08 Apr. 1995|
Building a cedar strip canoe cost,free woodworking plans for birdhouses,cabin loft blueprints - For Begninners
I've tried to provide a significant amount of detail here, especially in regard to problem areas and pivotal decisions, in hopes that the information can assist others who are considering building a canoe or similar project. The MDF forms are attached to squared hardwood blocks using nuts and bolts, and the blocks are clamped to the strongback. Steamer: You can make a steamer using a camping stove, large pot with a lid, some simple fittings, flexible metal pipe, and 4" diameter PVC or ABS pipe (don't seal it up tight, or you will be making a very dangerous steam bomb). Many strip canoes have hardwood stems on the ends to which the upcoming cedar strips are attached. Speaking of clamps: I decided to make the canoe myself after seeing how much it would cost to buy one. In addition to your machining space, you need a clear, sheltered, dry, level space at least 10' x 20' for canoe assembly; the larger, the better.
But back to the stems: Some designs have no stems, and the wood strips overlap and glue to each other at the ends. Being used to working with wood glues, I'm used to short clamp times and having joints be able to take a little stress within an hour of assembly. With the inner stems in place on the forms, begin gluing the prepared strips to each other and the stems.
The latex hoses are tied to one jaw of a spring clamp; the clamp can be attached anywhere along the bottom edge of the forms, allowing for easy adjustment of pressure amplitude and direction.
Gluing the strips went rapidly until I reached the bilge area, where there is a significant twist in the boards. Lost some pictures, here, of the strips all installed on one side and trimmed to the centerline. Strip installation becomes increasingly-frustrating (and profanity-laden) as you approach the final few strips.
Without the interior fiberglass and supporting rails and thwarts, the canoe sags somewhat now that it is off of the forms. Installed the thwarts and allow the canoe to settle into its final shape over a couple days. Some makers have commented about thwarts and seats getting rammed through the hull walls during compression, so all such components have been designed on my build so that cannot happen. Noah's Marine Supply out of Canada for initial fiberglass, epoxy and application tools order.
They were bored after about 30 minutes, so we walked over to a little hut and rented a canoe. Most less expensive canoes are symmetrical; you could cut them in half across the middle and wouldn't be able to tell the stern from the bow.
The forms and plans have no future utility unless you plan to make another canoe of the same design (and some designers of commercial plans will ask you not to do this without paying for another set of plans).
I got surprised more than once on this project when epoxied joints began to pull apart under the slightest stress, even after setting for a several hours. Some makers include accent strips and designs of various colors using different woods or by applying stains before fiberglassing. Common scrapers used for hardwood work are not useful here, because the soft cedar just tears out. You can see in the first image, below, that the latest strip starts out almost vertical at the stem, twists to almost horizontal in the middle, and then back to vertical at the other end. Cedar dust was generously mixed in this first coat so as to fill any minor cracks between the strips. You can also use the fast hardener if you don't wait too long (more than a few hours) between applications.
I made simple slings from 2x4s and carpet scraps to support the canoe on top of the strongback. Then cut them down to length, test fit, and sanded the surfaces where they would attach to the canoe. It is good to have an extra set of hands around for items like this, but an individual can do the rails if you dry clamp them in place first with a tight clamp every couple feet. It was really my own fault for allowing too much stress to focus right on the knot during installation.
For both overall strength and appearance, I used oak dowels in the joints (instead of metal hardware) to attach them directly to and in the same plane as the inwales.
But subtle irregularities alluded to earlier in the strip layup pretty much doubled the sanding time. It is also too large for me to handle on the water by myself if there is a strong current or wind; either situation requires two good paddlers. All other things being equal, you'll often save money by buying as close to you as possible, but these are the vendors that I used for a lot of the epoxy, fiberglass and unique tooling that can't be found in my own town. Start attaching strips to the forms at the part of the form closest to the strong back and work towards the center of the hull. I like to try my hand at something different from time to time and, recalling how much my children enjoyed the boating (and not the fishing), I turned my attention to making a cedar strip canoe in the late summer of 2007. I marked lines at one-foot intervals on the strongback; the faces of the forms are aligned with these lines. Yes, teak is heavy, but it is basically water and weatherproof, and I like how it looks with the cedar; most makers recommend ash and lighter hardwoods. Anyone can replace a radiator too; but having experience, skill and the right tools are the difference between a half-hour job done right the first time, and three days of torture, frustration, and an eventual tow to the nearby shop to complete a botched attempt. Some have an inner and an outer stem, where the outer stem acts as a strengthening end cap to the boat.
To do this I used a straight hardwood stick about 2 inches wide, an inch thick, and 16 inches long with sandpaper wrapped tightly around one end.
I didn't want to have to scarf-joint together a bunch of cedar strips, so I sought 18' clear cedar boards, but even in "clear cedar," only about one in ten boards was clear enough to work.
I don't have room in my shop for the tools and the canoe, so the canoe was built just in front of my garage under a temporary tent (until some local city personnel freaked out).
The more uniform your strips, the tighter you can fit them together and to the curvature of the forms, the better the whole project will go. If you have a smooth, tight, wood-to-wood mating surface and can apply good pressure to the joint, common wood glue (PVA) has strength similar to and is easier to work with than epoxy. But once completely cured, they seemed stronger than similar wood glue joints, are more resistant to water, and have good gap-filling properties. It wasn't necessarily the best in every category -- each epoxy has its own strength or weakness -- but overall, System 3 tended to do equal or better than most others that he tested. The latex hose is not strong enough to support that kind of twisting; it became difficult to do more than one or two strips at a time until I rounded the bend. In this case, using a razor knife, I cut half of the concave groove from the last installed strip, pressed the final strips into place, tapped it a few times with a soft-face mallet, then glued the removed edge back in.
You and any helpers should be wearing a full face respirator any time you are sanding cedar or epoxy and should keep it on for a considerable time afterward, at least until the air in the room has completely changed several times over! Some makers seem to prefer to drill a hole through the canoe siding and use a brass tube insert or the like. Canoe Craft by Ted Moores, Kayak Craft by Ted Moores, Building a Strip Canoe by Gil Gilpatrick. For example, having uniformly machined strips, making sure they are seated together well and close to the form curvature is important and will save a lot of frustration later. A file and sanding block can quickly smooth out any irregularities in the edges of the forms. The vertical lines are the centerline -- useful for aligning the forms and establishing the meeting lines for the bottom strips later on. If cost is an important factor, and you don't already have most of the accessory tools and supplies, you may be better off if you just go out and purchase a finished canoe direct from a professional maker, a retail store, or secondhand. Use the stick as a sanding block against the stem, doing a few inches at a time, installing cedar strips, sanding a few more inches, etc. Though knots can be acceptable and attractive in fine furniture, they create unacceptable weak points in long strips that have to bend and twist. Fabricating the strips took one pass through the bandsaw, and two passes through the router per strip. Also, many epoxies can be applied in temperatures approaching freezing whereas wood glue loses effectiveness under about 60 degrees.
This goes a lot faster if you use staples, but as an experienced woodworker used to making very nice pieces, I just can't bring myself to put staples into a visible face; that's just not right! I thought about that -- and actually purchased the bronze tube to do it -- then decided against it, realizing that my hardwood stems are much stronger than the siding, anyway.
Still have to try it out on the water, but I hope that it will be more comfortable than common canoe seats or kneeling in the bottom of the boat.
Though some steps of construction are tedious, a nice thing about many boats, and canoes in particular, is that they combine artistry, woodworking, and some interesting design problems. It is helpful to have at least one extra sacrificial strip on the outside of this bend, as the outermost strip tends to tear out and get damaged by the C-clamps.
You can also acquire everything as a kit (less the strongback) for about twice the cost of the raw materials. Considerable time, space, tooling and patience are all necessary to complete a strip canoe; the skills are similar to, but not exactly the same as, basic hardwood furniture construction. Keep one end against the nearest form and the sandpapered end against the stem, and the entire stick oriented in the same direction as the upcoming cedar strips. That is, though it can bond two close surfaces together well, it does not have much strength in and of itself -- it isn't good for irregular joints or gaps where strength may be critical. The stapleless method is painfully slow, but using a combination of latex hose and band clamps I was able to glue about four strips at a time without any staples. So I am pausing work on the canoe to make a greenhouse-like building area in my back yard with temperature and humidity controls. Because the strongback is straight and level, I used it as a reference to check the depth of the forms, measuring from the surface of the strongback to the centerline on the forms to make sure they are in the correct position.
As it is designed, its interior end is a focal point for routine and impact stress, and there is not much mechanical strength at that point; there is little more than a butt joint between the cedar strips and the stem as it approaches the end, held together, effectively, by the epoxy and fiberglass laminations. This means going through a retail store that allows you to pick through the lumber, paying a premium for prefabricated strips from kit supplier (perhaps $1000 or more for 80 18' strips with shipping), or overbuying in hopes that you'll get a decent number of clean boards.
Also, epoxy requires little or no clamping pressure; in fact, too much clamping pressure can be a bad thing especially with epoxy.
The band clamps keep the strips tight to the curvature of the forms, and the latex bands provide the edge pressure between the strips; the substantial inconvenience of this method is it requires additional space in front of the canoe to thread strips in under the band clamps.
Unevenness in the fabric tension creates areas where the epoxy can collect and lift the fabric slightly relative to the surrounding plane.
If you look really closely -- and you probably wouldn't notice it unless it was pointed out -- you can see areas on my finish that look a little lighter, less clear, than nearby ones. Once the edges are ready and everything is aligned, apply tape to the edges of the forms to prevent them from gluing to and damaging your canoe's interior; at first I was tempted to use wax, then realized that it might interfere with the epoxy to be applied later. Some people recommend just using a heat gun instead of steam; I didn't try it, but did see pictures of some pretty sharp bends made in individual strips with hot air only. But if you have the tooling to make the strips and a good source for lumber, you can save some serious money by making them yourself.
By lengthening and flaring it, the strips have more material to grab and hold onto at that stress point.
But when properly applied, either adhesive can create a joint that exceeds the strength of the surrounding wood.
I didn't think of using the band clamps until about half way into stripping; the result is that my initial strips didn't follow the curvature of the forms as closely as I'd have liked. A single red cedar tree trunk generally contains between 200 and 5000 board feet, depending on size -- as much as a hundred times that used by a typical strip canoe. I don't know how well it would work if attempting to bend multiple strips at the same time. If I make more canoes, I'm planning on making a bandsaw attachment that will complete a precise strip in one pass.
What this all means is that I have been purposefully stretching it out here towards the end. I made one edge as straight as possible so that it could act as an alignment reference for the upcoming forms, but the same result could be achieved by "snapping" a chalk line down the middle.