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Your new canoe will weigh 38 lbs natural, or 44 lbs painted, what do you prefer?
Natural all the way, baby, I like the look! 33%  33%  [ 9 ]
I don't really prefer natural, but I want a lighter canoe! 30%  30%  [ 8 ]
Give me paint, a nice traditional colour! 19%  19%  [ 5 ]
Might as well make her real pretty, two tone please! 19%  19%  [ 5 ]
Total votes : 27
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PostPosted: October 23rd, 2009, 9:04 am 
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DC,

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(and I think the guys who think 3 coats of marine enamel weigh only a pound, should weigh their boats before and after, because I am not sure that would be the case.)


Well, I painted two canoes this way and after weighing with scales before and after, the weight increase was only about a pound. I used those disposable foam rollers which put on thin, even coats... brushing the enamel on might have been heavier.

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PostPosted: October 23rd, 2009, 9:40 am 
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Wow!

as I said, I wasn't sure, but I am going to toss that in the back of my mind, as to perhaps investigating the cost and suitability for manufacturing.... vis can it be sprayed? at what cost? how thick to cover evenly? etc.

I think that the cost vs gelcoat is the reason that manufacturers don't use it, but I will look into that.


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PostPosted: October 23rd, 2009, 9:57 am 
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davidchiles wrote:
Wow!

as I said, I wasn't sure, but I am going to toss that in the back of my mind, as to perhaps investigating the cost and suitability for manufacturing.... vis can it be sprayed? at what cost? how thick to cover evenly? etc.


Of, course it can be sprayed. Thinner and more even coats are possible that way.

Quote:
I think that the cost vs gelcoat is the reason that manufacturers don't use it, but I will look into that.


No, it goes way back to the early lamination methods used for building power boats and such. They are just stuck doing it that way. It's not all that expensive, and a heavy gel coat is a boon on a power boat anyway. It just adds unneeded weight to a canoe.

Paint gives about 400 sq.ft/gallon when carefully rolled on and tipped off with a foam brush. You get even better coverage if you spray it on. That's a lot of coats on a 65 sq.ft. canoe. It's about 45-50% volatiles, so all that weight goes into the good old atmosphere, leaving only the alkyd resins and pigment on the canoe.

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PostPosted: October 23rd, 2009, 10:16 am 
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Dave, check out the Dragonslayer thread. John Winters just confirmed what I've been saying, so I'm not just pissing into the wind here. He even dropped a couple of top brand product names for you to bring to H2O to discuss.

Lot's of the best small builders are going this way. Custom colors are easy if you go to a good body shop. My guy has a system to just dial in any color, even matches faded paint on cars.

JWinters wrote:
Use no gel coat. Paint all yur boats with two part polyurethane like Imron or Awlgrip. You could probably work a deal with a local body shop to do the painting. Much higher quality than gel. Retians gloss better, does not craze,\ or crack, lighter, and more colours. Lots of different reds. :D

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PostPosted: October 23rd, 2009, 10:57 am 
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thanks! I know you werent pulling my leg, and I will look into it, I think the deal is the thickness applied versus cost, as paint is essentially purchased by volume or mass, and it just depends how much is applied, going with similar volume to gelcoat, the cost would be astronomical, as a fairly thick layer of gelcoat is used, hence greater mass and volume, but if 2 part poly like he mentioned can be applied much thinner, then cost could be brought down


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PostPosted: October 28th, 2009, 8:58 am 
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Greek Compromise?

If I were doing it again, and I'm not, I'd gel coat the waterline patch, maybe three lbs of the seven, to have the abrasion protection and skin coat the sides, letting the carbon show. Kevlar makes a punk outer layer anyway.


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PostPosted: November 1st, 2009, 9:21 am 
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What is "poly" which was mentioned several times?
Could you please provide a full name/description?


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PostPosted: November 1st, 2009, 9:46 am 
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Two-part polyurethane paint... Part "A" and Part "B" are mixed together and then applied as paint. Very thin, light and tough... the brand I used was Endura, available at Smithcraft on the Queensway at Islington, West Toronto.

White is about $50 and red is the most expensive at about $100 a liter, with the other colors mixed to order. The main downside with Endura is the cost. Interlux makes a two-part poly, Interthane Plus, that is also available in small quantities for canoes. IIRC, it is also expensive.

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PostPosted: November 1st, 2009, 10:56 am 
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frozentripper wrote:
Two-part polyurethane paint... Part "A" and Part "B" are mixed together and then applied as paint. Very thin, light and tough... the brand I used was Endura, available at Smithcraft on the Queensway at Islington, West Toronto.

White is about $50 and red is the most expensive at about $100 a liter, with the other colors mixed to order. The main downside with Endura is the cost. Interlux makes a two-part poly, Interthane Plus, that is also available in small quantities for canoes. IIRC, it is also expensive.


Hey bean counter, we need this kind of info at DragonSlayer as well. :wink:

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PostPosted: November 1st, 2009, 5:21 pm 
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frozentripper wrote:
red is the most expensive at about $100 a liter, .

another wow! I got Ephipanes red at Noah's for "only" $60/L as I recall.

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PostPosted: November 1st, 2009, 5:33 pm 
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I don't know what Millbrook and Bluewater used on the outside to give some color and UV screens to my boats, and I don't know what Dagger used when they colored my c-1 slalom boat red, but the stuff is thin, hard, light, and obviously did not cost much weight. Is it "paint"?

Slalom boats are colored for show, but if that coloring weighed much, they would skip the "paint" and put in an equivalent amount of materials that would make the boats stiffer, tougher, or more durable.

So, my argument, based on four boats I own that have some sort of light weight coloration, is that the weight differences depicted in the opening poll may not be realistic. It may require less than half that to get some nice, tough, color.


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PostPosted: November 1st, 2009, 7:46 pm 
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wotrock wrote:
frozentripper wrote:
red is the most expensive at about $100 a liter, .

another wow! I got Ephipanes red at Noah's for "only" $60/L as I recall.


Large commercial canoe manufactures can buy top quality two-part poly for a fraction of those prices by purchasing in bulk.


Another problem with the use of paint is keeping it dust free while it hardens. Gel coat hardens inside the mold where dust can't reach the surface. Anyone who has ever varnished or painted a canoe can attest to the difficulty in keeping dust off the surface. But it can be done. If not, how would you ever manage to get your car painted after a collision?

I still think it's a case of sticking with what you are familiar with. Too bad, because we could all tougher and more durable canoes if the makers would add an extra layer of cloth instead of the same weight in utterly useless gel coat. Then paint it with UV opaque two-part poly that is hard as nails, resists abrasion, is easily repairable and weighs next to nothing.


I made some calls locally and found an auto body shop that will prep and spray my 16 1/2' skin-coat Kevlar boat with two coats of UV resistant two-part poly top coat (clear coat) for $200. I'm sure when I show up with the boat on top of my car all prepped and masked off the price will come way down. I think I'm going to take him up on the offer, even if I have to pay the full two bills.

Too bad the fine canoe company that built this wonderful boat didn't do it when it was made. That way, I wouldn't be paddling around in a boat that's all streaked in "UV Brown". But with $2000 invested in the boat and with a current replacement price near $3000, at least I can stop further degradation of the fabric and still have a <40# canoe on the portage trail.

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PostPosted: December 11th, 2009, 2:01 pm 
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I'm a gel coat guy. Certainly it adds weight, but I would argue that it does not necessarily add the weight that the original poster mentioned. It has to do with how much gel coat is applied. A careful builder like Dave Curtis, puts a thin layer of gel coat on his boats. Too thick and the gel coat will crack as the boat flexes. On my composite boats, gel coat protects the vital parts from UV damage. Most paints are not as hard as gel coat. An exception would be Tank Coat and similar products which are very hard. Even on a w/c canoe, it's not the paint, but the filler that adds the weight...linseed oil and lead. Gel coat or paint, weight varies with color. White is what I usually prefer. Light weight, does the job and doesn't show scratches.


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PostPosted: December 11th, 2009, 6:45 pm 
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Thanks for all the comments!

the initial poll and posting was done to keep things fairly simple, as gelcoat applied thick enough so as not to see through it has a significant weight to it, and I was initially curious as to how many persons wanted an unpainted canoe, versus a painted one (I am using 'paint' to indicate gelcoat colour finish, which like the poly paints is also a two part finish system)

I think gelcoat is used because it is the cheapest and easiest method of imparting a tough, durable, and colorful outer layer on a boat, and has the advantage of being sprayed into the mold first, rather than applied as a last step.

I was thinking, to keep costs down, perhaps gelcoat would be ideal for fibreglass or basic glass/kevlar boats, but full kevlar and kevlar/carbon boats (which command higher prices of course, along with lower unit production) might be painted with two part poly paints as many respondents have suggested.

Cheers, and thanks for voting!


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PostPosted: December 12th, 2009, 1:48 am 
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David, it was a an interesting question to be raised. Having raced sailboats for a number of years, I think it is important to remember that gel coats and poly paints have a variety of different formulas. While many paints might perform well on a canoe, some, especially Imron, has been a disaster on boats that are moored. Many paints, and gel coat too, for that matter, are porous. Long exposure to water in a lot of paints can cause the paint to blister and peel. The other issue is the application. In racing sailboats, a smooth finish is of prime importance, and cost in some cases is no object. Having been down this road, I can say that spraying(in my case Tank Coat), is difficult and still there is a lot of wet sanding to be done before the finish is fully cured. Gel coat, is easy in that regard.


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