JEM Watercraft
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Graphite & Epoxy mix for the boat bottom
http://www.jemwatercraft.com/forum/viewtopic.php?f=7&t=134
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Author:  hairymick [ Mon Jun 11, 2007 5:51 pm ]
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G'day Zeb,

250 grams will be more than enough :D Ratio of graphite to resin is about 20 percent graphite. It will take about 100 mls of resin graphite mix to cover the bottom and up the sides two inches. That makes it about (by volume) about 20 mls of graphite per mix.

Allow at least 3 coats and roll it on really well. - back and forth lengthways and cross ways and it spreads pretty well. Between coats, I like to run over the previous coat with a draw - scraper to remove any lumps or bumps.

Image

Author:  Oldsparkey [ Mon Jun 11, 2007 7:15 pm ]
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If you would add the graphite to the cup , then add the resin and stir it really well , then when you think you have it mixed stir it some more , when you are sure it is well mixed then add the hardener and stir it in really good ..... Now it is ready for the bottom of the boat without any lumps in it.

Chuck.

Author:  zeb [ Tue Jun 12, 2007 3:10 am ]
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Thanks fellas
I was a bit apprehensive about putting black goo on the bottom of the boat but from what Ive read it now seems a logical step in the building process :)
all the best zeb

Author:  Kayak Jack [ Tue Jun 12, 2007 11:30 am ]
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Zeb,

www.RAKA.com sells the graphite. It's another one of Chuckie's ideas that (finally)worked out.

Author:  zeb [ Tue Jun 12, 2007 2:59 pm ]
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Cheers Jack
I managed to order some today.
Would I apply the three coats after I fill the weave or could these be incorporated into filling it?
thanks again Zeb

Author:  Oldsparkey [ Tue Jun 12, 2007 3:09 pm ]
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I'm not Jack.... Thank God for that. :lol:

Do the epoxy saturation for the base coat on the wood , then do your glass work. After you have the boat the way you want it .

The last thing you do is to add the graphite and epoxy mix , the very last thing since nothing will stick to it but more epoxy and graphite , graphite by itself is a lubricant. Better words would be a slippery item and the epoxy is what holds it in place. The graphite is what lets you slide over stumps , logs and anything else the epoxy gives it the strength to do that.

If you don't like the gloss black when it is done then you can sand it (Lightly) and it will become a gray color and even slipperier. What you would of done is to remove the outer coat (layer or skin ) of epoxy exposing more of the graphite.

If you decide to do that ...(sanding by hand ) Look out it is really messy and everything will have a black dust on it , including you till you put the boat in the water or wipe it down with a wet rag. They only do this final step on boats for racing and since my boats don't go that fast ... I leave out this last step of sanding it.

Chuck.

Author:  zeb [ Wed Jun 13, 2007 2:13 am ]
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Thanks Chuck
Next dumb question!!!! how do you you Guys scribe the line (bow line?)to mask off,do you follow the shape of the bottom chine?
Thanks again Zeb

Author:  hairymick [ Wed Jun 13, 2007 3:30 am ]
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G'day Zeb,

I am a rough bugger.

On the piurogues, I just measure up from the bottom 2 inches and mark a line in pencil.

On my southwind, I just followed the seam on top of the bottom most side panel.

I think Chuck runs a string line from a point on the bow to a point on the stern and follows that.

Author:  zeb [ Wed Jun 13, 2007 2:10 pm ]
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Cheers Mick
If the rain ever stops Im ready for action!!!
All the Best
Zeb

Author:  Oldsparkey [ Wed Jun 13, 2007 2:24 pm ]
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Lately I have gotten lazy and just run some masking tape a few inches from the bottom along the side matching the shape of the boat. As long as the ends of the tape match up at each end I figured it is right. I do a guestiment on how much water the boat will draw with the camping gear and myself in it and move the tape up about a half of an inch.

In the past I have tried doing these.
If I am luckey enough to have someone along when I test paddle the boat then I try to talk them into marking the side of it for me while I am in it or have them paddle it while I take a good look.
If no one is around then I will ease my hand over ( keeping the boat level ) the side till it touches the water and then run my hand on down till it hits the bottom of the boat remembering the approximate distance.

Chuck.

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