Epoxy / Cold Weather

I am building my second Kayak. The first was a Mill Creek 16.5 in early Spring of this year. I used a plastic tent and two small heaters plugged into a cheep 120 V heating stat. mounted in utility box with a male cord cap plugged in to a 20A receptacle. It worked great.

Now I'm working on a Shearwater 17 and I am thinking about using fast cure epoxy.

Can I use it in colder temperatures? 

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RE: Epoxy / Cold Weather

You guys are talking about fast hardener, right? Fast cure epoxy is meant for mending. Normal epoxy with the fast hardener is meant for laminating. Using fast cure epoxy for laminating won't work.

Fast hardener is meant exactly for when the weather gets cold, though like all epoxies it still needs a minimum temperature above freezing or higher, depending on the brand.

For what it's worth, I find that I get uncomfortable well above the temperatures where the epoxy stops working, so the epoxy temps are not an issue - the heaters are there for me. But I'm just a cold temp wimp (raised in Southern California, never developed internal anti-freeze). Those manly Vikings from Minnesota and the other Northern Wastes probably don't need heaters for themselves.



RE: Epoxy / Cold Weather

Yes, my bad, I meant hardener, not resin.

RE: Epoxy / Cold Weather

I just received my first Kit, a Wood Duck 12.  How warm does it need to be to epoxy?  I have the standard hardener that comes with the kit.  I was considering the plastic tent method from above, but now am not sure if necessary.  I am located near Seattle.

RE: Epoxy / Cold Weather

If that's the MAS slow hardener, they say on their website that they don't recommend it for use under 65 degrees unless extended cure time is available. They recommend 7 days cure time at 77 degrees.



RE: Epoxy / Cold Weather


 I live in Seattle and if you are building in an un-heated area, then I would STRONGLY advise that you wait until it gets warmer next spring.  I absolutely shudder to think of trying to fiberglass in temps under 60.  Epoxy gets really thick and goopy in colder temperatures which makes it a nightmare to wet out 'glass or even do fill coats without using way too much epoxy.  

 I know this from experience I built my first boat on my back porch a few winters ago.  The interior looked SO bad that I dragged the boat inside my living room for the exterior epoxy work.  This was very interesting as I was building a CLC Triple and the only way to get from the front door/kitchen to the rest of the house was to crawl under the boat.  My wife and I were picking epoxy from our hair for weeks....

 Check out Hull A on my website for the gory photos...  


RE: Epoxy / Cold Weather

Forgot to mention about when, in late december I tried to epoxy the hatch lips onto the deck it took 2 weeks for the epoxy with fast hardener to cure at about 45 degrees.  Also I had major problems with all the moisture in the air.  It does rain a tiny bit in Seattle in the winter. ;)

RE: Epoxy / Cold Weather

If you're going to epoxy in cold weather, it really helps to warm up the hardener and resin first. Store the jugs in the house when you're not using them will keep them at room temperature. Placing a work light with an ordinary light bulb (e.g. 60-75 watts) close to the epoxy jugs for an hour or so before you start will warm the resin and hardener up nicely so it will have a nice, thin viscosity for wet-out and fill coats.  A string of 5 or 6 work lights (again, with ordinary lightbulbs) clamped  on a 2x4  suspended above the project will also speed up the cure time, especially if you get creative with some heavy-duty plastic sheeting to create a little tent over and around the boat (make sure that the lights  are at least a foot above the surface--otherwise it can get too hot!) In my experience, this raises the ambient temperature at the boat by about 30 degrees.

I also live in the Pacific Northwest and have successfully built boats in my unheated garage during our cool damp winters..... including a skerry whose hull got glassed around New Year's a couple years ago.  

Julie K.  


RE: Epoxy / Cold Weather

One other thought: for no spark, no fan approach.  Purely as a supplement one could load up the oven with (clean-ish) bricks, heat them up as hot as can be safely transported to the garage and then stack them into a compact pile near enough to benefit the yak and/or yourself.  A dozen bricks should help keep things warmer longer, but they probably won't do much to bring the temperature rapidly up.

 Of course if the oven is under the supervision of another person, you might want to gain prior authorization.

RE: Epoxy / Cold Weather

Thanks all.  I have some heaters for the garage, both propane and kerosene.  I was nervous about using them when doing the epoxy.  From what I can determine, the epoxy will not be a problem, just don't varnish with them.  I saw the idea of the lights on a light bar.  I actually have something like that already that I use when I have to get in the crawl space and need some light.  As soon as I get started I am sure I will have more questions. Thank you. 

RE: Epoxy / Cold Weather


The kerosene heater could be a problem even with epoxy. Epoxy doesn't like oily surface residue any better than varnish does.



RE: Epoxy / Cold Weather

I mentioned this in another thread, but here, I try to paste a (non crabby patties) link:


1200W halogen worklight on ssturdy stand for  55 bucks. The lamp I have been using uses 2 500W bulbs rather than the 4 300W bulbs in these lamps. But lots of light and heat. It's one of the big reasons I haven't been too worried about cold temperatures while working this winter.

No fumes, no vapors, no open flames, lots of light. When I am done working, I turn them off and walk away which  provides a cooling cure enviroment that helps to eliminate bubbles from outgassing. 

Pretty cheap too compared to most "heaters" that don't provide any useful light.


Ogata (eric) 

RE: Epoxy / Cold Weather


That's what I use as well. I got two work lights for $14 each at Sears.  I think mine are 750 W but they provide plenty of heat and light in a relatively small area.  They don't heat my garage so well, but pointed directly at my project they keep the materials plenty warm enough from about 3 or 4 feet away.

Tent the area and it works even better.  No ridiculous heating bills, and no worries when I leave the work for the evening.

I'm about to rip the deck off of my Northbay and do a strip deck.  While the lid's off I'm going to make a few more internal mods as well.


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