Canoe rebuilt with Epoxy

In article <H7nRa.7909$jL2.969691@ursa-nb00s0.nbnet.nb.ca> , "Dino &/or
Susan" <kubik.RemoveThis@nbnet.nb.ca> 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 bastardizing 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:
<a style='text-decoration: underline;' href="http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3617885338" target="_blank">http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3617885338</a>

(auction ends 7/22)
--
Gary Wright
Springfield MO
garydeanwright.RemoveThis@mchsi.com
______________________________________<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 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.)

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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:
<a style='text-decoration: underline;' href="http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3617885338" target="_blank">http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3617885338</a>
___________________________________________


In article <bf8n3u$nst$1@freenet9.carleton.ca> , ag384.DeleteThis@FreeNet.Carleton.CA
(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
<font color=purple> > Monfort has an inexpensive booklet of instructions at <a style='text-decoration: underline;' href="http://www.gaboats.com.</font" target="_blank">www.gaboats.com.</font</a>>
 > 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
<font color=purple> > homepage: <a style='text-decoration: underline;' href="http://www.ncf.ca/~ag384/top.htm</font" target="_blank">www.ncf.ca/~ag384/top.htm</font</a>>
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 >> Stay informed about: Canoe rebuilt with Epoxy 

"Gary Wright" (garydeanwright@mchsi.com) 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.



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On Sat, 19 Jul 2003 02:50:23 GMT, "Gary Wright"
<garydeanwright DeleteThis @mchsi.com> 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?ViewItem&item=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<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Canoe rebuilt with Epoxy 

Brian Whatcott wrote:

 >
 > 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.

True, but aircraft don't often encounter submerged logs or rocks.

--
Regards

Brian<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Canoe rebuilt with Epoxy 

 > True, but aircraft don't often encounter submerged logs or rocks.

not for any great length of time anyway.

Al<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Canoe rebuilt with Epoxy 

On 19 Jul 2003 23:03:06 GMT, ag384.TakeThisOut@FreeNet.Carleton.CA (William R.
Watt) wrote:

 >
 >"Al" (Almann@mygaff.fsnet.co.ukdontspamme) 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?<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Canoe rebuilt with Epoxy 

"Al" (Almann@mygaff.fsnet.co.ukdontspamme) 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.

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P.C. Ford (cwservices2@qwest.net) writes:
 > On 19 Jul 2003 23:03:06 GMT, ag384.DeleteThis@FreeNet.Carleton.CA (William R.
 > Watt) wrote:
 >
  >>
  >>"Al" (Almann@mygaff.fsnet.co.ukdontspamme) 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.

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ag384.DeleteThis@FreeNet.Carleton.CA (William R. Watt) wrote in message news:<bfe909$2ko$1@freenet9.carleton.ca>...
 > P.C. Ford (cwservices2@qwest.net) writes:
  > > On 19 Jul 2003 23:03:06 GMT, ag384.DeleteThis@FreeNet.Carleton.CA (William R.
  > > Watt) wrote:
  > >
   > >>
   > >>"Al" (Almann@mygaff.fsnet.co.ukdontspamme) 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.

Hummm, William. I have no problems with you saving money by using
polyester, but you should break down and buy a good mask, seems the
fumes are getting to you
Scotty<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 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:
<font color=purple> > <a style='text-decoration: underline;' href="http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3617885338</font" target="_blank">http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3617885338</font</a>>

Nice detail!! I suspect even my profession builder will no be doing that
kind of work!


Regards.

Dino<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Canoe rebuilt with Epoxy 

Dino,

 > I am hoping to have a professional do it for about $600 US or $1,000 Cdn.
Yeah, I thought that sounded about right, too, BEFORE I did the job. I
charged $1000(US), minus $600 for materials, divided by 314 hours - I made
$1.27 per hour on that job. Hope your 'professional' doesn't see this.

 > I'd rather be paddling than puddering.
That's why it was my last restoration.

<font color=green>  >> <a style='text-decoration: underline;' href="http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3617885338</font" target="_blank">http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3617885338</font</a>>
 >
 > Nice detail!! I suspect even my profession builder will no be doing that
 > kind of work!

It's interesting that in modern useage 'professional' craftsmanship is
generally considered to be superior to 'amature' - yet only amatures can
afford to put the time into a project that results in wages of $1.27 per
hour. I am astounded to pay $40-60-80 per hour shop rates to have a
'professional' repair my lawn mower, plumbing, or automobile. I wonder what
professional boat builders, who have equivalent skills and similar
investment in tools make?

If I had charged $40 per hour to restore the Old Town, the bottom line would
have been $13,160 (including materials at cost - most places add some profit
margins to their parts). I guess I should think about going pro.

--
Gary Wright
Springfield, MO
_________________________________

In article <qk_Sa.11376$jL2.1237755@ursa-nb00s0.nbnet.nb.ca> , "Dino &/or
Susan" <kubik DeleteThis @nbnet.nb.ca> wrote:

  >> 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:
<font color=green>  >> <a style='text-decoration: underline;' href="http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3617885338</font" target="_blank">http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3617885338</font</a>>
 >
 > Nice detail!! I suspect even my profession builder will no be doing that
 > kind of work!
 >
 >
 > Regards.
 >
 > Dino<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Canoe rebuilt with Epoxy