resin choice for kayak modification

there’s a heap of material wizards out there, please edumacate me…

i’m going to reinforce the coaming on my Cadence and maybe add a keel strip before a long solo trip this spring in which i will have to beat on my poor boat mercilessly…

normally i would have used epoxy due to it’s greater strength and flexibility before cracking. however, i’ve been reading this board and all the kayak rags, (lots of you out there contributing) and there seems to be some debate as to the virtue of using epoxy resin on a boat made with cheaper resins. i was told by a composite guru at the WCSKS that my Cadence is made from the cheapest resin of all- polyester (to my chagrin) and that there’s no sense in using epoxy when working on the boat.

so what do you think: should i use a cheaper resin or would there be some benefit in applying the strip and coaming reinforcement layer with epoxy?

many thanks.

Epoxy is the best resin to use. Old power boats were always made with polyester and they are now being repaired with epoxy.


Ditto That
epoxy will stick to anything but the old polyester resin may not stick to the epoxy.

Personally, I like the two hour epoxy stuff from West Marine. Long enough to work with but not too long where things can sag if you’re not watching and/or careful with taping. Also, the coloring that is used to mix with gelcoat can also be mixed in to the epoxy (a little bit will go a long way). Also, for thickening, you can also can get some of the silica to add in. I’ve used this combination for a bunch of waveski repairs (unfortunately).


You’re adding reinforcement
You want them to be strong, right?

Makes sense to use the strong stuff.

Epoxy resin
is the way to go. I’ve done repairs,reinforcing and installed keel strips on my boats with no problems. As Sing said epoxy will adhere well to almost anything and you do want the strongest stuff. It’s more expensive but you will need so little that the cost,compared to what most of us and probably you have invested in equipment is still minimal.

As my Dad always said"If it’s worth doing,then it’s worth doing it right"


Go with epoxy
In addition to being stronger and more wear resistant, it much less noxious to work with.

epoxy it is then
thanks for clairifying for me.

To clarify something

– Last Updated: Jan-14-07 11:36 AM EST –

You have to remember, cheaper polyester resin works great for making objects because it is all made at once with one big wet mass of glass fiber and resin all curing together. Once it hardens, you have a different animal. That same resin is now totally alien to the hardened object.

Just remember when you do your repair to sand first since mold release wax stays on the kayak or canoe forever. Yes, epoxy.

Proper Protection for all resins
I would offer that subjectively epoxy is a bit more hazardous to work with than polyester resin. One can develop allergic reactions to epoxy rather quickly.

For any folks using these materials at home, I hope you’ll work outside, wear gloves and get a decent respirator with the appropriate active cartridge - especially if it becomes a regular hobby to mess with this stuff.


Seda Kayaks

i’ll don my organic respirator mask
thanks again guys for your insight.

Clarification of hazards
While SOME people may develop an allergy to UNCURED epoxy or it’s components (resin and hardener), it’s not a universal phenomenon and cured epoxy is completely inert. With any resin product, gloves and long sleeves should be worn in order to avoid contact with the skin.

The fumes from polyester and vinylester resins are noxious and toxic; that’s not true of epoxy. Still it’s not a bad idea to wear a respirator when working with it. The MEKP hardener used with the “esters” is very toxic.

Given the choice, I prefer to work with epoxy.

good stuff Brian.

If you want it to stay, Epoxy …
Prep all you want, put that keel strip on w/ polyester and there is a good chance its gonna come off in a nice long zippering strip if the boat gets flexed heavy or chunked up on rocks just right. Nice though if you want to pop it off to clean up boat prior to selling. Don’t forget you can trim things real nice with a razor blade when resin still green and save a ton of sanding. Tape everything.

Call me if you want. I have done dozens of these including Ed Gillets boats.

sanding epoxy is the culprit
>The fumes from polyester and vinylester resins are noxious and toxic; that’s not true of epoxy.

True, laminating is quite harmless, but what many overlook is that often the cause for developing an allergy is sanding epoxy when not fully cured – which can take a month and with temperatures below 20 degrees Celsius (68F) much longer.

Sanding epoxy can best be done outside in the wind.