Initial epoxy coat.

[Danny Turner]

I`m building 16ft Abenaki, plans from Newfound Woodworks.This is my first effort.I`m following Ted Moores Canoecraft for instruction.Yet he doesn`t say anything about applying an initial coat of resin to the hull before applying the fibreglass unlike some other builders who say that this is a must. Can anyone say if this is essential or not?
Great to see so many people from all over the world shareing a love for wood strip "boats".

[Glen Smith]

Hi Danny. Boy, you are going to open a whole can of worms with a question like that. Some builders are downright against it and some wouldn't build without precoating. You can read one builder's opinion on John Michne's website: http://www.michneboat.com click on "My Website", "Builder's Corner", "Fiberglassing 101".

The results of precoating or not will, in part, depend on the weight of the fiberglass cloth you use and the viscosity of the epoxy you use. I have tried the precoating using 6oz cloth and a fairly thin epoxy (local brand) and I liked the results better than without the precoating. I obtained a more even wetout of the cloth since the wood couldn't absorb any of the epoxy applied during this stage. The only drawback I can see is the fact that precoating adds one day to your project for each surface that you precoat. My results and preferences do not necessarily represent those of other builders so don't be surprised if you read some conflicting opinions on this matter.

[mtpocket]

What you are referring to is the precoat. Some builders skip this step and go on to the wetout coat. I did a precoat on my Redbird and am glad I did. Somewhere I read about how it seals the wood and prevents bubbles from appearing under the fiberglass during the wetout coat. If this is true or not, I don't know but I had no bubbles using this method. What I found to be true is that during the wetout coat, the wood was not soaking up all the resin and starving the cloth of the resin needed to fully saturate the cloth. Other builders can weigh in on this and give you their opinions. Like I said, some do it and some don't.

[Bassbug]

My brother-in-law and I built and Redbird last year (my first canoe and first experience with fiberglassing) and I am currently working on a kayak. I precoated these projects. By sealing the wood, it was just one less thing I had to worry about and one less worry was a blessingl. As I gain experience, I can now glass without the precoat and it all works out. Precoating isn't essential, but for me it made glassing much easier. The extra step and time was worth it for me. Good luck on your Abenaki - this forum is a great place with lots of good answers to questions.

[Juneaudave]

My two bits...definately not essential for a single layer of 6 oz or less cloth. I have precoated on double layers, just to minimize the amount of epoxy I had to use on wet out, and for overlapping layers to assure uniformity between the layers....Good question though...Juneaudave

[Fred G]

I like to precoat. I do my filling after the precoat and know my fills will color match nicely.

[Patricks Dad]

When we built our Redbird, we did not pre-coat. We were careful to ensure that we didn't have any glass starvation and everything worked out just fine.

The thinking that drove us to not precoat was the fact that we were trying to do the whole job in one long day. Pre-coating would have required either that we start earlier in the day (we started at 7AM the way it was) to do the precoat or do the pre-coat the day before and sand before starting the glassing.

I was worried about getting an even sand on the pre-coat (assuming that if you sanded through the epoxy in patches, you would get epoxy abosrption where we didn't expect it and would end up with a blotchy finish).

Doing the pre-coat a few hours befor starting with the fiberglass would require waiting long enough to ensure that the epoxy was set enough to ensure it wasn't sticky for laying on the glass yet not too cured to avoid sanding. This seemed to tricky for us and we simply opted to pay close attention to the glassing job when we went ahead without a pre-coat. We finished our 4th coat around 1AM the next morning (I'm pretty sure I didn't have enough energy for another round).

I would guess that the worry about sanding evenly is probably unwarranted and could have worked out just fine.

Note: we used West System 105/207.


Either way will work even though some swear by it and some swear at it.

[reinbilt]

Danny,
Randy makes a good point. When sanding the precoat it can be difficult to obtain an even result. One area might get sanded a little more than another and you'll end up with a blotchy effect. I precoated my first two boats and that happened. My next two no precoat and no blotchy effect. Like Randy timing the the curing of the epoxy to avoid sanding seemed too tricky for me.

[KARKAUAI]

I've precoated both of my canoes, using MAS slo epoxy. Plenty of window to time it so you don't have to sand. It does require ~ 8-10 hours to let the first coat cure enough to allow laying the glass on without sticking (at 70F), so I did the precoat on Fri evening, scraped the few drips before going to bed. Next morning I did the wet-out and that evening I did the first fill coat. On Sunday I did two more precoats and was done with all glassing and epoxy in one weekend even with slow curing epoxy.