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 Post subject: Can Epoxy be heated and reshaped like polyester?
PostPosted: Wed Oct 15, 2008 3:53 pm 
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I made a great board with a flip tip and hate the flip


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 Post subject: Re: Can Epoxy be heated and reshaped like polyester?
PostPosted: Wed Oct 15, 2008 4:23 pm 
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Doubt it, but do not know...

try it, if not just cut the offending flip off?

we talking foam? or wood?

details, details, it's about the details....


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 Post subject: Re: Can Epoxy be heated and reshaped like polyester?
PostPosted: Wed Oct 15, 2008 8:49 pm 
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pvc core hand layed 8oz. X 2 ,1.4oz.X1
I want to keep the shape,
but lower point of entry


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 Post subject: Re: Can Epoxy be heated and reshaped like polyester?
PostPosted: Wed Oct 15, 2008 9:03 pm 
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light that bitch up, see what happens...

If not, maybe you could mold a wedgee, ugly is not such a bad thing...

good luck


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 Post subject: Re: Can Epoxy be heated and reshaped like polyester?
PostPosted: Wed Oct 15, 2008 11:02 pm 
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hahah Funny Story for this one

A mate of mine sails a Foiling Moth Sailboat and he's built the boat and his foils. He didn't post cure the foil plade properly and left it in the sun one day and because of the way he left it the foil saged a bit when it was heated up and the sun "cured" it while it was in that shape. In the end of the day he loft it in the sun again and clamped it down to a flat table and it came true, bit wonky but true

If you could do it in a controled way is anyones guess, but I had a good giggle at my mate about that one.


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 Post subject: Re: Can Epoxy be heated and reshaped like polyester?
PostPosted: Thu Oct 16, 2008 5:12 am 
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I think if you are using something intermediate modulus, non-post-cured like west 105, system 3 or :thumb: Resin Research, you can probably do it. Would be fun to try.
How good a shape result and how much strength would be left, harder to guess.

I would try first, find out what range of temps is between post curing and decomposition of the core and the resin matrix. Then see how the core and resin thermal expansion coefficients match up within that range. If they are close, good- maybe you can just heat the whole board up and mash it into a rocker table. If the expansion numbers are "sort of" close, you can probably get away with it, since it is a thin core. On the other hand it could crack .

If your numbers don't match well, or it just doesn't work, then next idea I would try depends on how you built it.
If you forced the rocker in on a table during layup, the fibers will be slightly prestressed, so you might be able to gently grind off part or all of the deck lamination near the tips and have the tips spring back naturally to the base rocker line. A little heat aplied to the deck could help it along. Hopefully if you have the base rocker of the board still on a table you can then relaminate the tips on the deck side and lock it all in on the table. Would be cool to not have to redo the edges and bottom glass...

If this didn't work and I had the time, or if rocker and flip was carved/shaped in rather than forced in, I guess I would start grinding on the bottom as well until it got floppy enough, then reglass the tips at top and bottom. No idea if your results would be strong and pleasing to you, depends on a lot I guess. If you do reglass, keep a good long feather edge on the layers. I think the standard for scarfing in glass is like 20 or 30:1. This might all get to be too much trouble though.

But if the board rides "ok" just not your style, maybe you could can sell it for enough to buy materials and make another one in only a little more effort. But I think the first step is worth trying for sure.

Good luck, caveat this advice is partly hypothetical, haven't built that many boards... Did have one lose rocker in a hot car though :oops:


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 Post subject: Re: Can Epoxy be heated and reshaped like polyester?
PostPosted: Fri Oct 17, 2008 3:53 pm 
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BWD wrote:
.. Did have one lose rocker in a hot car though :oops:


Was it an epoxy board?
I use System 3 surfboard/sailboard resin
the poly board I did reshaped at about 140 degrees
has held for 3 yrs.
thanks


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 Post subject: Re: Can Epoxy be heated and reshaped like polyester?
PostPosted: Fri Oct 17, 2008 4:37 pm 
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It was my first board, epoxy/ply, west 105. I think the mix was off, so it went off too slow or incomplete cure. I glued it up on a cool spring night, took it off the rocker table the next morning and threw it in the jalopy, the day was a hot one, and when I got to hatteras that night the rocker was nearly flat. :lol:
And of course, I got skunked.
It was hilarious trying to wakeboard on it though - nobody could ride it for more than a minute.
Lesson: mix carefully, cure completely.
Eventually I routered off most of the deck, redecked it and and it is fine now.

That is cool that you could do that with PE, had no idea.
I bet you can do it on epoxy, just would be careful heating it over foam, since the foam has air inside and will heat at a much slower rate than the skin. But if you heat it slow and the materials are well matched, hopefully it works. Also, I would try lower temp and higher force rather than the other way around. Great if you could clamp it or vacuum it to a rocker table, maybe with a heat lamp at each end, then leave it to cool for a day or two before unclamping. My theory on that is you are breaking some bonds and may make a few new ones at that temp, but it is not like a whole new reaction for sure. You would be relying on forcing the shape, and maybe picking up a few new bonds of some type as it cools down. Don't start a fire.
Maybe you can go to baja and use solar heat ;).


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 Post subject: Re: Can Epoxy be heated and reshaped like polyester?
PostPosted: Fri Oct 17, 2008 6:10 pm 
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I just will use a hot box with a propane catylitic
pretty hard to heat and keep a very big area hot for very long

I just got my nose a little too high
and want it to have a lower point of entry
the poly board took about 6 hrs.to heat completely
and a bunch of wood clamps.

never have heard this about epoxy

I would think your lay-up was uncured


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 Post subject: Re: Can Epoxy be heated and reshaped like polyester?
PostPosted: Fri Oct 17, 2008 10:18 pm 
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Definitely uncured. And bad mix because part of it was still uncured the next week when I did "deck replacement surgery."
I really don't know if you can get a good result.
If it were me I might check swaylocks forum too before trying.
Good luck.


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