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Permalink Reply by Greg Hatten on December 28, 2008 at 8:45am

Jason - I had the same "cold weather" concerns along with "moisture" concerns as I applied the epoxy and assembled the boat. I put a big thermometer in the garage and used a space heater to help get the temp up to +50... I couldn't keep the temperature "constant" enough for my "preference" and I blame that on the "cloudiness" I was getting on my first attempts at epoxy. (I think it was also a lot of "inexperience" working against me... I had never worked with epoxy before and there was a lot of trial and error)....
After a couple of false starts and a lot of stripping and sanding - I finally waited until a weekend when my wife was out of town and moved my side panels indoors to a "constant" 70 degrees. She came back to an "expanded" boat shop and wasn't too pleased that I shut down the entry way of the house for a week while I applied several coats of epoxy and varnish to the sides. It produced some pretty good results and she was a good sport about it!!
That probably doesn't help you much, but that's how I solved it...
Greg

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Permalink Reply by Jason Knight on December 28, 2008 at 8:53am

Greg,
I am feeling like since this is also my first attempt at applying epoxy to large areas I don't want to decrease my odds of success with inconsistent temperatures. I am going to read up in the epoxy spec sheets to see what they recommend as well before I start (just have to find the sheets! - good luck! haha)

Maybe I will do a couple setups with the temperature and see if I can maintain a good temp before I try.
What kind of space heater were you using? Electric?

Thanks!
-jk-

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Permalink Reply by Greg Hatten on December 28, 2008 at 9:06am

Jason - I used a couple of small electric space heaters - just couldn't do the job. My suggestions for working in Epoxy are to work with small controllable batches, apply thin coats, and exercise patience with the process. If you are using the West System epoxy - I met those guys at the Port Townsend Boat Festival & they were VERY helpful, nice guys. They're located in Bay City Michigan - one guy in particular was fascinated with the whole "Drift Boat" thing - his name is Alan Gurski - he's Executive Vice President and can be reached at arg@gougeon.com. He suggested I might have had better luck with their #107 instead of the #105 that I used. It all worked out - got the finish I wanted and have a pretty good "boat building" story to tell.
GH

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Permalink Reply by Mike Baker on December 28, 2008 at 10:40am

Hey Jason,
I am assuming you have not started assemblying the hull yet. The common practice is to epoxy the sides prior to assembly, but I prefer to do it after assembly. This allows me to cover the nails and/or screws with epoxy then varnish making a cool look (like a strip canoe). This would get you building now then later you can do the finish. I am of course talking about the outside if you are epoxying the inside that has to be done prior to assembly.
I build in the cold all the time, system three silvertip with the fast hardener allows cure down to 35. I seldom get my shop above 50 and this stuff cures enough in one day for sanding. One of the keys is to heat the resin & hardener prior to mixing. I simply put the jugs in front of a cheap electric heater with a fan until it has a thin enough consistancy. I also mix very small batches about 8 oz.
One other thing, I don't like propane for heating when I am doing epoxy it makes the humidity in the shop very high this can lead to some cloudiness.
Hope this helps.
Mike

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Permalink Reply by Jason Knight on December 28, 2008 at 10:46am

I will assume those kerosene torpedo heaters are going to create humidity as well?
My original plan was to use a torpedo heater to get the temp up - then crank some electric space heaters to maintain while working. Think that would work?

It might actually be good for me to build then do the exterior finish after the hull is built...
I had not really considered that as an option. Thanks for the pointer.

I am using System 3 epoxy.

Thanks!
-jk-

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Permalink Reply by lhedrick on December 28, 2008 at 4:37pm

Jason,

If epoxy is mixed and placed in a cold place it will not cure. If your shop temperature drops below the working range of your epoxy and hardeners, it will just sit there in a sticky state until it gets warm. There will be no problem with the cure it will just take longer.

This can actually be an advantage. You can lengthen the re-coat window so no sanding will be required. When the epoxy is no longer tacky just cut back the heat and it will shutdown the curing process. Then you can warm up the shop and re-coat 2 or 3 days later and skip the sanding part.

One thing to remember is that if thicker coats can't cure they can slowly run if they are are vertical surfaces so, just keep the shop warm long enough for it to cure enough so it can't sag. Thicker coats are not a good idea in any case. I see no reason to leave the heat on any longer the a few hours after you are done working. Just cut the heat back after about 5 - 8 hours.

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Permalink Reply by Randy Dersham on December 28, 2008 at 5:59pm

This is all great stuff Jason. The Systems Three is a great penetrating epoxy but it doesn't like to be below sixty degrees. I also recommend that the first coat is allowed to soak into the plywood.

You can apply the first coat with a scraper or edge of a board, allow the epoxy to soak in, then lightly scrape away any excess that doesn't soak. This will bond the fibers of the plywood and give you a very even surface. Allowing the epoxy to soak in and not pool will eliminate any worries about clouding while it is cold. It also allows you to protect the side panels during construction yet still get the epoxy over nails look that Mike was talking about when you do another light coat after you have the boat built.

You do give up a little bit of epoxy soaking in and around fasteners that is a slight advantage to Mike's method.

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Permalink Reply by AJ DeRosa on December 28, 2008 at 6:07pm

Jason,
Good advice from all these posts. We do a lot of cold weather work here in Jackson Hole. Our shop is at 50 degrees max and much colder over night. A few tricks that we use might be helpful. We keep our epoxy in a warm box. An old fridge with a light bulb for heat works great but we have used cardboard or wooden boxes as well. Put a thermometer in there and keep it at around 70. If we are doing a panel we will warm the wood by tenting with a tarp with a small electric space heater under the piece The warm epoxy flows nicely on the warmed wood. Now that the tent is off the whole thing will cool a bit, drawing the epoxy into the wood, the opposite effect of outgassing. Using a fast hardener we get a partial cure overnight that allows another coat the next day without sanding. We go back to the tenting of the piece to get a final full cure when we want it. Remember the shop doesn't need to be above 50 just the piece you are working on. You can get quite creative with your tent building to deliver heat when and where you need it without having to heat the entire work space.

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Permalink Reply by Jason Knight on December 29, 2008 at 5:26am

Wow thanks so much for all the information guys!
I am feeling much more confident in tackling this part of the build knowing how you guys have done it, and worked around cold temperatures. I think I will do a single coat on the exterior panels, build the hull, then apply the second coat after it is assembled to get epoxy over nails look we were discussing. I will not worry about the bottom panel until I am ready to install it. That piece is getting a layer of fiberglass (which is another topic I will be inquiring about when the time comes).

I am almost decided that the interior will be finished in oil...
So I can just worry about the exterior panels getting that coat of epoxy before construction.
I do not have to coat any of the interior parts with epoxy if I am going with the oil finish right?

Thanks again for the help!
-jk-

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