revisiting the venerable grunch pad...

Decked Canoes, Open Canoes, as long as they're canoes!

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pblanc
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Re: revisiting the venerable grunch pad...

Post by pblanc »

I have tried the ABS dissolved in acetone technique on a couple of boats and wasn't too happy with it. But it is entirely possibly that I did not apply enough coats or wait long enough between coats. The immediate result looked reasonably good but the stuff started to chip off with the first use.

I never tried covering it with a layer of S 'glass, however, and I can see how that might work pretty well.
raftingbum
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Re: revisiting the venerable grunch pad...

Post by raftingbum »

I use more acetone which means I have to apply more coats, but it allows the layers of Abs goo to melt/combine well with the royalex and other layers goo. It keeps it from pealing or scraping off in chunks. And the sglass is awesome.
milkman
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Re: revisiting the venerable grunch pad...

Post by milkman »

I don't measure it quantitatively. I first mix the resin and hardener together thoroughly and then drop graphite powder in by scooping a bit out of the can at a time on the end of a stirring plastic spatula or popsickle stick. I stir each small scoop of graphite in before adding more and continue until the graphite powder makes the epoxy just a bit thicker.
Sounds like my cooking. Thanks for the graphite advice!
jknkboaters
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Re: revisiting the venerable grunch pad...

Post by jknkboaters »

sbroam wrote:7 boats times 2 kevlar pads each... We looked at the West Systems coverage specs :

http://www.westsystem.com/ss/coating-quantity" onclick="window.open(this.href);return false;

A quart is supposed to give you about 100 SF on a porous surface. I'm looking at a little over a square yard of felt, call it 10 SF. I can see how wetting out felt could be more, but how much more? What do you think?
I recently put in a Kevlar felt pad using epoxy resin. The Kevlar pad I used was 6" x 12" (small for grunch pad, yours will probably be bigger). It took about 6 ounces of epoxy.

So a quart equals 32 ounces of West System and some hardener 11 ounces = 43/6= 7 grunch pads. So you need more than a quart, probably 2 quarts for sure.

I have a tip for installing grunch pad, after saturating the felt with epoxy using a disposable foam paint brush. Place Clear Plastic Wrap (the type to wrap food leftovers, clings to itself) over the pad and then use a roller to get out the air bubbles. Leave the plastic wrap on till epoxy cures.

Probably be best to do the canoes one after another to keep down wasted epoxy.
That being said, that is a lot of canoes to take on in one afternoon.
pblanc
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Posts: 535
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Re: revisiting the venerable grunch pad...

Post by pblanc »

jknkboaters wrote:
sbroam wrote:7 boats times 2 kevlar pads each... We looked at the West Systems coverage specs :

http://www.westsystem.com/ss/coating-quantity" onclick="window.open(this.href);return false;

A quart is supposed to give you about 100 SF on a porous surface. I'm looking at a little over a square yard of felt, call it 10 SF. I can see how wetting out felt could be more, but how much more? What do you think?
I recently put in a Kevlar felt pad using epoxy resin. The Kevlar pad I used was 6" x 12" (small for grunch pad, yours will probably be bigger). It took about 6 ounces of epoxy.

So a quart equals 32 ounces of West System and some hardener 11 ounces = 43/6= 7 grunch pads. So you need more than a quart, probably 2 quarts for sure.

I have a tip for installing grunch pad, after saturating the felt with epoxy using a disposable foam paint brush. Place Clear Plastic Wrap (the type to wrap food leftovers, clings to itself) over the pad and then use a roller to get out the air bubbles. Leave the plastic wrap on till epoxy cures.

Probably be best to do the canoes one after another to keep down wasted epoxy.
That being said, that is a lot of canoes to take on in one afternoon.
Yeah, Kevlar felt soaks up an enormous amount of epoxy. That's why I don't use it. Personally I don't think the strength gained is nearly worth the expense.
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