Considering Dacron

[greatlakes]

Gentlemen,

I just finished building my second 16' Pal and am considering removing the middle 2' section of the form to build a shorter, lighter- weight one. I'm open to any recommendations for weight reduction of the components (i.e., thinner ribs/planking, lighter wood for decks, seats and thwarts) as well as Dacron for cover. Any ideas you may have tried and worked will be much appreciated. Thank you in advance. Frank

 

[mccloud]

Since nobody has chimed in, I'll begin. You've covered about all the techniques for weight reduction that I know of, with most of them used by Old Town in the featherweight models. At Assembly 2017 the Upper Chesapeake Chapter did a demonstration on applying Dacron. The technique is quite different from canvas. We weighed the canoe before/after dacroning, with the increase only 2+ lbs., so quite a bit less than canvas. For 'filler' we used KILZ to seal the fabric, not the heavy, hard silica-containing filler used traditionally. So all told, you might save as much as 10 lbs. You can complete the process from Dacron application thru final paint much quicker, as you are not waiting for filler to harden, and there is almost no sanding involved in the dacroning technique. I suspect that Dacron/KILZ/paint is not as tough as traditional canvas/filler/paint, so would treat a canoe done this way gently. Tom McCloud

 

[Andy Hutyera]

And now for the downside. I did two Pals in Dacron and I have to say the process was fun -much different from working with canvas. The canoes looked beautiful and were indeed about 10 lbs lighter than canvas and filler. If the Canoe is going to be lightly used the Dacron should work out fine. Having used one of the canoes on several river trips where encounters with rocks were inevitable, I found the abrasion resistance was very poor. An encounter that would have scratched up a canvas job would result in a leak. Clear Gorilla tape did fix the tears but I soon grew tired of putting up with a tender hull. Both canoes have been redone with traditional canvas and fill.

I believe if you search this forum you will find posts from others who have had better success with Dacron. I believe one of the posts deals with using epoxy to toughen the bottom of the hull. I tried coating the bottom of one of my hulls with a mixture of West epoxy and fine graphite dust. This was a partial success but still not as durable as the traditional covering.

The other problem I had was the Dacron would get loose as the hull expanded and contracted with changes in moisture content. This was purely cosmetic and I could remedy it by giving the Canoe a good dunking. The baggieness would disappear in a day or so. I have never had a similar problem with canvas.

If you use Dacron you must take extra care to fair the hull to perfection. The Dacron being much thinner than canvas will show every bulge and raised tack head right through the covering.

That said, everything Tom mentioned is right on. The process is very different and much quicker because you don’t have to wait for 4 - 6 weeks for the filler to cure. You will need some specialized tools including a small iron to activate the heat sensitive adhesive and a regular iron and a thermometer to heat shrink the Dacron.

 

[greatlakes]

Thank you for your input, Tom and Andy.

This shorter/lighter canoe will see light duty on our trout ponds. The Pals will see more of the river where they've proven to take the limited abuse the river offers.

As stated, I'm in the process of figuring out where to take some weight off and, obviously, the Dacron should be the main contributor. I have some southern yellow cypress I may consider for the solo seat , decks and thwarts which is 25% lighter than cherry and white ash albeit 15% less in bending strength and 3% less stiff than Cherry. I think I can live with that.

Your points in fairing the hull to perfection is well taken and that's where a fair amount of work will happen. I may slightly thin down the ribs and planking-- perhaps by a 32nd. I plan to HVLP spray the sealant, primer and paint for a thinner coat.

Taking off two feet from the 16' Pal form may represent about 6-7 lb; going to Dacron another 10 lb (?); using Cypress perhaps another 4 lb. A single seat and fewer thwarts may take off another 3-4 lbs. I'll shoot for a 35# boat and take it as a challenge. I'm excited to take this on. Weight control of both the canoe and the paddler have become very important as the years pile on. .

Again, thank you for your insightful comments. Frank

Frank