Materials + Kits
Good boats are built with good materials.
Choosing a kit supplier. (All kits are not created equal.)
It is inevitable that you can find a facsimile of most good things. A cheap knock-off Rolex is not a Rolex and a cheap strip-planked boat kit is not a Bear Mountain Kit. It is the difference between a manufacturer taking pride in producing the best possible product and someone trying to put the least amount of value into a product that resembles the genuine article. There are times when buying on price alone is a necessary decision but it doesn’t always end up being good value.
Understanding what to expect in a small boat kit and how quality benefits you will help put saving a few dollars in perspective. If you put a price on the time you will spend building your boat, buying the best materials will be a small part of your investment and a big part of your pride and satisfaction.
Planking – What to look for?
In our boat shop, we make a point of looking for ‘Cheap Tricks’. This does not mean that we lower our standards but rather we look for ‘the shortest route to the best results’. Nothing contributes more to getting a good job done quickly than the right materials accurately machined.
The Ideal Plank is full length, edge grain with a precisely machined bead and cove edges and a consistent ¼” thickness. (See Canoecraft or KayakCraft for complete information re; choosing wood and machining planking.)
Western Red Cedar is the most common wood species used for strip planking. It is lightweight, beautiful to look at, a pleasure to work with and for a premium price, it is available in long clear lengths. Clear twenty-foot cedar planks generally come from old growth trees. The reason these trees were not cut in the past is because they were too difficult or costly to retrieve. In order to harvest these mature trees, expensive methods of harvest such as helicopter logging must be used.
The number of short planks included in a kit is an indication of the cheap, low-grade of cedar being used. The short planks are a result of working around defects such as knots and splits. Because the wood is coming from smaller logs, a mixture of edge and flat grain should be expected. Flat grain has an interesting though busy grain pattern. The problem is that the pattern is made up from a combination of hard and soft grain; it is miserable to shape with a hand plane and the more you sand it, the wavier it becomes.
With extra care, a fair hull is possible using short planks. A full-length plank will bend around the mold in a fair, natural curve. Making up the length from several short pieces has a tendency to make a hard spot in the curve where the planks join. Using various tricks, it is possible to keep the curve fair but it does take time and strict attention to avoid flat spots in the hull.
Arranging the planks to create a visual pattern is important to some builders. Working with random short planks has a tendency to resemble parquet flooring. If this is not the style you had in mind, you will want the control and choice that comes with full length planks packaged in the order they were cut.
Accurately machined bead and cove edges.
The way the plank edges fit together have everything to do with the pleasure factor in planking your hull. Poorly machined edges create all kinds of extra work and annoying complications.
When the bead or cove is machined off center, there will be a step between each plank. The high plank will have to be shaped down to meet the low plank and the process repeated again on the inside of the hull. Not only does this add considerably to the dusty part of your building time, reducing the thickness of the plank also reduces the stiffness of the hull.
The depth of the cove is critical. The ideal depth will show the edges being slightly flat, about 1/64” wide of equal width on both edges. If the flat is equal on both sides, the cove is centered. If the cove is to shallow, there will be a crack on both sides of the joint. While the crack doesn’t extend all the way through, the crack must be filled before applying the fiberglass and epoxy resin; if not filled, air will be trapped in the void.
When the cove is machined too deep, you will see both edges ending thin like a feather. It is impossible to handle this plank without damaging the edges. When the edge breaks off, extra steps are added to the project. The biggest problem is not having to fill the voids but cleaning splinters out of the cove before installing the next plank. Leaving the splinters in will take the project to another level of unnecessary problem solving.
Inconsistent machining will allow the planks to fit in some places but leave the joint open and loose in other areas. It may look secure until the staples are removed to release the planking from the mold and the joint opens up. The problem is fixable but it is a learning opportunity best avoided.
What Epoxy do you recommend?
The epoxy resin is what holds a strip-planked/epoxy hull together; it is the main component in the structure of the hull. The epoxy resin in a kit accounts for a significant portion of the total cost of the kit; including a cheap resin significantly reduces the cost of the kit but is that doing you a favor? While there are some places where you can compromise and reduce the cost of the building project, using less than the best epoxy resin is the last place you want to economize.
We have been using West® System epoxy for more than forty years and have complete faith in the quality and integrity of their products. They have consistently worked to make their epoxy system safer and easier to use and maintain. While there are many epoxy formulations, very few are engineered to be compatible with wood. We have tested several of the better epoxy resin systems but the West® System is still the only resin system we would recommend for safe, predictable results and being best suited to this type of construction.
What hardener do you recommend?
105 Resin / 207 Special Coating Hardener - Recommended where an exceptionally clear finish is needed to enhance the woods natural beauty. Designed to work well in cool, damp conditions without clouding. If your building environment is unpredictable, we recommend the 105/207 resin system. Each kayak or canoe requires about 2 gallons (or 2 'B' Packs) of resin/hardener for laying up the fiberglass. If you are building more than two canoes a "C" Pack is most economical.
What about Fibreglass cloth?
It is important to use a cloth that is compatible with the epoxy resin. To facilitate the glass fibers bonding to the resin, a finish or interface is applied to the fibers. There are a number of finishes available for specific resin systems. The finish on cloth designed for polyester resin must be dissolved by the styrene in the resin. Epoxy, being 100% solids has no solvent to dissolve the finish thus this cloth would be unsuitable for our use. This is the most common cloth available and the cheapest but the results for our purpose are questionable. When the glass fibers are not bonded to the resin, the peel strength is compromised and a less than clear finish is quite possible.
Packaging and shipping is also important. The cloth should be carefully rolled to avoid wrinkles. Hard creases in the cloth will not want to lie down and become a problem to deal with.