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#1
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Canoe rebuilt with Epoxy
Came across a 30-40 year old canvas and cedar canoe which maybe beyond
particle professional restoration. Any advice the option of stripping off the canvas and covering with epoxy? Would only resin be enough? Would cloth be necessary? Dino |
#2
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Canoe rebuilt with Epoxy
In article , "Dino &/or
Susan" wrote: Came across a 30-40 year old canvas and cedar canoe which maybe beyond particle professional restoration. Any advice the option of stripping off the canvas and covering with epoxy? Would only resin be enough? Would cloth be necessary? Dino I've done it both ways (re-canvas and epoxy+fiberglass); it required quite a bit more time, skill and materials to recanvas, but I believe it is The Right Thing To Do. I've always felt bad about *******izing an 18 ft Old Town square stern with the glass-plus-epoxy - I didn't really improve it any, more of a 'quick fix' really. Compared to the 16 ft 1941 Old Town HW with sponsons which I rebuilt using canvas, filler and paint- it took me longer, but I am happier with the finished result. Also, it was more pleasant working with the canvas materials than the epoxy - fiberglassing is more like auto body repair than boat building. Epoxy+glass (and YES, you WILL need the glass!) works best when the wood is completely encapsulated - not practical when the interior of the boat has a bunch of ribs. Since both boats have been used very little and are stored under cover, I can't really say which method is more durable. Too bad they don't belong to me - I'd test them out. To help you decide if you want to try recanvassing, read 'The Wood & Canvas Canoe' by Jerry Stelmok and Robin Thurlow - the last part is about restoration. Don't forget - the hull is only half the job: steam bending new ribs, replacing broken planking, rotten decks and 'wales, scraping and revarnishing the interior - these chores will likely take longer than redoing the hull exterior. My first (and last!) canvas restoration required 314 hours of my time (the sponsons added some complexity over a normal job). I spent about $600 on materials, including new decks, stems, 9 ribs, and 10 half ribs purchased from Old Town. With the same amount of time and materials I can build a VERY nice brand new cedar stripper - true it won't be an antique Old Town - but can you really say it's an antique Old Town after you've epoxied one? So my advice is: EITHER restore the Old Town using canvas, OR build a new stripper from scratch. To see a cedar strip canoe I built, you can look at the pictures on my auction at: http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3617885338 (auction ends 7/22) -- Gary Wright Springfield MO ______________________________________ |
#3
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Canoe rebuilt with Epoxy
covering with glass fibre and resin adds weight faster than strength. one method of recovering canvas is to use heat shrink dacron. Platt Monfort has an inexpensive booklet of instructions at www.gaboats.com. you'd have to replace any bad wood for strenght but you don't have to stretch the dacron or fill it like you do the canvas. I don't know about making up your own ribs as they are usually half round to save weight. (You could try the oak trim at your local home improvement store if its not full of finger joints.) -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-freenet email must have "notspam" in subject or its returned |
#4
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Canoe rebuilt with Epoxy
I have used the heat shrink Dacron to make a 14 pound canoe of Platt
Monfort's design - for that purpose it works great. It's really strong - for a 14 pound canoe. However, I don't think it's going to work out so great for an 80 pound Old Town. The heaviest Dacron I can find is 1.9 ounces/sq.yard - way lighter than the 6 ounces per yard glass you would probably use for a canoe or the 13-14 oz/yard that #10 canvas duck weighs. (Many people, myself included, use 2 layers of the 6 oz glass on a canoe bottom). Of course I'm comparing apples to oranges to grapes - these are 3 different fabrics with different properties and they are used with different coatings which may be as important as the fabric itself, but my point is: the Dacron is in a different weight class than the glass and canvas fabrics typically used for traditional canoe construction. I believe the main function of the fabric covering on a wood canvas canoe is to make the hull water proof and provide abrasion resistance and increase impact resistance. The way I waterproofed the 1.9oz Dacron was by simply varnishing it - doesn't add much weight, but it doesn't add much abrasion resistance, either, at least not to the degree that 2 layers of 6 oz glass in epoxy will, and not to the degree that #10 duck canvas properly filled with a good hard filler will. There are other coatings used on the Dacron and you could add 2 or 3 layers, but I think you would have to agree, in the context of the Old Town, using the Dacron would be experimental. Has anybody actually tried this? I'm curious to learn what you mean by: covering with glass fibre and resin adds weight faster than strength There are many kinds of 'strength' - impact resistance, tensile strength, puncture resistance, etc. I prepared test panels and dropped a 46 ounce window weight on them from various heights. The damage I saw from a 4 inch drop on a panel with epoxy, no glass, was about the same as from 16 inch drop on a panel with the same amount of epoxy, but 1 layer of 6 oz/yd glass. Judging the damage was somewhat subjective - I measured the diameter of the craters and looked for hairline cracks. I know from weighing a 14 ft canoe before and after glassing the interior that one layer of 6 oz in epoxy added 3 pounds to a canoe which weighed 48 lbs, completely finished. So it would appear that a 6.7 percent increase in weight added a 300 percent increase in impact resistance. This assumes the impact force has a linear relationship to the height of the drop - I don't know enough physics be sure this assumption is valid, but I'm guessing if it's not linear then it's MORE than linear, so my assumption is probably conservative. -- Gary Wright you can see the 48 pound canoe at: http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3617885338 ___________________________________________ In article , (William R. Watt) wrote: covering with glass fibre and resin adds weight faster than strength. one method of recovering canvas is to use heat shrink dacron. Platt Monfort has an inexpensive booklet of instructions at www.gaboats.com. you'd have to replace any bad wood for strenght but you don't have to stretch the dacron or fill it like you do the canvas. I don't know about making up your own ribs as they are usually half round to save weight. (You could try the oak trim at your local home improvement store if its not full of finger joints.) -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-freenet email must have "notspam" in subject or its returned |
#5
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Canoe rebuilt with Epoxy
"Gary Wright" ) writes: Has anybody actually tried this? yes. don't know how many but I heard last year about one shop locally that's doing it. I have no info on how durable it is. Monfort's frames are flexible. The skin has to work with the boat. The skin does not have continuous backup so is subject to puncture. I don't know how well it holds up to abraision on his boats. I imagine any abraision would be concentrated where the skin covers the stringers? On a cedar planked canoe the abraisive action would be spread out over the surface. Dacron on a cedar planked, oak ribbed canoe would just be there to keep out the water - resist moisture and resist abraision. I'd assume it would perform better than on the open framed boats. But hey, ideally a boat never touches anything but water. I'm curious to learn what you mean by: covering with glass fibre and resin adds weight faster than strength There are many kinds of 'strength' - impact resistance, tensile strength, puncture resistance, etc. in this case, the original subject of the thread, it was structural, ie. glassing over the hull (exterior only) instead of replacing cracked and broken wood. fibreglassing a heavy "plank and rib" canoe for structural strength is going to make quite a heavy boat. I haven't done the actual calculations. However if enough epoxy is put on to provide the structural strength then the cedar won't soak up water so there will be some weight savings there over the season. canvas won't provide the structural strength (rigidity) which is what the poster was looking for. the damaged wood would be replaced first before covering with canvas or dacron. I too would like to hear more from people who have used dacron. -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-freenet email must have "notspam" in subject or its returned |
#6
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Canoe rebuilt with Epoxy
On Sat, 19 Jul 2003 02:50:23 GMT, "Gary Wright"
wrote: I have used the heat shrink Dacron to make a 14 pound canoe of Platt Monfort's design -///The heaviest Dacron I can find is 1.9 ounces/sq.yard - way lighter than the 6 ounces per yard glass you would probably use for a canoe or the 13-14 oz/yard that #10 canvas duck weighs. ///using the Dacron would be experimental. Has anybody actually tried this? /// Gary Wright you can see the 48 pound canoe at: http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3617885338 Your mention of 'experimental' reminds me that 1.9 oz polyester is a standard covering these days for light aircraft. It needs special goo for gluing to ribs, and paint cover - but works well in that milieu. Brian Whatcott Altus OK |
#7
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Canoe rebuilt with Epoxy
True, but aircraft don't often encounter submerged logs or rocks.
not for any great length of time anyway. Al |
#8
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Canoe rebuilt with Epoxy
"Al" ) writes: True, but aircraft don't often encounter submerged logs or rocks. not for any great length of time anyway. for an aircraft to "encounter submerged logs or rocks" the aircraft itself would have to be at least partially submerged, indicating the possible existence of other, prior, problems with the dacron. -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-freenet email must have "notspam" in subject or its returned |
#9
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Canoe rebuilt with Epoxy
P.C. Ford ) writes: On 19 Jul 2003 23:03:06 GMT, (William R. Watt) wrote: "Al" ) writes: True, but aircraft don't often encounter submerged logs or rocks. not for any great length of time anyway. for an aircraft to "encounter submerged logs or rocks" the aircraft itself would have to be at least partially submerged, indicating the possible existence of other, prior, problems with the dacron. Are there other problems which would keep an aircraft from flying in addition to failure of the "skin" covering? I don't think we should rule out any possibilites, the pilots's own skin covering included. Makes one wonder how many thin skinned pilots and boat owners there are. They should all wear sun block to reduce the risk of skin cancer. -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-freenet email must have "notspam" in subject or its returned |
#10
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Canoe rebuilt with Epoxy
The Right Thing To Do.
Hard to argue. My first (and last!) canvas restoration required 314 hours of my time (the sponsons added some complexity over a normal job). I spent about $600 on materials, including new decks, stems, 9 ribs, and 10 half ribs purchased from Old Town. I am hoping to have a professional do it for about $600 US or $1,000 Cdn. I'd rather be paddling than puddering. To see a cedar strip canoe I built, you can look at the pictures on my auction at: http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3617885338 Nice detail!! I suspect even my profession builder will no be doing that kind of work! Regards. Dino |
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