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Replacing gunnel on my canoe (slightly OT)
I have a 10' canoe. The gunnels are a pair of 3/4"x5/8" pieces of what
looks like spruce. (one pair on either side) One piece has about 2' rotted away. We are still using the canoe, but it can't be a good idea. Replacing the entire gunnel would be difficult, both because of the way the canoe is build and my inability to cut a 10' strip of wood. So, I would like to replace the rotten part, plus some good wood on either size, for a total of 4'. I cut 2 5/16"x3/4" pieces of cherry 4' long. (somewhere I read that cherry is rot resistance, plus I happened to have a suitable scrap of cherry). I can easily bend the strip to the required size. So, what I plan is to install one 5/16" piece to the canoe by screwing it to the other half of the gunnel. Then I will glue the second 5/16" piece to the first, holding it in place with screws and some clamps. 1) Does this make any sense? Will the cherry strips ever relax, or will they always be under tension? 2) Is Titebond2 adequate, or should I use epoxy? Oddly, one 5/16" strip is much more flexible that the other, eventhough they came from the same 3/4" piece of wood and look identical. |
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Replacing gunnel on my canoe (slightly OT)
"toller" wrote in
: I have a 10' canoe. The gunnels are a pair of 3/4"x5/8" pieces of what looks like spruce. (one pair on either side) One piece has about 2' rotted away. We are still using the canoe, but it can't be a good idea. Replacing the entire gunnel would be difficult, both because of the way the canoe is build and my inability to cut a 10' strip of wood. So, I would like to replace the rotten part, plus some good wood on either size, for a total of 4'. I cut 2 5/16"x3/4" pieces of cherry 4' long. (somewhere I read that cherry is rot resistance, plus I happened to have a suitable scrap of cherry). I can easily bend the strip to the required size. So, what I plan is to install one 5/16" piece to the canoe by screwing it to the other half of the gunnel. Then I will glue the second 5/16" piece to the first, holding it in place with screws and some clamps. 1) Does this make any sense? Will the cherry strips ever relax, or will they always be under tension? 2) Is Titebond2 adequate, or should I use epoxy? Oddly, one 5/16" strip is much more flexible that the other, eventhough they came from the same 3/4" piece of wood and look identical. 1) Cherry heartwood is supposed to be rot-resistant, strong, and flexible. You could also find some spruce, Douglas fir, Eastern White cedar (Western Red cedar is too soft), hactmatack, black locust, etc. Make sure the grain is very straight. 2) Building up a laminated gunwale should work just fine, but you should cut strips thin enough to bend easily, since you won't be steaming them to make them more flexible. 3) If you just cut the rotten pieces out with 90-degree cuts the gunwale will develop "hard spots", or kinks, in the sweeping curve of the gunwale, right at the places you cut. You need to cut scarfs, or sloping ramp-like cuts, at each end of the gunwale piece you are removing. Ideally the scarf will have a 12:1 ratio, i.e., the "ramps" will be 7-1/2 inches long, assuming the gunwale is 5/8 inches deep. You could probably get away with 8:1, or 5-inch-long scarfs. 4) Epoxy would be best, but since the gunwales won't be continuously immersed in water (right?), Titebond II should work alright, if you believe the bottle. 5) Be sure you clamp the scarfs well so that they are tight right up to the thin ends. You might even want to make the repair just a little fat and smooth it down to match the existing gunwale. 6) Be sure to dry-clamp everything before you apply glue, just to make sure it's going to work out well. If clamping distorts the gunwale, you could fashion a thick caul, or backing plate, which matches the curve of the gunwale, and clamp it on the side opposite the repair. This should keep the gunwale from distorting while clamping. -- John Snow "If I knew what I was doing, I wouldn't be here" |
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Replacing gunnel on my canoe (slightly OT)
"toller" wrote in
: I cut 2 5/16"x3/4" pieces of cherry 4' long. (somewhere I read that cherry is rot resistance, plus I happened to have a suitable scrap of cherry). I can easily bend the strip to the required size. So, what I plan is to install one 5/16" piece to the canoe by screwing it to the other half of the gunnel. Then I will glue the second 5/16" piece to the first, holding it in place with screws and some clamps. 1) Does this make any sense? Will the cherry strips ever relax, or will they always be under tension? 2) Is Titebond2 adequate, or should I use epoxy? This sounds reasonable to me. I would suggest you scarf it into the existing wood, rather than making a butt joint (i.e. cut the existing wood to a taper using a chisel, and cut a mating taper on the ends of the new piece). Epoxy would be a better choice for the glue. I don't know that cherry is remarkably rot-resistant - you might want to paint the whole of it with epoxy to seal it. John |
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Replacing gunnel on my canoe (slightly OT)
Get a piece of air dried Oak or Cedar or whatever the canoe builder used.
Cut it to size and soak it under water for a couple of days. It will bend in like a dream. I would not use cherry since it is not rot resistant, no matter what the books say. Let it dry in place (clamped) for a week or so. You will then be able to epoxy it in place. Epoxy is waterproof, that other stuff is not! I have had tightbond fail on boat projects where it should have held. The business about scarf is exactly correct. An easy way to make the scarf on the boat piece is with a flexible disk sander using coarse grit. These can be rented at most tool rental places. Once that piece is scarfed, trace the angle to the new piece and grind away. Good luck! The actual labor should be a couple of hours. If you cannot get airdried wood in your area, let me know, we have plenty of it here in Maine. Dave |
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Replacing gunnel on my canoe (slightly OT)
"toller" wrote in message ...
I have a 10' canoe. The gunnels are a pair of 3/4"x5/8" pieces of what looks like spruce. (one pair on either side) One piece has about 2' rotted away. We are still using the canoe, but it can't be a good idea. Replacing the entire gunnel would be difficult, both because of the way the canoe is build and my inability to cut a 10' strip of wood. So, I would like to replace the rotten part, plus some good wood on either size, for a total of 4'. I cut 2 5/16"x3/4" pieces of cherry 4' long. (somewhere I read that cherry is rot resistance, plus I happened to have a suitable scrap of cherry). I think you misread, misremembered, or your source was wrong. But the good news is if you finish the wood well it won't rot. At least it'll look cool Epoxy is the preferred glue for boats. It is also frequently used as a finish to encapsulate the wood to prevent rot. The fancy way to splice in a repair like that is with a scarf joint. the simple way is to butt the ends of the repair with the existing wood and then overlap the butt joint with a short piece underneath or behind it. There are lots of good websites that deal with wooden boat and canoe building and also a rec.boats.building newsgroup where I'm sure you can get good information. -- FF |
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Replacing gunnel on my canoe (slightly OT)
toller wrote:
I have a 10' canoe. The gunnels are a pair of 3/4"x5/8" pieces of what looks like spruce. (one pair on either side) One piece has about 2' rotted away. We are still using the canoe, but it can't be a good idea. Replacing the entire gunnel would be difficult, both because of the way the canoe is build and my inability to cut a 10' strip of wood. So, I would like to replace the rotten part, plus some good wood on either size, for a total of 4'. I cut 2 5/16"x3/4" pieces of cherry 4' long. (somewhere I read that cherry is rot resistance, plus I happened to have a suitable scrap of cherry). In the future, you might want to check http://www2.fpl.fs.fed.us/. They say that cherry is indeed "very resistant to heartwood decay"--I did not know that. I can easily bend the strip to the required size. So, what I plan is to install one 5/16" piece to the canoe by screwing it to the other half of the gunnel. Then I will glue the second 5/16" piece to the first, holding it in place with screws and some clamps. 1) Does this make any sense? Will the cherry strips ever relax, or will they always be under tension? They'll relax to some extent, but there will always be some stress unless you pre-bend them. Kind of like an overloaded bookshelf--it will sag and take a set but when you take the books off it will still spring back some. I presume you know to use a long scarf joint between the new pieces and the old. 2) Is Titebond2 adequate, or should I use epoxy? On a canoe, I'd use resorcinol myself, but epoxy should be fine. I wouldn't trust _any_ PVA glue on a stressed part of any boat. Having your glue let go at sea can ruin your whole day (apologies to Thucydides). Oddly, one 5/16" strip is much more flexible that the other, eventhough they came from the same 3/4" piece of wood and look identical. Wood is strange that way--properties are not always uniform. Just make sure it's all heartwood if you're looking for decay resistance. -- --John Reply to jclarke at ae tee tee global dot net (was jclarke at eye bee em dot net) |
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Replacing gunnel on my canoe (slightly OT)
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Replacing gunnel on my canoe (slightly OT)
J T wrote:
Thu, Jul 15, 2004, 11:48pm lid (J.*Clarke) says: snip On a canoe, I'd use resorcinol myself, but epoxy should be fine. I wouldn't trust _any_ PVA glue on a stressed part of any boat. Having your glue let go at sea can ruin your whole day snip OK, I'll bite. Why would you imply that a PVA glue would "let go at sea" on a canoe, stressed part or not? Because having spent a fair part of my life out of sight of land I have a great respect for the ability of the sea, lake, river, stream, or pond to damage anything that is floating on it. It is a truism that the sea can kill any ship and the wise sailor gives it as little help in that endeavor as he can. Ever chip through the rust on a warship, built from the finest steel in the world, and covered with high-quality marine enamel from the time that it was first built (the Navy will spend for good paint because they don't like to have their ships turn to rust) 90 feet above the waterline where a landlubber would assume that it never gets exposed to salt water, and find after chipping through an inch and a half of rust that there wasn't anything there but rust? First time you do that you lose all faith in the notion that distance above the waterline and protective coatings guarantee that the material will never be wet. tt's not going to be submerged, at least not in normal use. It's when things get abnormal that people die. In any case, the particular part that he was replacing was rotted out. That means that it was kept wet for a fair amount of time. And, it's not like wood glue has never been used in boatbuilding before. Resorcinol glue _is_ "wood glue". It's just truly waterproof wood glue. I'd imagine it'll wind up with a varnish, or other protective coating too, which will keep moisture away from the glue. Now you see, there I have the advantage of you because I have learned in the real world that (a) paint, varnish, etc, canot be counted on to keep the underlying surface dry when it is covered by standing water and (b) even the very expensive multipart coatings have a limited service life in a marine environment. If the "varnish or other protective coating" will keep moisture away from the glue" then why did the wood rot out in the first place? Or will it just magically keep moisture away from the glue and not from the surrounding wood? Do you know of a stressed PVA glue joint that "let go at sea"? I don't know anyone who was stupid enough to use PVA glue in a stressed joint on a boat. However I do remember a laminated tiller, nicely carved by a local artisan and glued together with what he assured us was "waterproof glue", lying on the sole of the cockpit completely delaminated. And that tiller was under no stress to speak of and was subject to less water exposure than a canoe gunwale when it came apart. Look, if you want to stick your neck out that's fine, but when you start advising other people to do dangerous things while pretending they are not dangerous you're behaving irresponsibly. Grok the concept--bad advice about how to use a table saw may cost somebody a finger. Bad advice about how to fix a boat can cost several people their lives. Hey Ron, you're the resident boatbuilding expert, what's your opinion? If you're _not_ a "boatbuilding expert" then perhaps you should not be quite so quick to criticize the opinions of others who have relevant experience. I doubt that the Titebond folks are paying you to advocate the use of their product in boatbuilding, so why are you so upset about the notion that it is not suited to that purpose? JOAT We've got a lot of experience of not having any experience. - Nanny Ogg -- --John Reply to jclarke at ae tee tee global dot net (was jclarke at eye bee em dot net) |
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Replacing gunnel on my canoe (slightly OT)
On Thu, 15 Jul 2004 18:31:05 GMT, "toller" wrote:
Hi toller, I,ve built a few strippers and done some of the type of work you're looking at. My thinking is this: If you're going to splice a piece of gunwale in, a scarf joint is the way to go, but there are some trade-offs that don't really make it worthwhile. 1) appearance 2) distortion 3) possible other rot areas. You're probably better off to replace the gunwales full length and go with an inwhale and outwhale.. I suggest 1/2 x 5/8 ash (not hard to get). Single strips of clear ash will not need any kind of preparation for the curves of a canoe. Ripping the strips is not exactly the hardest job in the world, even with a mediocre saw (table, band, or radial-arm). If you have no saw, find somebody. The ripping is only a 15 minute job. Radius and taper ends before assembly. Clamp, glue and screw (stainless) from midship toward the ends - screw from outside-in through the hull, countersink and plug afterwards. You can unclamp as you sink screws, so you only need about 12 clamps if your working both sides together. Use only marine epoxy with fillers as glue. It is extremely strong and will encapsulate the ash rot (ash is not particularly rot-resistant). Use a slow-set epoxy, and keep the hull clean as you work. Seal the finished product with clear varnish that has UV inhibiters. (Clipper is good). This is not a big ticket repair. Virgin gunwales will probably have the coast guard on you case to slow down.. ( :=) .. I have a 10' canoe. The gunnels are a pair of 3/4"x5/8" pieces of what looks like spruce. (one pair on either side) One piece has about 2' rotted away. We are still using the canoe, but it can't be a good idea. Replacing the entire gunnel would be difficult, both because of the way the canoe is build and my inability to cut a 10' strip of wood. So, I would like to replace the rotten part, plus some good wood on either size, for a total of 4'. I cut 2 5/16"x3/4" pieces of cherry 4' long. (somewhere I read that cherry is rot resistance, plus I happened to have a suitable scrap of cherry). I can easily bend the strip to the required size. So, what I plan is to install one 5/16" piece to the canoe by screwing it to the other half of the gunnel. Then I will glue the second 5/16" piece to the first, holding it in place with screws and some clamps. 1) Does this make any sense? Will the cherry strips ever relax, or will they always be under tension? 2) Is Titebond2 adequate, or should I use epoxy? Oddly, one 5/16" strip is much more flexible that the other, eventhough they came from the same 3/4" piece of wood and look identical. |
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Replacing gunnel on my canoe (slightly OT)
wrote:
On Fri, 16 Jul 2004 03:17:41 -0400, (J T) wrote: Thu, Jul 15, 2004, 11:48pm lid (J.*Clarke) says: snip On a canoe, I'd use resorcinol myself, but epoxy should be fine. I wouldn't trust _any_ PVA glue on a stressed part of any boat. Having your glue let go at sea can ruin your whole day snip OK, I'll bite. Why would you imply that a PVA glue would "let go at sea" on a canoe, stressed part or not? tt's not going to be submerged, at least not in normal use. And, it's not like wood glue has never been used in boatbuilding before. I'd imagine it'll wind up with a varnish, or other protective coating too, which will keep moisture away from the glue. Do you know of a stressed PVA glue joint that "let go at sea"? Hey Ron, you're the resident boatbuilding expert, what's your opinion? JOAT I ain't Ron. I'm not even a boatbuilder. but I do know that PVA glues have a reputation for creeping under stress and for not being terribly waterproof. after all, they are formulations of poly.VINYL.acetate. vinyl beinc a plastic, and plastic being a word meaning easily deformed. While one definition of "plastic" is "easily deformed" the term encompasses a vast range of materials these days, and some of them are not nearly as easily deformed as you might think. PVA creeps because that's one of its properties, not because it's plastic per se. Epoxy is also a plastic and it is much less subject to creep. -- --John Reply to jclarke at ae tee tee global dot net (was jclarke at eye bee em dot net) |
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Replacing gunnel on my canoe (slightly OT)
"toller" wrote in message ...
I have a 10' canoe. The gunnels are a pair of 3/4"x5/8" pieces of what looks like spruce. (one pair on either side) One piece has about 2' rotted away. We are still using the canoe, but it can't be a good idea. Replacing the entire gunnel would be difficult, both because of the way the canoe is build and my inability to cut a 10' strip of wood. So, I would like to replace the rotten part, plus some good wood on either size, for a total of 4'. I cut 2 5/16"x3/4" pieces of cherry 4' long. (somewhere I read that cherry is rot resistance, plus I happened to have a suitable scrap of cherry). I can easily bend the strip to the required size. So, what I plan is to install one 5/16" piece to the canoe by screwing it to the other half of the gunnel. Then I will glue the second 5/16" piece to the first, holding it in place with screws and some clamps. 1) Does this make any sense? Will the cherry strips ever relax, or will they always be under tension? 2) Is Titebond2 adequate, or should I use epoxy? Oddly, one 5/16" strip is much more flexible that the other, eventhough they came from the same 3/4" piece of wood and look identical. Edd has the right idea. Replace the entire gunnels , ash or white oak. Use epoxy, read Edd's post again , he explains it better than I. mike |
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Replacing gunnel on my canoe (slightly OT)
mike wrote:
"toller" wrote in message ... I have a 10' canoe. The gunnels are a pair of 3/4"x5/8" pieces of what looks like spruce. (one pair on either side) One piece has about 2' rotted away. We are still using the canoe, but it can't be a good idea. Replacing the entire gunnel would be difficult, both because of the way the canoe is build and my inability to cut a 10' strip of wood. So, I would like to replace the rotten part, plus some good wood on either size, for a total of 4'. I cut 2 5/16"x3/4" pieces of cherry 4' long. (somewhere I read that cherry is rot resistance, plus I happened to have a suitable scrap of cherry). I can easily bend the strip to the required size. So, what I plan is to install one 5/16" piece to the canoe by screwing it to the other half of the gunnel. Then I will glue the second 5/16" piece to the first, holding it in place with screws and some clamps. 1) Does this make any sense? Will the cherry strips ever relax, or will they always be under tension? 2) Is Titebond2 adequate, or should I use epoxy? Oddly, one 5/16" strip is much more flexible that the other, eventhough they came from the same 3/4" piece of wood and look identical. Edd has the right idea. Replace the entire gunnels , ash or white oak. Use epoxy, read Edd's post again , he explains it better than I. FWIW, I agree that that's certainly the _right_ way to go about it. mike -- --John Reply to jclarke at ae tee tee global dot net (was jclarke at eye bee em dot net) |
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Replacing gunnel on my canoe (slightly OT)
Fri, Jul 16, 2004, 9:59am From: lid (J.=A0Clarke) put out some stuff I'll reply to one part at a time: Because having spent a fair part of my life out of sight of land I have a great respect for the ability of the sea, lake, river, stream, or pond to damage anything that is floating on it. That's a Hell of a blanket statement. Damage anything floating? Sure, the Titanic sank on it's maiden voyage, but now the theory is a fire in a cola bunker, not hitting an iceburg did it. Unlss your'r out in the middle of the ocean, most people with any sense head for shore if a storm comes up and they're in a boat. It is a truism that the sea can kill any ship and the wise sailor gives it as little help in that endeavor as he can. That's why you go ashore, if you can. Ever chip through the rust on a warship, built from the finest steel in the world, and covered with high-quality marine enamel from the time that it was first built That, only one of the many reasons I didn't join the Navy. (the Navy will spend for good paint because they don't like to have their ships turn to rust) From the lowest bideder. 90 feet above the waterline where a landlubber would assume that it never gets exposed to salt water, Crossed the posd twice, in troopships, seen spray go completely over the entire ship. and find after chipping through an inch and a half of rust that there wasn't anything there but rust? Then apparently neither the paint, or the steel, were that high quality. First time you do that you lose all faith in the notion that distance above the waterline and protective coatings guarantee that the material will never be wet. I never had that faith in the first place. A 2 1/2 ton truck full of troops gets a flat, you're already on land. A ship gets a hole, you might be miles from land. Hehehe It's when things get abnormal that people die. In any case, the particular part that he was replacing was rotted out. That means that it was kept wet for a fair amount of time. No, it doesn't. It means it was exposed to the right conditions to make it rot. Resorcinol glue _is_ "wood glue". It's just truly waterproof wood glue. However, it is not used in day-to-day use, for woodworking. It is normally used in boatbuilding. Now you see, there I have the advantage of you because I have learned in the real world that (a) paint, varnish, etc, canot be counted on to keep the underlying surface dry when it is covered by standing water and (b) even the very expensive multipart coatings have a limited service life in a marine environment. If the "varnish or other protective coating" will keep moisture away from the glue" then why did the wood rot out in the first place? Or will it just magically keep moisture away from the glue and not from the surrounding wood? And, you think no one else has learned any of that? That's one reason for the words revarnish, repaint, etc. But, I doubt there's gonna be a whole lot of standing water on a canoe gunnel. By the way, epoxy is not 100% waterproof, as apparently stell isn't either. Epoxy will eventually let water thru. Rescorcinal I don't know about. And, don't care. I don't know anyone who was stupid enough to use PVA glue in a stressed joint on a boat. Ah, here's where you confused me. You see, you repied to Toller, who asked about using Titebond. "Thu, Jul 15, 2004, 11:48pm From: lid (J.=A0Clarke) toller wrote: snip 2) Is Titebond2 adequate, or should I use epoxy? To which you replied: On a canoe, I'd use resorcinol myself, but epoxy should be fine. I wouldn't trust _any_ PVA glue on a stressed part of any boat. Having your glue let go at sea can ruin your whole day snip " That's where I got PVA. Well, Titebond II is a aliphatic resin glue, not a PVA glue. I would say Titebond II, clamped for 24 hours, should work. However I do remember a laminated tiller, nicely carved by a local artisan and glued together with what he assured us was "waterproof glue", lying on the sole of the cockpit completely delaminated. And that tiller was under no stress to speak of and was subject to less water exposure than a canoe gunwale when it came apart. Well, that statement sure leaves a lnot of information missing. Type of wood, type of glue, clamped, clamp time, protective coating, etc. I saw a delaminated plywood sign, no paint or protective coating. Took about 5 years outside to deliaminate. Look, if you want to stick your neck out that's fine, but when you start advising other people to do dangerous things while pretending they are not dangerous you're behaving irresponsibly. Well, I wasn't aware that a repair to a canoe gunnel, using Titebond II would be a life-threatening experience. Grok the concept--bad advice about how to use a table saw may cost somebody a finger. Bad advice about how to fix a boat can cost several people their lives. I don't recall telling anyone how to use a table saw. i also don't recall telling anyone how to fix a boat. I do think Titebond II would suffice in the repair of the canoe gunnel. If you're _not_ a "boatbuilding expert" then perhaps you should not be quite so quick to criticize the opinions of others who have relevant experience. No, I'm not an expert, few people are, at anything. I also wasn't aware that you are. You might have said. Hmm, just reread your statement. Relevant experience. An nteresting statement. Being in the Navy is relevant? If that's so, it's an interesting fact, that if you count all floating craft, of all sizes, Disney is suppoed to have the fifth largest navy in the world. Regardless, people in canoes, or small boats should be wearing approve floatation devises. I doubt that the Titebond folks are paying you to advocate the use of their product in boatbuilding, so why are you so upset about the notion that it is not suited to that purpose? They aren't, I just like Titebond II. Found it meets my needs nicely. And, I'm not advocating it's use in boatbuilding. I think it would work for the repair in question. You apparently seem to have a major problem with that concept. Sure, resorcinal, and epoxy will work, they'd both be overkill too. I know of a number of people who build boats and/or canoes for money that wouldn't glue at all, just screws for holding - with varnish coat, of course, for protection. My personal favorites for boatbuilding are strip built, and tack and tape (using epoxy and fibreglass). I recently read of a 50' steam boat, originally built in the 1890s. The hull was four layers of mahogany, copper wire sewn. It was recently "restored". The restorer apparently couldn't make it waterproof again, so used epoxy between the layers. Just found that interesting, so tossed it out there. A correct statement would be that I would use Titebond II IN boatbuilding. But, not FOR boatbuilding. In plainer language, I would use it in some places, but NOT in critical areas. JOAT We've got a lot of experience of not having any experience. - Nanny Ogg |
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Replacing gunnel on my canoe (slightly OT)
J T wrote:
Fri, Jul 16, 2004, 9:59am From: lid (J.*Clarke) put out some stuff I'll reply to one part at a time: Because having spent a fair part of my life out of sight of land I have a great respect for the ability of the sea, lake, river, stream, or pond to damage anything that is floating on it. That's a Hell of a blanket statement. Damage anything floating? Sure, the Titanic sank on it's maiden voyage, but now the theory is a fire in a cola bunker, A "cola bunker"? Now why would they be transporting cola from the UK to the US? Perhaps you meant "coal bunker"? If so, you've got that story badly garbled--the conspiracy theory there is that the ship was traveling at excessive speed in the hope of getting to New York before the coal fire spread and the fact is that the fire was out before the iceberg was struck. Regardless, the Titanic is far from the only vessel that has ever sunk, and a canoe is far less capable than the Titanic. Unlss your'r out in the middle of the ocean, most people with any sense head for shore if a storm comes up and they're in a boat. A storm is far from the only way to come to grief in a boat. It is a truism that the sea can kill any ship and the wise sailor gives it as little help in that endeavor as he can. That's why you go ashore, if you can. If you are going to spend all your time ashore then why have a boat at all? Ever chip through the rust on a warship, built from the finest steel in the world, and covered with high-quality marine enamel from the time that it was first built That, only one of the many reasons I didn't join the Navy. Perhaps if you had you would know something about boats. (the Navy will spend for good paint because they don't like to have their ships turn to rust) From the lowest bideder. From the lowest bidder that meets spec. 90 feet above the waterline where a landlubber would assume that it never gets exposed to salt water, Crossed the posd twice, in troopships, seen spray go completely over the entire ship. And yet you stick with your notion that the gunwale on a canoe will never get wet? and find after chipping through an inch and a half of rust that there wasn't anything there but rust? Then apparently neither the paint, or the steel, were that high quality. Seems you know as much about steel as you do about boats. You can have very strong steel or very corrosion resistant steel but you can't have both. As for the paint, fine, let's accept your argument that the Navy doesn't know what kind of paint to use on ships. What makes you think the varnish on this canoe is going to be any better? First time you do that you lose all faith in the notion that distance above the waterline and protective coatings guarantee that the material will never be wet. I never had that faith in the first place. A 2 1/2 ton truck full of troops gets a flat, you're already on land. A ship gets a hole, you might be miles from land. Hehehe If you do not have such faith then why when anyone suggests that your precious titebond will get wet do you go on about coatings? It's when things get abnormal that people die. In any case, the particular part that he was replacing was rotted out. That means that it was kept wet for a fair amount of time. No, it doesn't. It means it was exposed to the right conditions to make it rot. And being kept dry as an Egyptian tomb is of course one of those conditions? Resorcinol glue _is_ "wood glue". It's just truly waterproof wood glue. However, it is not used in day-to-day use, for woodworking. It is normally used in boatbuilding. I see. So the only kind of glue that is "wood glue" is the kind of glue that is not used in boatbuilding. Now, if it is used in boatbuilding but not in day to day use, perhaps there is a reason? Hmmmm? Now you see, there I have the advantage of you because I have learned in the real world that (a) paint, varnish, etc, canot be counted on to keep the underlying surface dry when it is covered by standing water and (b) even the very expensive multipart coatings have a limited service life in a marine environment. If the "varnish or other protective coating" will keep moisture away from the glue" then why did the wood rot out in the first place? Or will it just magically keep moisture away from the glue and not from the surrounding wood? And, you think no one else has learned any of that? You clearly haven't. You may think you have and yet you keep insisting that paint will keep glue dry on a boat. That's one reason for the words revarnish, repaint, etc. But, I doubt there's gonna be a whole lot of standing water on a canoe gunnel. Perhaps not. But that's not the wya to bet. By the way, epoxy is not 100% waterproof, as apparently stell isn't either. Never claimed it was so what relevance do you believe that statement to have? Epoxy will eventually let water thru. Rescorcinal I don't know about. And, don't care. So you don't care about anything except your precious Titebond? I don't know anyone who was stupid enough to use PVA glue in a stressed joint on a boat. Ah, here's where you confused me. You see, you repied to Toller, who asked about using Titebond. "Thu, Jul 15, 2004, 11:48pm From: lid (J.*Clarke) toller wrote: snip 2) Is Titebond2 adequate, or should I use epoxy? To which you replied: On a canoe, I'd use resorcinol myself, but epoxy should be fine. I wouldn't trust _any_ PVA glue on a stressed part of any boat. Having your glue let go at sea can ruin your whole day snip " That's where I got PVA. Well, Titebond II is a aliphatic resin glue, not a PVA glue. I would say Titebond II, clamped for 24 hours, should work. You might want to research the composition of "aliphatic resin glue". You will find that it is PVA with additives. And you believe that with sufficient confidence that you would stake your kid's life on it? However I do remember a laminated tiller, nicely carved by a local artisan and glued together with what he assured us was "waterproof glue", lying on the sole of the cockpit completely delaminated. And that tiller was under no stress to speak of and was subject to less water exposure than a canoe gunwale when it came apart. Well, that statement sure leaves a lnot of information missing. Type of wood, type of glue, clamped, clamp time, protective coating, etc. About as much information as you don't have about this glue joint on the canoe. I saw a delaminated plywood sign, no paint or protective coating. Took about 5 years outside to deliaminate. I think you will find that exterior plywood is generally made with glue considerably more water resistant than Titebond II. Look, if you want to stick your neck out that's fine, but when you start advising other people to do dangerous things while pretending they are not dangerous you're behaving irresponsibly. Well, I wasn't aware that a repair to a canoe gunnel, using Titebond II would be a life-threatening experience. Perhaps you should improve your awareness. Grok the concept--bad advice about how to use a table saw may cost somebody a finger. Bad advice about how to fix a boat can cost several people their lives. I don't recall telling anyone how to use a table saw. i also don't recall telling anyone how to fix a boat. I do think Titebond II would suffice in the repair of the canoe gunnel. I see. So you are advising someone to repair a canoe gunwale (it is not a "gunnel", it is a "gunwale", by the way) using Titebong II glue but you are not telling someone who to fix a boat. Is it that you do not consider replacing part of a rotted out gunwale to be "fixing" or that you do not consider a canoe to be a "boat"? If you're _not_ a "boatbuilding expert" then perhaps you should not be quite so quick to criticize the opinions of others who have relevant experience. No, I'm not an expert, few people are, at anything. I also wasn't aware that you are. You might have said. Why? Hmm, just reread your statement. Relevant experience. An nteresting statement. Being in the Navy is relevant? If that's so, it's an interesting fact, that if you count all floating craft, of all sizes, Disney is suppoed to have the fifth largest navy in the world. Regardless, people in canoes, or small boats should be wearing approve floatation devises. I see. So it's all right to make a crappy repair and have the boat sink because everybody should be wearing a life jacket. Now I know why some states have started requiring licenses for boat operators. I doubt that the Titebond folks are paying you to advocate the use of their product in boatbuilding, so why are you so upset about the notion that it is not suited to that purpose? They aren't, I just like Titebond II. I like it too, but I would not use it to fix a boat, or to repair a gunwale on a canoe since you don't seem to consider that "fixing a boat". Found it meets my needs nicely. And, I'm not advocating it's use in boatbuilding. Yes, you are. I think it would work for the repair in question. It might. Or it might not. I'd rather go with something I was _sure_ would work. You apparently seem to have a major problem with that concept. The problem I have is with your view that "might work" is an adequate standard for equipment whose failure could put lives in danger. Sure, resorcinal, and epoxy will work, they'd both be overkill too. Better to overkill than to underkill. I know of a number of people who build boats and/or canoes for money that wouldn't glue at all, just screws for holding - with varnish coat, of course, for protection. Perhaps the fact that they don't trust _any_ glue in that application should tell you something. My personal favorites for boatbuilding are strip built, and tack and tape (using epoxy and fibreglass). That's nice until you have to fix one. I recently read of a 50' steam boat, originally built in the 1890s. The hull was four layers of mahogany, copper wire sewn. It was recently "restored". The restorer apparently couldn't make it waterproof again, so used epoxy between the layers. Just found that interesting, so tossed it out there. A correct statement would be that I would use Titebond II IN boatbuilding. But, not FOR boatbuilding. In plainer language, I would use it in some places, but NOT in critical areas. And how would you decide what constitutes "critical areas"? Before you decide, you might want to read Sir Francis Chichester's account of the time that the knife rack let go while he was directly under it. And being chased around a DASH hangar by a Coke machine will give you a wonderful appreciation for the importance of seemingly minor structure such as the bracket that is supposed to hold the Coke machine in place. JOAT We've got a lot of experience of not having any experience. - Nanny Ogg -- --John Reply to jclarke at ae tee tee global dot net (was jclarke at eye bee em dot net) |
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Replacing gunnel on my canoe (slightly OT)
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Replacing gunnel on my canoe (slightly OT)
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Replacing gunnel on my canoe (slightly OT)
I must agree with the comments hereon, having done this job myself more
than once. It is simplier than it seems, just takes time and care. Replace both gunnels, becasue of possible rot elsewhere and asthetics. Ash was traditional because it is strong and flexible. White oak is fine, and can be soaked or steamed to noodle limpness. You can get a local woodshop to rip and even plane or shape the wood for a nominal fee. Use epoxy for strength and waterproofness. Be careful not to glue gunnels to hull. If it's canvas be prepared to find rotten fabric under the rotten gunnel section. Go slow, think, and do your best. Canoes are beautiful, and should be treated lovingly. If you're not up to it, get someone else to do it right. It will be money well spent. You'll regret anything else. Luk. VR, Tom toller wrote: I have a 10' canoe. The gunnels are a pair of 3/4"x5/8" pieces of what looks like spruce. (one pair on either side) One piece has about 2' rotted away. We are still using the canoe, but it can't be a good idea. Replacing the entire gunnel would be difficult, both because of the way the canoe is build and my inability to cut a 10' strip of wood. So, I would like to replace the rotten part, plus some good wood on either size, for a total of 4'. I cut 2 5/16"x3/4" pieces of cherry 4' long. (somewhere I read that cherry is rot resistance, plus I happened to have a suitable scrap of cherry). I can easily bend the strip to the required size. So, what I plan is to install one 5/16" piece to the canoe by screwing it to the other half of the gunnel. Then I will glue the second 5/16" piece to the first, holding it in place with screws and some clamps. 1) Does this make any sense? Will the cherry strips ever relax, or will they always be under tension? 2) Is Titebond2 adequate, or should I use epoxy? Oddly, one 5/16" strip is much more flexible that the other, eventhough they came from the same 3/4" piece of wood and look identical. |
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Replacing gunnel on my canoe (slightly OT)
J T wrote:
Sat, Jul 17, 2004, 11:01pm lid (J.*Clarke) says a lot: snipped Well, I've certainly got no response to any of that. You obviously are an expert, know everything there is to know about it all, and apparently everything I know, or learned, or heard, or thought, is wrong. If you mean by "know everything about it all" that "Titebond II is not the right glue to use to fix a busted boat" then, yeah, by that standard I know everything about it all. But, seeing as you called me on my spelling, you spelled "who", when it probably should have been "how". Sorry, but "cola bunkers" struck me as sufficiently humerous to be worthy of note. And, it was not exterior plywood. Now let's see, you're talking about an outdoor sign that was not made on exterior plywood? I'm sorry, but why would someone use anything but exterior plywood for an outdoor sign? It was entertaining for awhile, and enlightening. What would you advise using, to make a wooden boat, in the 15-18 foot range: Wood, adhesives, fasteners, protective coating, etc.? I would advise first finding the local watermen in your area (the people who _work_ on the water) and finding out what they use. There may be local considerations that make one type preferable to another. If you're not in an area where there are such, then see if there are any "traditional" designs that have historically been popular in your area. Then obtain a set of plans for a boat appropriate to the use intended and follow the recommendations of the designer. Boat design is a specialized art. Far more to consider than you might imagine if it is to be stable and give good performance. Take a look through a text on Naval Architecture if you don't believe me. And don't assume that because it's a "little boat" those considerations don't apply. There's also the matter of local conditions--see what's popular among the working watermen of your area and that's probably the way to go. I'm not a naval architect and don't pretend to be. Oh, yes, it would live on a trailer, except when in the water, would not be overnight in the water, be covered when not in use, and be checked weekly for water insited the boat, whether used or not. Again, go with what the designer recommends. From your description below whatever you pick will probably have a transom plug, pull it when it's on the trailer and water should not be an issue as long as nothing is blocking the plug. Just make sure you put it back before you launch. For a trailer boat ply, either sheet or cold-molded, is probably the best bet unless you want to tool up to do traditional dory construction--it's going to be going through alternate wet and dry cycles and you want something that doesn't move much and so doesn't work itself apart. If you manage to knock a hole in it though the repair is not going to be as simple as replacing a board. Would be used on lakes, probably rivers, and need to be able to be run up on banks, landings, possibly run up (accidently) on a submerged stump or rock - not faster than a slow trolling speed - without being holed (minor leakage from such a collision would be acceptable, as it would not deter getting back to the landing). Just get a Zodiac. Designed for that use. A 16-footer will fit in the trunk to most cars. I'd like your expertise on that. And, boat design suggestion too, I want something that looks good, and works right - but no sailboat, something to take up to a 10 HP outboard. Something you leave out is how much work you're willing to put into it. There are traditional methods that require that you "make the tool to make the tool" before you start construction, and there are "quick build" methods that require a lot less preparation. Either can produce a usable and reasonably attractive boat in your size range, which you prefer depends on your personality. If you want it to look good--that lets out the Zodiac. When you say "lakes" define "lakes"--the Great Lakes can kill oceangoing ships and are deep enough for submarines to go do test depth. Crystal Lake down the road one can easily swim across. How far into that lake are you planning to go? Ditto "river"--the Saint Johns, which has maybe 20 feet of elevation difference between the source and the mouth, is a very different critter from the Colorado or the Snake, whose livelier parts can be safely navigated only by experts in boats designed for the purpose. Sounds like you're looking for a basic skiff, which these days are usually plywood on frame or bulkhead, but local conditions may call for something else. How good do you want it to look and how much effort do you want to put into it? Bright finished mahogany strip plank is gorgeous but there's a lot of work involved in keeping it that way. Marine ply is easy but it looks like plywood. Can still look pretty good with good design and careful finish though. As for your leakage concern, the "traditional" carvel-plank construction will generally "give" a little on impact and may spring the seams, which makes for a slow leak. Ply or strip plank will either not leak at all or get a real hole. Carvel plank though doesn't work very well for a trailer boat as it depends on the wood swelling to close the seams so it will always be leaking in a trailer boat. Traditional dory construction might be a good option--they're designed to go in and out of the water and take a beating and are remarkably seaworthy. Obviously none of my ideas on the subkect are worth Jack, If you've never spent much time on the water and you're setting out to design one with no training, then you've got _that_ right. Not quite as risky as setting out to design an airplane with no training, but close. so I need expert advice, before I commit to any materials purchasing, or boatbuilding, because I obviously can't trust my sons' lives to my knowledge, or lack thereof, of building boats. Help me Obi-Wan. This is a question like "how high is up", a topic of endless discussion and speculation. Something that I might find immensely appealing you might dislike intensively. I'm not really into trailer boats anyway so I'd have to do some research to come up with specifics. Wooden Boat, Mystic Seaport Museum, and John Gardner, among others, have books of study plans--go through those and you'll have some ideas and know the names of many of the major designers. Most of these will be for "traditional" construction. The "Glen L" site has a wide range of plans intended for amateur construction, and they've been around long enough to have established a track record. Not my cup of tea, but you might like. JOAT We've got a lot of experience of not having any experience. - Nanny Ogg -- --John Reply to jclarke at ae tee tee global dot net (was jclarke at eye bee em dot net) |
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Replacing gunnel on my canoe (slightly OT)
On Sun, 18 Jul 2004 09:35:53 -0400, "J. Clarke"
wrote: And, it was not exterior plywood. Now let's see, you're talking about an outdoor sign that was not made on exterior plywood? I'm sorry, but why would someone use anything but exterior plywood for an outdoor sign? same reason they'd use pva on a boat.... |
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Replacing gunnel on my canoe (slightly OT)
J T wrote:
Sun, Jul 18, 2004, 9:35am lid (J.*Clarke) says: snip Now let's see, you're talking about an outdoor sign that was not made on exterior plywood? I'm sorry, but why would someone use anything but exterior plywood for an outdoor sign? I didn't ask. I would advise first finding the local watermen in your area (the people who _work_ on the water) and finding out what they use. snip Exterior plywood, butyl caulking, roofing nails. What kind of _boat_ they use. Take a look through a text on Naval Architecture if you don't believe me. snip Done. see what's popular among the working watermen of your area and that's probably the way to go. snip Exterior plywood, butyl caulk, roofing nails. I don't think so. Again, what kind of boat, not what kind of materials. Watermen don't generally build boats, they buy them from boatbuilders. From your description below whatever you pick will probably have a transom plug, snip No. Checked after use, any water removed, sponged dry. Transom plug - something more to remember, and potential leak. For a trailer boat ply, snip Which is what was planned all along. Just get a Zodiac. snip Ugly, expensive, not what I want. When you say "lakes" define "lakes"--the Great Lakes can kill oceangoing ships and are deep enough for submarines to go do test depth. snip If I meant Great Lakes, I'd have said. A lake, say up to 5 miles long, maybe 1/2 to 1 miles wide. Not going to kick up too bad then unless a vortex off a hill hits a resonance of the lake, then the whole thing can slosh. Ditto "river" snip I no rapids, or river in a flood stage. Sounds like you're looking for a basic skiff, snip No. How good do you want it to look and how much effort do you want to put into it? snip My definition of look good is not yours, I can tell that. Let's just say straight lines, or curved curves, and neatly painted. And, no lapstrake planking, or anything like that. Traditional dory construction might be a good option--snip Why not? Straight lines, neatly painted. Not. If you've never spent much time on the water and you're setting out to design one with no training, then you've got _that_ right. Not quite as risky as setting out to design an airplane with no training, but close. snip Yes, I've been on water. No, I've not had training designing. But, it ain't rocket science either. Define "metacentric height". Yes, it's possible to make a usable boat from a hollow log with no calculation whatsoever. I was under the impression that you wanted something a little nicer than that. Wooden Boat, Mystic Seaport Museum, and John Gardner, among others, have books of study plans-- snip I'm well aware of those, own study plan books, plus a collection of WoodenBoat magazine. I'm familiar with Glen-L, Clark, Devlin, Stevenson, and other boat plan sellers, and have material from some. I also own books on boatbuilding by Philip C. Bolger, Harold "Dynamite "Payson, John Gardner, Howard Chappelle, a number of other authors I can't recall just now, one or two books from the Naval Institute Press, and at least one book on oceangoing ship design. Most of those books have been owned by me for up to 20+ years, and I think the latest one I've had for at least two years. And, they've all been read, more than once. I've done my homwork, I don't know why you would think I hadn't. Because you're behaving as if you hadn't. I think I can be trusted to build a smll boat for fishing that won't sink, or fly apart in the middle of a lake. So, I'm done. There's more to it than "won't sink or fly apart in the middle of a lake". If it's motion is so rapid that you're permanently sea-sick or if it's so unstable that all you can do is get it to go around in circles or if it decides to pitch you overboard every time you sneeze that's not good either. JOAT We've got a lot of experience of not having any experience. - Nanny Ogg -- --John Reply to jclarke at ae tee tee global dot net (was jclarke at eye bee em dot net) |
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