: Was glad you mentioned GACO site as was just starting to wonder where these
: exotic coatings came from. Was very interseting. If I got it correctly it
: looks like Neoprene and Hypalon are pretty expensive to use vs their 2
: part urethane over ext paint like the Willow boats, something like 2
: gallons to cover a kayak of roughly 50 sq ft?

I don't believe that is a totally accurate estimate. While the hypalon and neoprene materials are expensive by themselves, the urethane is not exactly cheap.

I'm not sure where you get the idea that it takes 2 gallons to coat a kayak with hypalon, but let's go with that number. It doesn't seem too far out of line if you see where Gaco figures 400 square feet of coverage at a 1 mil. coating. By my math I would have figured that a gallon would give me 8 coats, 3 on the inside and 5 on the outside. However, if the thick polyester material soaks up this stuff -- and I hope that there will be a lot saturating the fabric, then I can see where I'd need more coating.

The last time I saw a price list from George Dyson he had some "closeout" colors of hypalon at about $50 a gallon. Gaco wants $66 for neoprene and $74 to $134 for hypalon, depending on the color. I've seen estimates of $6 to $13 a yard for the polyester fabric. The Gaco urethane is $99 for 1/2 gallon, which should be fine for the one or two coats needed with that system. #10 duck is $4 to $7 a yard. Elastomeric roofing material, and outdoor polyurethane (both local hardware store items) go for about $20 to $25 a gallon.

So, the costs for a 17 foot boat, with 6 yards of fabric would run about:

1) hypalon over polyester: $136 to $347. figuring the lowest with hypalon at $560 a gallon and the least expensive cloth. The highest is with Gaco's most expensive color, and cloth at $13 a yard.

2) neoprene over polyester: $168 to $211. I used the $66 a gallon price from Gaco for the neoprene. If you can find some cheaper, go for it.

3) urethane over polyester: $155 to $203. This includes the fabric, a gallon of outdoor polyurethane, and a half gallon of Gaco's urethane for a topcoat. The price here is nearly identical with neoprene, and might even be more than hypalon. The hypalon prices estimates are the least reliable as the low estimate relies on what may be out dated pricing information, though. However, if you only use 1 gallon of hypalon or neoprene, then this would be higher in cost!

4) elastomeric roofing naterial over canvas: $44 to $61

5) outdoor oil paint (or latex) over canvas: $44 to $61, but if you aren't too critical about the color you can frequently buy mis-tinted paints for under $6 a gallon, which would bring the low side estimate down to merely $30. This is by far the least expensive way to go.

You could also cover canvas with hypalon, neoprene and urethane. The price would be about that same, except for the few dollars difference between the cost of the base fabrics. Subtract $12 from the lowest cost estimates for polyester if you use the lowest price canvas. The highest price canvas is about the same coast as the cheapest synthetic, so the overall price would be about the same. Coating both sides of the canvas with hypalon or neoprene and probably urethane, too) would protect it from rot for a long time.

When buying or pricing fabric, if the difference in price is $1 a yard, for the 6 yards you are buying this is just not a big difference. Even a $5 a yard difference in price is only going to be a $30 difference in the overall cost of the skin. That is, $7 a yard vs. $12 a yard is $42 vs $72 for fabric. These differences are already reflected in the range of prices given above.

There are very valid reasons with going with a thinner or cheaper skin. If you are on a strict budget, or trying out a design concept, or want a lighterweight boat and can deal with less durability, thinner fabrics generally cost less than thicker ones. they'll also soak up a bit less of whatever waterproofing material you coat it with.

While canvas and paint are the least expensive combination, the service life would be the shortest. I'd expect 5 years of service from canvas, and twice that or more from polyester and neoprene or hypalon. I'd be interested in hearing actual data on how long some of these combinations actually DO last, though. Oldest I've personally seen was a 25 year old Klepper hull, and it looked pretty darn good -- but it wasn't used much.

Hope this helps.

PGJ

p.s. With careful shopping for the lowest cost synthetic skin, you'ld still have $50 to $65 to spend on the wood for frame parts to build a Putz Walrus, and still keep the whole boat's cost under $200!

p.p.s. All prices in US dollars, and I didn't figure in any sales taxes.