> I have been looking at some pages and posts on various skin on frame
> kayaks with some thought of building my next boat this way. I have come up
> with some questions.

> Using canvas for the skin and Elast-o-Seal and Snow Roof for the coating:

> should the surface which will be the inside of the skin be coated with the
> Elast-o-Seal before stretching the fabric on the frame? Don't know, but canvas is a great absorber of water and I've never seen a boat that doesn't get some water inside. Most advocates of canvas suggest that the coating should be sufficiently thinned to fully penetrate the cotton when applied from the outside. Raw canvas mildews and rots fairly easily. The space between the skin and the stringer rarely gets a chance to dry out.

> I have used Snow Roof in another application, without Elast-o-Seal, and
> was not impressed by its gripping ability. Does anyone have experience
> with it in this application?

> For boats of the same design, will stich & glue or skin on frame
> produce the lightest boat? (I built two rigid Folbots, a 17' single and
> the 14' Glider, back when Folbot marketed kits. The boats were anything
> but light - about the weight of comparable plastic boats.) That depends on you, if you use 2x4s for stringers it wont be light. I've built 2 Putz style boats and one is forty pounds (with canvas) and the second is 35 lbs (with PVC coated polyester). This is about 1/2 to 2/3 the weight of a production boat.

> I have seen references to using cedar for the stringers. Cedar is light,
> but not very strong, i.e., a 3/4"x1" stringer of cedar can be
> easily broken by hand. Unless I am missing something, I should think a
> stronger wood would be advisable if the boat is to be banged around a bit
> (as all my boats are). I used yellow cedar for all the structural parts of the boat and I can put the ends of the kayaks on saw horses and sit in it.

> For what it is worth, Daniel Smith, an art supply house with free catalog,
> carries a wide variety of canvas duck and also linen in various weights.
> They only have one synthetic fabric. Defender Industries carries some
> vinyl coated nylon cloth. Would the vinyl coating be a sufficient
> waterproofing? It could if it fully penetrated the fabric and was bonded to it but watch the strength. Cotton is fairly strong but when holed can tear fairly easily. Depending on the paint used canvas can be fairly sturdy. The polyster cloth I used is nearly impossible to tear by hand but I've not used the boat enough to determine its long term abrasion resistance. Bram
> Thanks for your help.

> Chris Luneski

> chrisl@oregon.uoregon.edu