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 Post subject: Vinyl Ester vs Epoxy
PostPosted: July 12th, 2006, 3:47 pm 
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Joined: August 22nd, 2002, 7:00 pm
Posts: 16
Location: sudbury, Ontario canada
Is there an engineer in the house?

I am looking at a new canoe and have been told by one salesman that Epoxy layups are superior to Vinyl Ester for strength and durability. I am considering a
Nova Craft Blue Steel (vinyl ester), a Langford Kevlar (vinyl ester), and Western Canooeing Clipper (epoxy). Any comments on these layups would be appreciated.
I curently have a Nova Prospector 17 in Kevlar Cap (vinyl), 60 lbs, that has been great. Looking for something lighter but tough enough to bounce off the odd rock if need
be.

Thanks, Bushpig


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PostPosted: July 12th, 2006, 8:05 pm 
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Joined: March 23rd, 2005, 1:41 pm
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Location: Grand Marais, MN
Yep, true. But in canoes either layup should be just fine. Buy the canoe that you like to paddle.


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 Post subject: Probably true but
PostPosted: July 13th, 2006, 3:41 am 
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Joined: July 18th, 2003, 2:39 am
Posts: 537
Location: Enkhuizen
Typical salesman talk to use a word like 'superior' when the better
words would be "somewhat better" IF you don't take into account
that a good epoxy layup costs (a lot) more too. If that's worth it?
Depends. For _equally_ good designs and layups, I would possibly
spend the extra money on an epoxy lay-up, but I would insist on a
(two part) PU coating too then (even more costly). But I am used to
spend (much) more money on canoes, because they have to be imported
from far away :-(

Dirk Barends


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 Post subject:
PostPosted: July 13th, 2006, 5:54 am 
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Joined: October 26th, 2004, 12:25 pm
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Location: The Netherlands
Vinylester is - still - the most commonly used resin for composite canoes, and used by highly rated manufacturers like Bell, Wenonah, Mad River, Swift, a.o.
Major reason for this is:
a) lower raw material costs compared to epoxy
b) proven to be a adequate resin for all composites used in canoe building
c) much easier to work with (lower manufacturing costs)

Yes, epoxy has proven to give a stronger hull at comparable weight. But it all depends on the care and quality of the builders...

The epoxy which claims to be superior to vinylester is not the epoxy types used for hand layup wood strip canoes... it is of a much different system which requires heat curing in an oven. Since epoxy is much more difficult to lay-up, mistakes are more easily made... bonding errors with the cloth can occur.
Epoxy has a significant better bonding to the reinforcement cloth, but the exact resin/harder ratio is very important... for vinylester this is of less importance.

If correctly mixed/applied/cured, yes Epoxy offers a stronger/stiffer canoe at the same weight. But once again, vinylester has proven it's use.

Michel, The Netherlands


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 Post subject:
PostPosted: July 13th, 2006, 7:42 am 
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Joined: December 29th, 2002, 7:00 pm
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Location: Bancroft, Ontario Canada
Quote:
Looking for something lighter but tough enough to bounce off the odd rock if need be.


Souris River has a reputation for building light and tough with epoxy resin, with the ribbed hull design said to provide the right combination of flexibility and stiffness for increased resistance to rocks. I have an old ribbed fiberglass canoe and would agree that the design feature makes for a fairly tough hull that absorbs impacts better because of the flexibility. There are SR canoes for rent and sale at White Squall near Parry Sound and you'll be able to test-paddle there.

Canoes built with epoxy are also said to be longer-lasting and repairs made with epoxy and glass may be more reliable with less chance of delamination occurring with time. If were to lay out the $$$ for a quality canoe such as an SR, I'd want it to last 30-40 years if stored under a roof out of the elements. I wouldn't buy top-quality if the storage was going to be in the sun every day, under snow loads, etc.

Anyway, another option. The spectra canoes are also said to be very durable but not as light as the SRs. The amount of portaging you have to do could influence how light things need to be.... good luck.

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 Post subject:
PostPosted: July 13th, 2006, 8:41 am 
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Joined: December 15th, 2001, 7:00 pm
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Location: Shelburne, Ontario Canada
Having applied both epoxy and polyester resins, epoxy in an industrial setting, I don't consider the two anywhere near equivalent. I've seen a polyester resin canoe broadsided on a rock and almost snapped in two on it's maiden voyage, on a rock in a little swift, it wouldn't be fair to call it a rapid. The epoxy resins I worked with were so tough even a very thin layer has to be cut, I can rip some polyester coatings with my nails. My latest canoe is polyester, but only becuse i couldn't find an epoxy second hand. I wrote at least 5 outfitters and no one had an epoxy boat they wanted to part with. That says something. If you want to buy a new canoe and you are willing to pay the money go with epoxy anytime you have the choice.

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 Post subject:
PostPosted: July 13th, 2006, 9:17 am 
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Location: Aurora (Borealis)
Fellow Resin Inhalers,

I assume that epoxy layups are somewhat less likely to sustain damage than vinylester boats in the same circumstances. But if they do get minor damage, can they be easily repaired by their owners? (I'm talking surface damage where the cloth becomes exposed.) Or do they need to be dealt with in an "industrial" setting like you mention, normhead?

-JF-


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 Post subject:
PostPosted: July 13th, 2006, 3:04 pm 
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Location: Shelburne, Ontario Canada
The industrial setting we used them in was a spray booth with a 25 hp exhast fan 100-psi spray guequipment. There is absolutely no reason if you can obtain the materials you can't repair effectively in your garage or outdoors in the summer. You just need to have adequate ventilation. The problem is finding the repair materials. Most of the "epoxy" materials in the stores are actually poly products. The stuff we used to spray came in gallon cans an was extremely expensive. You had to have a gallon of epoxy and a gallon of hardener, so it was a minimum two gallon mix.

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 Post subject: Re: Vinyl Ester vs Epoxy
PostPosted: July 14th, 2006, 1:00 am 
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Joined: September 16th, 2002, 7:00 pm
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Location: Vancouver, British Columbia Canada
bushpig wrote:
....I am considering a
Nova Craft Blue Steel (vinyl ester), a Langford Kevlar (vinyl ester), and Western Canooeing Clipper (epoxy). ....


Are you sure the Clipper is epoxy? I was under the impression they weren't. Unless they've changed the construction or selling special ones.

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 Post subject:
PostPosted: July 14th, 2006, 2:29 am 
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johnfrum wrote:
Fellow Resin Inhalers,

I assume that epoxy layups are somewhat less likely to sustain damage than vinylester boats in the same circumstances. But if they do get minor damage, can they be easily repaired by their owners? (I'm talking surface damage where the cloth becomes exposed.) Or do they need to be dealt with in an "industrial" setting like you mention, normhead?


Yes. In fact epoxy resin will bond to most types of fibreglass so likely you could use it on your existing canoe. Check at a marine shop or maybe someone here will know. West System usually has free literature. Their products seem pricey but the dispenser pumps are a handy way to get the resin/hardener ratio perfect. Their filler material for "faring" saves a ton of sanding time too.


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