brave
Polyester resin used on the grand majority of fiberglass production boats is extremely flamable, you’re brave using a direct flame on it.
Bill H.
Maybe polyester resin is flammable when
in liquid form and full of styrene. Once set, it isn’t any more flammable than the general run of plastics. Sweeping a torch across the surface, whether to burn off fuzz or to prepare the surface better for epoxy patching, is not risky.
By the way, I think vinylester is more common in quality canoes by far than polyester. For very good reasons.
vinylester
Vinylester may be used in a few high end canoes/kayaks but polyester is by far the most common. Costs are the reason, paddle craft is a very competitive market price wise and vinylester is considerably more epensive than it’s more common polyester cousin.
Btw, any of the esters are extremely flammable and nearly impossible to put out once the fire is started.
Do a web search for boat fires.
Bill H.
Poly/Vinyl cost and use
The best Vinyl Ester resin on the market costs about $3.00 / pound. Ordinary tooling Poly Ester costs about $2.50 / lb. A standard 14" canoe like Argosy/WildFire uses less than 14 lbs resin, so the difference in cost between Vinyl and Poly is $7.00.
WeNoNah, Bell and Swift all use Vinyl ester, as do GRE, Hemlock, Hornbeck, Placid boatworks, Savage, Vermont Canoe and Colden. That takes care of the large and craft canoe builders on the east coast. Who’s using poly?
When I was a boy, my hobby was
shooting up plastic ship models with my BB gun and then burning them. I know they burn. But there is no risk using a propane torch to flame off fuzz or to prepare for patching on a polyester or vinylester boat.
I also disagree with you about the relative use of polyester and vinylester in the boat industry. Figures? Examples? Of the quality canoes we discuss on this board, it’s hard to find an example of a builder that uses polyester. Can’t tell about Wenonah, they don’t say anything about the nature of their resin. The others use vinylester, or epoxy.
Not only is vinylester stronger than polyester, it has MUCH less tendency to hydrolize and blister than polyester. I lost an early polyester canoe to blistering.
And by now, vinylester is not a sophisticated resin. It’s widely available.
What about epoxy resin?
Souris River is the only company that I am aware of using epoxy resin. They promote this quite vigorously, claiming that epoxy resin is “many times stronger than the polyester and vinylester resins…” Can you comment on this Charlie? If epoxy is so superior, why are more canoe builders not using it?
Epoxy
– Last Updated: Dec-15-09 8:19 PM EST –
This from a jobber who sells epoxy, not VE or poly:
Epoxy will cost several 4X more, ~$13/#, for a 10% strength increase. This raises the manufacturing costs of the 14 ft hull $140!
It will require a "finishing oven" to post cure. It used to be unresistant to UV degredation It infuses in an hour compared to VE which infuses in ten minutes. Lastly, epoxy tends to become allergenic to workers.
Epoxy is fine for stripper builders, mostly due to work time, and ~ minimal fumes will not drive the wife from the home when building in an attached garage.
Epoxy is perfect for pre-preg carbon that is cured in a vacuum autoclave, [that autoclave is roughly $600K used for canoe size].
UV degradation is an issue if not painted. It requires a BagLady cover be used constantly, which is great for Sue, but not handy for recreational boats.
Strangely, the F35 fighter project is using as much infusion technology as possible to reduce costs compared to prepreg vacuum autoclave!
Bluewater also uses epoxy. Epoxy is
the usual resin for whitewater slalom kayaks.
Souris has always been a know-it-all company that tries to run down other companies to build themselves up. Their canoes are ok, though not as good as Bluewater, and no better than a lot of vinylester canoes.
Charlie, if you read this, why is vinylester thought to be much less susceptible to UV damage than epoxy? I’ll bet the difference is not large.
kayaks
Virtually all the kayaks are built with polyester.
Bill H.
time
Polyester/vinylester takes maybe 15 minutes to set up after it’s used, epoxy takes hours or days to do the same thing. Takes too long for production work to use epoxy for something as inexpensive as a kayak/canoe. Time is money.
Bill H.
I’m sure glad the epoxy I use for
patching and making parts doesn’t know that. It sure would have caused delays.
No, most of the kayaks are made
– Last Updated: Dec-15-09 9:22 AM EST –
with vinylester.
Most builders would not risk their long-term reputation by using polyester. It makes weaker laminate, and it hydrolizes and blisters with time. It costs only a little more to use vinylester, as CE Wilson pointed out, and you get a much better result.
johnrsweet.com won't even sell polyester resin any more. Only vinylester and epoxies.
Necky’s built in Thailand by Cobra Int.
use epoxy resin and are post cured. Some manufacturers have in the past used custom poly / vinylester blends to save cost.
Interesting blend. Does the vinylester
improve the polyester that much?
Does Necky believe epoxy holds to the cloths better than vinylester?
Not so sure.
I recall seeing some big name UK kayak manufacturers state on websites and catalogs recently that they use polyester resin for their standard layups.
Hype
– Last Updated: Dec-15-09 8:22 PM EST –
Epoxy is, say 10% stronger than the best VE and maybe a little lighter, but wildly more expensive and requires firing in an autoclave if used in thermoset/prepreg form or a production stopping postcure.
Souris R has made their peace with one of those options, but sounds a little proud of their biphenol.
On another topic above, West offers fast cure, slow cure, extra slow cure and special coated cure hardeners, so matching primary cure time to intended use should be pretty easy.
Yup
The vast majority of builders today are using VE. In the 80’s it might have been a different story.
I think some builders say "polyester"
when they are actually using vinylester.
Warren Light Craft kayaks
are built using only epoxy resin.