The Rot Doctor

Date: Tue, 01 Apr 2003
Subject: Suggestions for Sealing Canvas on a (formerly) Folding Kayak

Dr. Rot,
I could have used you (and the Internet) when I was maintaining a 1958 32' mahogany fishing boat and a 1929 30' Lawley sloop. Those days are long gone but I am trying to maintain a canvas over wood frame kayak. It used to fold, but I have no intention of doing so in the future. I would like to strengthen and seal the canvas hull (especially at the seams) while trying to keep the boat as light as possible.

My first concern is removing the existing "paint" which appears to be some sort of silver coating. I was thinking of using one of the PeelAway products to do this.

Probably your best choice. You will want to be as gentle as possible so as not to damage the canvas. After the paint removal, wipe the canvas down with lacquer thinner to clean.

I was originally thinking of then costing the canvas with a flexible epoxy such as Gluvit, SS Coating's Aquaflex 96, or a West product. Then I found your site. Reading through your literature, I wonder what I should follow a base coat of CPES with given that I'm applying over canvas: Your Lay-up and Laminating resin or ELASTUFF 120. Whichever I use, I was figuring on finishing with a coat of 2-part brushable polyurethane.

Can you give me any guidance?
Patrick W.


ELASTUFF would work, but it is rather heavy, and requires an additional topcoating to protect from UV light discoloration. I would suggest instead the CPES first and then within 2-12 hours (as soon as the CPES becomes tacky) a coating of our Elasta-Tuff™ 6000-AL-HS (which is a brushable polyurethane coating). Two coats of this would be required, and your 2-coat coverage would be 50 sq ft per gallon. Elasta-Tuff™ 6000-AL-HS is a waterproof, tough, totally UV resistant coating that remains flexible. It's final finish is a matte-gloss. It's easy to apply and can be retouched. It's a lot tougher than standard 2-part polyurethane coatings, and a much better option than solid epoxy coatings.

I would suggest coating the seams twice with the CPES, allowing at least one day to pass between coatings. The remainder of the canvas should do fine with a single coating, although multiple coatings would certainly do no harm. By applying the first coat of Elasta-Tuff™ 6000-AL-HS on the final coat of CPES while the CPES is still in its curing phase, the curing epoxy "locks-in" the first coat of the Elasta-Tuff™ 6000-AL-HS. Makes for a very durable bond. The second coat of Elasta-Tuff™ 6000-AL-HS should be applied within 12 hours of the first coat for the very best bonding. Again, as soon as the Elasta-Tuff™ 6000-AL-HS first coat becomes solid enough to brush, apply the second coating.

Bear in mind that both the CPES and the Elasta-Tuff™ 6000-AL-HS are volatile, activated coatings and if you are applying them in an enclosed space we highly recommend the use of a respirator capable of filtering organic solvent fumes (we sell a very nice one, if you don't have one at hand). OSHA also recommends that when using polyurethane's that contain isocyanates (as Elastuff 120 and Elasta-Tuff™ 6000-AL-HS does) that the respirator also be fitted with the particulates add-on filters.

Hope this is helpful, and if you have further questions, feel free to come on back.