committing to the shape of the boat, beginner questions


Hi all, and a happy new year especially to all those running in from unheated garages to thaw out fingers. It's been a mild winter so far here in Massachusetts, but I'm just not accustomed to spending a lot of time standing around outdoors, basically, trying to build kayaks.




I'm a first time builder working on a pair of 10 foot Wood Ducks from plans. It's been a fascinating process so far, and although I may have already experienced just about every mistake in the book, I've just completed the process of getting both boats fully wired up.




My hope had been to get at least this far before easing up until warmer weather, then starting with the “frankenducks (as they look with all their stitches in)” once temperatures got more hospitable for glue. However the momentum I've built up by plugging away at it day after day, a little at a time, has me pondering ways forward in spite of the outside conditions.




Being a rank novice, it's actually worked to my advantage that I've not wanted to move on to the gluing, since, building from plans, I've had a fair amount of tweaking and reshaping to get through before the boats really fit together at all. I think I dryfit and wired on the deck of one of the boats five times before it went on with anything like ease and relatively gap free.




So now that I'm ready and willing to move on past that frightening line in the builder's manual: “Now it's time to commit to the shape of your boat.” I have a question or two. I understand from MAS epoxy faq that they are comfortable with the temps down to 40 degrees for bonding, while coating is a bit higher. I've timed myself at wiring the deck on and arrived at the conclusion that as long as I can keep everything warm enough to activate properly, I'm better off doing my tacking and filleting in colder weather anyway since I'd like to have enough time to tack all my seams, fillet my ends, and wire things back up before the tacks fully set.




My questions about the tacking stage are this: should I paint my seams with unthickened epoxy before tacking them in order to keep that thirsty wood from drinking all the adhesive out of my tacks? In the manual they recommend thickening the epoxy for tacking with wood flour...wouldn't I want to use cab-o-sil, since that's what they say to use for bonding? Finally, after tacking, allowing the tacks to cure, and pulling the wires, do I need to prepare the tacks at all for the fillet which goes on top of them? I understand that in coating, if you allow the epoxy to fully cure they recommend sanding it before coating further in order for the new layer to adhere properly to the earlier it the same thing with tacks and fillets, or can I just lay my fillet atop the tacks no matter how long it's been?




Any pointers would be hugely appreciated!


12 replies:

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RE: committing to the shape of the boat, beginner questions

The "two sticks" sighting/fairing method works well. Its in the Boatbuilder's Tips section here. If you have beveled & fit the panels together well, it should have come out pretty fair. No need to  precoat the joints. The epoxy will soak in somewhat (you WANT it to), but slightly thickened epoxy wont disappear into the wood or anything. I found the supplied sryinges to be annoying-the plunger gets sticky-so I just use a paintbrush. After tacking, I was actually surprised at how strongly the panels were held together.

As far as the cold working temperatures go, I find it very effective to heat the work areas with 100 watt light bulbs in metal reflectors. I placed the lights about two feet from the boat, and saw the temperature go up from 55 degrees to 65 degrees in one hour.

No need to sand the tack welds before filleting. At the cool temps you describe, the welds won't be "fully cured" for days. Also, the fillet will be bigger than the tack welds, and have plenty of wood to grab on to.

RE: committing to the shape of the boat, beginner questions

I used wood filled for tacking, it works well. It is mixed thinner than the filet material. I think that cab makes a bettter bonding material, but this is only a short term bond. 


Where in Mas are you? I built two Ducks (10 an 12, and a 16 ft Sasafrass all from kits here in Attleboro.



RE: committing to the shape of the boat, beginner questions

Thanks Jim 777...I hadn't thought about a backup plan as far as the tack application, even though I had wondered how well the syringes work. Also, I've been experimenting with those cheap clamp lights and my thermometer and found the hundred watt bulb at about 2-3 feet seems to make a 10 degree difference, in this case 30 degrees up to 40, even with the garage door wide open. As far as my fairing went, I found the boats weren't perfect by any means but I had a hard time getting them as fair as I did, and it was starting to cause a lot of wear and tear loosening and tightening and shifting over and over. In fact, the only thing that really straightens the hull out really well is putting the deck on it!


One detail I wanted to pursue was what you said about the tacks not being cured for days and that giving me plenty of time to fillet. Does that mean I should make sure to prep the tacks somehow before going to fillet if, say, I don't have a chance to fillet before the tacks cure?


dmnolan, I see what you mean: the tacks are really just the beginnings of the fillet, and since all thats needed for now is to replace the strength of the wires in preparation for taping and glassing, a cab o sil bond must not be considered necessary. So far I've only used it for scarph joins, and keep wondering why I have so much of it.


I'm in Arlington just north of Boston, spending lots of time using google earth to explore cool places to drop the ducks! Neponset river backwaters, behind Nauset beach and Great Island in Wellfleet, the Concord seems like I could do a different day paddle every day for a year within a few hours' drive. How have you found the Ducks to be?

RE: committing to the shape of the boat, beginner questions

The Ducks are great. Plan on an extra 20 minutes for each trip to allow for oogling and questions from other Kayakers and passerbys!

Yeah there are a bunch of places to get the Ducks wet. I am looking forward to a Concord river trip. Grew up in Burlington and have canoed that river in the past. 

Good luck with the build and keep asking questions. There is a world on knowledge on the forum.



RE: committing to the shape of the boat, beginner questions

Be sure to check Laszlo's documentation of his build. Very Helpful



RE: committing to the shape of the boat, beginner questions

It sounds like your garage is fairly cold.  When you plan to coat the boat with fiberglass and epoxy please be aware that epoxy is hard to get perfectly clear at colder temperatures.  It gave us a fair bit of trouble with our boats (we were working outside).  Epoxy definately behaves best over 70 degrees.  The MAS is definately more forgiving but get as much heat as you can.  Other folks have far more expertise than myself, but that is my 2 cents.  The lamps sound like a great idea.

   - Josh

RE: committing to the shape of the boat, beginner questions

thanks again dmnolan, and how could we ever forget Laszlo, not just his good pictures but his excellent explanations! The wow factor has definitely already shown itself in my garage, and the ducks, even covered with dust and prickly with wires, have a few regular visitors among the passersby.

Josh B, my garage is more like a walk in freezer somedays, with the cement holding the cold even on warmer days. From what I've read, coating is much more problematic than filleting at low temps, so I'm trying to pace myself and focus on the tacking/filleting some time in the next few weeks, then worry about finding a decent spell for coating and glassing when it starts to get a bit warmer.

I don't know if it's ironic, but I've started to realize there's some appeal to the cooler temps as far as the process of tacking and filleting, with the time it seems to take me to wire up the decks: so I'm looking for that perfect window of temp -warm enough to activate the epoxy fully and cool enough to be able to complete the assembly without being frantically rushed!

RE: committing to the shape of the boat, beginner questions

I found that the best thing for me was a clear plastic ketchup dispenser from walmart. Only 97 cents and lasted long enough to build three kayaks. Just mix up one batch of epoxy and wood flour to the thickness of ketchup and squirt it in the seams. I used quite large tacks, just be sure not to run over the wires, makes filleting easier.

RE: committing to the shape of the boat, beginner questions

And if you do get some on the wires, 5-10 seconds of heat from a bic at the end of the will soften the epoxy around the wire and free it up nicely!


RE: committing to the shape of the boat, beginner questions

jnclark, I love the ketchup dispenser idea: people's resourcefulness when it comes to this stuff is amazing.

dmnolan, I happen to have a little soldering iron, which I was thinking of using to heat wire ends that get trapped...I've been trying to get my minds eye focused on the process of getting the wires out especially at bow and stern, where I ended up with so many so close together.


Part of me likes the idea of leaving the wires in for that steampunk look (and to save me from the trouble of taking them out of course) but somewhere I developed the suspicion that there might be situations where repairs in the field could be hindered by those little scraps of copper embedded around the ends and corners of the boat.

RE: committing to the shape of the boat, beginner questions

I forgot to mention that if you buy 2 squirt bottles, you can put a whole batch of thickened epoxy into one bottle, which will tack about half of the boat with pretty generous tacks, then use the second one to tack the rest. After about 2 hours the epoxy will be solid enough to grab with needle nose pliers and pull right out.

What I meant by not running over the wires, is that if you run over them it leaves a bump in your fillet if you don't sand them out. If your tacks aren't to messy and you feel the need to sand them, it is a pretty quick job with 150 grit. Maybe 1/2 hour.

To get the wires out of the bow-stern, clip the wires on one side as close to the wood as you can, straighten out the end left in the wood, bend the long end around, grab it with pliers, light it up with a bic lighter and start applying a gentle tug. The heat melts the epoxy and the wire puls right out. 2 WD12s, 1 WD14 and 1 17LT and we only left one wire.

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