his materials.  Wooden boat geeks quarrel about 
the efficacy of so-called "penetrating" epoxy formulations, with some 
claiming that the compartmented cellular structure of wood inhibits 
penetration much beyond a millimeter or so.  Such naysayers claim a repair 
made the Rot Doctor way looks good from the outside but remains infirm 
within.  These doom and gloomers assert that a hog it all out and bring in 
good wood to mate to whatever good wood remains is the only sure way to 
firm up dry rotted areas.

I don't know, myself, but I'd think some electron micrographs of 
cross-sections would be definitive.  Does the Rot Doctor have babies like that?

BTW, System Three has marketed water-based two-part polyurethane coatings 
(clear and in a variety of colors as well) for some 15-plus years.  that's 
what my mothership has on it, and I am stone-cold blown away at how durable 
the two-part formulations are:  an order of magnitude better than the 
one-part hardware store materials.  The West Coast Paddler crowd also has 
used this stuff, in clear, with excellent results, on kayaks.  Beats trad 
varnishes all hollow for durability.

No affiliation with System Three, just a satisfied customer.

Oh, yeah, they are also in the Seattle metro area.

-- 
Dave Kruger
Astoria, OR
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Received on Tue Jul 15 2008 - 19:51:35 PDT

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