: I'm using a rubber roofing material instead of paint. It is latex
: (natural?rubber) based and cleans up with water, but when allowed to cure
: in the sun becomes a very tough, waterproof which is suposed to last for
: 20 years on roofs -- so I guess it is not only very resistant to cracking,
: but also highly resistant to UV. There are several similar products on the
: market sold under the names of Sno Cote, Snow Coat, Sno White, Snow Roof,
: etc. Look for an elastomeric roofing material. I think I paid about $20 a
: gallon, which is more than what cheap latex house paint sells for, but
: still in the neighborhood of exterior oil paints. There is a similar
: material that is black which one of the contributors to this board used as
: a base coat on his kayak. I'm just using the white stuff without an extra
: base.

: I was painting some trim parts for the inside on my kayak with a polyurethane
: topside marine enamel and, since it was also white I spread some over a
: section of the well cured sno-cote covered hull. Write back to me in a
: year or two and I'll let you know how durable that has been. So far it
: seems to be bonding very nicely, and the polyurethane gives the fabric a
: beautiful shine.

: Oil based paints have been the traditional coatings for canvas boats. The oil
: soaks into the fabric so you just have to apply the paint from one side.
: Hint, working from the outside will be easier . The basics of oil paints
: are these: Linseed oil will coagulate and harden when allowed to oxidize
: and dry. (Chemists call this polymerization) Heat and some chemicals (
: called driers or drying agents) can speed up the process. Oil paint is a
: mixture of this oil, a thinner (which evaporates) and a pigment which
: givesw tha pint its color. Some paints also have fillers -- cheap and
: relatively inert materials that give the paint some body and may help to
: stretch out a relatively expensive pigment material. For example, common
: chalk may be ground up and added to white paint instead of using a lot
: Titanium Dioxide as the white pigment. Chalk is a lot cheaper. while such
: a combination might make a "cheap" house paint, it is actually
: supposed to be a good thing for kayaks, ans the additional chalk, while
: not doing much for the color, helps to fill in the weave of the canvas
: material, and make it smoother. In his book on canvas covered boats,
: George Putz recommends adding additional chalk to the paint as a filler
: for the first coat for that reason. He also recommends adding a fungicide,
: but I can't remember how much. ( I didn't add a fungicide to my roof
: coating and I'm seeing some stains that could be fungus -- next time I'll
: know.)

: Latex paints should be fine, too. Oil based paints have a reputation for
: being more flexible when they dry, and the roofing material I used is
: incredibly flexible when cured.

: The thicker the paint the better the waterproofing, but apply thin layers
: over a long period of time. A fresh coat of paint each year at the start,
: or end, of the season is nice. It seals the pinholes and minor cracks that
: give slow leaks, and builds up a smooth finihs that hides the woven nature
: of the fabric.

: Don't worry about using Bondo to hide the edges of the fabric, and don't rush
: things. Next year, or the year after, after you have a few layers of paint
: on the boat, the paint film will be hard and dry, and thick enough to sand
: smmoth.

: Hope this helps.

: Paul G. Jacobson

We can always count on Paul to give us a thorough analysis on any subject. Nice thought, by the way. I'm currently building a canvas skin boat. When you apply Snow Cote, Do you thin it out? Do you brush it on, roll or any other application you prefer? Any particular brand of polyurthane you recommend? Thank you for your time and effect to study and come up with a scientific deduction .