Anybody ever use non-standard canvas thicknesses?

Howie

Howie

Wooden Canoe Maniac
I have a fella who's really excited about a 13ft Tremblay I just picked up because it weighed just 50#. One of the reasons it was so light was because it was covered in Verolite (PVC-impregnated canvas). I've done enough research to see that not too many people have a good opinion of Verolite, so I'm looking for other ways to lighten the canoe.

I was told by John at Housatonic Canoe Shop that he's looking into using a 7 oz/sq-yd canvas. I'm wondering if anybody else has used this stuff?

I think most of us use the #12 Duck (thinner), #10 Duck (most popular), or #12 Duck (thickest) for covering our canoes. These are the canvasses you can get from Northwoods Canoes. I myself have almost always used #12 Duck. But there are other sizes of canvass available. Different sizes equate to different thickness. So I'm thinking the thinner the canvas thickness, the less mud/filler is absorbed, so the lighter the mudded canvas weight will be. Of course, a thinner canvas is less resistant to wear & tear.

I've just ordered a sample of canvas from Big Duck. There's:
7 oz/sq-yd Single Fill Canvas (about 0.022" thick)
10 oz/sq-yd Single Fill Canvas (about 0.026" thick)
12 oz/sq-yd Single Fill Canvas (about 0.030" thick)
#12/11.5 oz/sq-yd Double Fill Duck (about 0.027" thick)
#10/15 oz/sq-yd Double Fill Duck (about 0.032" thick)
#8/18 oz/sq-yd Double Fill Duck (about 0.037" thick)

I'm guessing that a 7oz vs #12 Duck filled canvas would be about 30% less weight in the canvas itself and maybe 20% less in mud weight.

I'm wondering if anybody else has used this 7 oz canvas?
 
I have some 7oz single fill from Jerry’s artarama. Not really the same stuff at all. Single fill you can see through the weave and not very substantial. I’d worry that the filler would just squeeze through, it’s like a curtain fabric. Double fill #12 in contrast is thick and substatial, no filler will squeeze through.

Maybe a high thread count bed sheet material would be better - like from the discussions about Egyptian cotton. Hard to find something long enough though.
 
Floydvoid: Never used Dacron. Guess I ought to read up on it. Just downloaded the Stits manual mentioned in these threads somewhere.
 
Tom MacKenzie built some of the most elegant small canoes. They were lightweight and the finishes were always gorgeous, at least on the ones I've seen.
Tom used Ceconite on his hulls.
As far as I know, it held up well enough. All of the "Bugs" I've seen were in good original condition.
You should probably take a look into Ceconite.
Mike
 
Howie,

I used ceconite on my Chestnut Chum following the written instructions that Tom MacKenzie worked up.
I did find some clarity issues with Tom's instructions but managed to work thru them with good results.
The ceconite is a heat schrink covering and must be filled with Cecofil. Bill Clements was intrigued, not being familiar with the use of ceconite instead of canvas and came to my shop the day I applied it and heat schrunk it. It is an expensive alternative to light weight canvas but the weight reduction is incredible. My 15' Chum weighs 51 pounds. I did encounter some buckling of the ceconite under the outwales after the canoe had been stored inside & the cedar dried out. Rehydrating the cedar satisfactorily solved that issue once the canoe was put back into use.

Ed
 
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Ed: Thanks for the info. Could you send me the instructions from Tom MacKanzie? Well... since they're written maybe it'd be easier to take a pic of each page. You could send them to hjehan@rochester.rr.com or post them here.

But I'm dying to know... Do you stretch the Ceconite like a canvas, staple the top edges to the rail area, and staple at the stems? Do you cement the ends together at the stems? What special gear would I have to buy? How does the final covering handle the change in weather - Does it wrinkle as the canoe expands & contracts?

Ceconite is a woven fabric, right? Why does it have to be filled with Cecofil?

So many questions...
 
Howie,
When I return from pheasant hunting this afternoon and I am not too pooped, I will go to my files in the shop and search for Tom's ceconite instructions. I am sure that I saved them (I save everything).

To answer some of your questions:

You do not stretch ceconite fabric - just lay it on , secure the sides and ends ( this is where Tom's instructions are lacking and if I do another I will diverge from them) and then with a heat gun, heat shrink it tight.

I will have to read the instructions before I answer how ends were fastened. I did this at least 10 years ago.

There is a glue for the ceconite that you need to buy, plus cecofil. You probably already have a heat gun but you must do a heat sink temperature test with it as the heat shrink process does require a specific temperature. I will provide the sources for the material.

Heat shrink dacron is what is used on fabric aircraft so it is an exceedingly strong fabric. I have used my chum for many years fly fishing remote brook trout ponds and it has held up well. I applied amber shellac to the hull from the water line down applying that over the unpainted cecofilled fabric in the same manner as I have done with canvas covered canoes that I have restored.

As I mentioned, I did get wrinkles under the outwales when the chum was hung in the shop and the cedar
dried out. The shop gets really warm in the winter with the wood stove going ! I think that this can be minimized by doing a different fabric fastening along the gunnel than what Tom outlined in his instructions. Tom said to use double sticky tape and not staples to hold the fabric in place while you heat shrink. I have a different idea that I will share when I provide you with Tom's instructions.
 
Ceconite is a fabric used for covering aircraft wings. Stewart Systems sells a non-certified Ceconite that is probably just fine for canoes. 7 yards is $90. I’m not sure how it stretches, but I think it is heat shrink.
Ekofil is the filler for it. The Cecofil name went by the wayside a long time ago.
 
It's my understanding that a heat gun is not necessarily the best thing to use to shrink the material. The temperature cannot be controlled precisely enough. 250 degrees is the magic number to shrink consistently. An electric iron is suggested. Presumably the hull will need to be very perfectly fared to achieve good results.
The laps at the stems will be bonded using EkoBond. The 104 Ceconite (102 seems like overkill) is filled with Ekofill.

This all sounds pretty interesting. The material sounds like it is as tough as nails.

More than anyone needs to know is here:
 
It's Howie's fault.
When he figures out how much this is going to cost he'll forget about the extra weight.:p
 
Howie-
I just emailed you two sets of Dacron instructions:
1) Dacron - A Canvas Alternative by Alex Combs of Stewart River Boatworks
2) Applying Dacron to a Canoe - Demonstration by the Upper Chesapeake Chapter at WCHA Assembly, 12 July 2017
Hope this helps!
-Worth
 
Whoever wrote the WCHA instructions did a really great job. There is only one point that is not entirely clear to me related to centering and then adjusting the cloth on a diagonal. I'll need to re-read that to be sure I understand the exact intent.
Otherwise, these instructions should be more than enough to accomplish a recanvassing.
I'm thinking I need to try this on an upcoming project.
 
MGC said:
There is only one point that is not entirely clear to me related to centering and then adjusting the cloth on a diagonal.
Click to expand...

I suspect that this is a trick which Joe Lavoie used to canvas short and fat boats like the small fifty pound models and dinghies. The idea is to pull on the bias instead of directly against the thread of the fabric. A normal envelope to canvas a canoe right side up has the top edges even. The sheet of paper shown below is folded on a diagional to help show this. It gives fabrics a bit more stretch which can make things easier.

Benson



IMG_5537.jpg
 
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Howie,

I have located the "Ceconite Instructions" in my files that Tom Mckenzie sent to me.
Also in the file was "Procedure Manual # 101" which was provided by Aircraft Spruce & Specialty Co. from whom I purchased the ceconite 101 fabric and 1 quart of ekofil in 2010.
I also have the article "Dacron - A Canvas Alternative" by Alex Comb.
You can see if you can secure a copy of "Ceconite - Shrinking the Fabric" by Ron Alexander _email addy -www.randolph aircraft.com. Ron's writings ( several topics) covers use of ceconite on aircraft using nitrate and butyrate dope.

Provide your email addy & I will send you Tom's instructions.

You can also use Ekofil filler ,latex and lightweight sparkling compound mixture on # 10 canvas with a significant weight savings over traditional weave fillers. Mike Cavanaugh and Dan Miller experimented with this . You can locate their writeup by doing a search in the WCHA forum.

Ed
 
Worth Gretter said:
1) Dacron - A Canvas Alternative by Alex Combs of Stewart River Boatworks
Click to expand...

I don't mean to link away from this forum, but the following very long post discusses and has photos of Alex Comb's method of applying Dacron (Ceconite). The thread itself is more concerned with coating the bottom of wood canoes with an epoxy/graphite mixture.

Epoxy w/ Graphite Powder on Bottom of Wood Canoe + How a Wood/Dacron Canoe is Made

Some builders of rib and plank canoes, especially those that use Dacron instead of canvas, paint the bottom below the waterline with a mixture of epoxy and graphite powder instead of the usual marine paint on the rest of the hull. The supposed advantage of this treatment is that the...
www.canoetripping.net
 
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