I had intended to write a new section about how I make strips, based on a chapter from Strip Building the Virginia - Reproductions of an Adirondack Classic, written by Mike Olivette and myself. Rather than butcher the chapter, I include it here in its entirety, with minor formatting concessions to Microsoft Front Page. The sketches are by Dick Millet.
Besides describing the strip making process, it is hoped it might encourage strip builders to add an Adirondack guideboat to their fleet, and also provides a sample of the flavor of the book. As for the book, we hope it will be published by the end on the year.
Chapter 8 – The Strips
Perhaps the most significant difference between a traditionally built guideboat and a modern stripped reproduction is the use of many narrow strips to cover the ribbed hull rather than the eight or so comparatively wide planks. John Gardner, writing about using modern methods and materials in the Durant book, suggests using narrow strips, waterproof glue, and epoxy to build a guideboat. At the time of his writing, the building of small paddle and rowing craft from edge-glued narrow wood strips was in its infancy. Strip widths were variable among builders, and edge treatment of the strips to improve the joints was almost non-existent. Some boats were built with simple edge glued joints with the edges beveled with a block plane, and a few had no edge treatment at all, depending instead on a lot of filler to close the inevitable gaps. Gardner mentions a double bevel on one edge fitting into a mating “V” notch cut into the other.
Some of today’s strip builders still use the rolling edge bevel; a few others simply bevel both edges to the same angle. By far, the most popular edge treatment being used by modern small boat strip builders is a half round bead cut on one edge that fits into a cove cut into the other. Such strips, when properly fitted, glued, and later faired, produce a hull that is smooth, solid, and gives the impression the tree grew it that way. In a guideboat, the strips lay flat against the ribs and the strip surfaces align evenly, requiring only a minimum of scraping and sanding to fair the joints between strips. Of course, in order to produce such a near perfect hull, we must begin with near perfect strips. It is those strips that we will make for stripping the Virginia.
The choice of wood species for constructing a strip built boat is most often dictated by availability, followed by cost. The two are often related – the desired wood may be available outside of the builder’s area, but at a significant increase in the cost. Fortunate is the builder who has a choice of suitable wood available at his local lumber dealer. The availability and cost factors have contributed to boats being stripped with various cedars, pine, redwood, or even recycled wood of dubious parentage. While a flat sawn plank of virtually any wood can be ripped into usable, if not suitable, planking strips, a few species stand out as favorites among modern builders. These are western red cedar, followed by redwood and white cedar. Quarter sawn eastern white pine is the choice of builders of traditionally planked guideboat hulls, but pine sees little use in general strip building. This is probably because wherever pine is commonly available, the lighter weight red cedar usually is also, and at comparable pricing. Redwood is difficult to find on the east coast, and when available, is priced higher than the more common red cedar.
Several other factors bode well for the use of red cedar for guideboat construction. Its ready availability has already been addressed. It is available in lengths up to 16 to 20 feet, is nearly knot free and straight grained, and is harvested from old growth stands. The old growth trees are also slow growing, producing a very tight grain structure. There is a wide variation in the color of the wood, ranging from a light cream to almost black. The most common color is various shades of reddish brown. When coated with epoxy and varnished, it has a very pleasing appearance that invites an admiring touch.
Making Strips vs. Buying Them
Builders who prefer not to make their own strips can find ready sources of edge-milled red cedar (see Appendix 6 for sources), as well as white cedar and redwood. Buying such strips shortens the building process by a few days, but at a significant increase in the cost of the finished boat. For example, good quality western red cedar strips are currently priced at approximately forty to forty five cents per lineal foot, depending on the supplier and the strip length you choose. You will need about sixty to seventy strips for your boat, which includes a couple to be used as sheer battens. Assuming you choose full-length, 18' strips, it will cost you roughly over $500, excluding any sales tax and shipping fees (or travel expenses if you pick them up yourself) just to strip your boat. If building only a single boat is contemplated, buying ready-made strips could be an attractive alternative to milling your own despite the additional cost.
The “standard” strip size commonly used for canoe and kayak building and sold by suppliers is 3/4" wide and 1/4" thick, with interlocking bead and cove edges. Some suppliers will mill special sizes, usually at a higher cost. Keep in mind that strip quality can vary considerably from one supplier to another. Most reputable suppliers will be happy to send you samples of their strips which may include different wood species, sizes, quality, etc.
Making strips is, of course, more economical than buying the ready-made product, amounting to roughly a quarter of the cost of ready-made strips. But there are trade offs. More equipment is necessary to make them, and there is a lot of noise and dust produced as by-products. The equipment needed is a table-mounted router with bits to cut the bead and cove edges, and a thickness planer. A table or band saw is assumed. Dust control is imperative, and hearing and breathing protection is strongly recommended. Most of these items are already found in a modestly equipped woodworker’s shop, with the exception of the router bits. The cost of a good set of bits can be easily recovered in the savings realized from just one boat.
Typical strip-built boats, i.e. canoes, kayaks, and guideboats, range between 12 and 18 feet long. Due to the curvature of the sides of the hull, the strips need to be around a foot longer than the length of the finished hull. This is only an approximation, since the beam of the craft will affect strip length requirements. A longer strip is needed for a 16-foot long guideboat with its 38" beam than for a kayak of the same length with a 24" beam. We found that strips 18 feet long were required for the 16-foot long Virginia. While western red cedar can be obtained in lengths up to 20 feet, milling such long planks provides more excitement than is really needed for building a boat. Getting planks that are 18 or 20 feet long from the lumberyard to the shop is also challenging. Towing long planks carefully secured to a trailer is one option. Another popular hauling technique involves lashing half of an extension ladder to the roof rack of a car and tying the planks to the ladder. A few feet may hang off the ends, but with the long support provided by the ladder, that is of little concern. If the choice is made to buy ready-made strips, the transporting problem is reduced to carrying them into the shop from the curb where the trucker dropped them.
Assuming the perfect plank has been safely brought into the shop, it still must be planed, cut, routed, and stored. That means extended infeed and outfeed tables for the saw and router, and shop space at least twice as long as the board, at least temporarily. Auxiliary shop space can sometimes be found, such as opening a normally closed door to provide space for a long infeed table. Another shop extension has been rumored to include an open laundry room window. What ever it takes….
The longest cedar available for building one of our boats was 16 feet long, which is too short when the bends required are considered. An assortment of 8, 10, and 12-foot planks was selected instead. The strips were cut and then scarfed(1) to 18-foot lengths before milling the edges. Some strips had one scarf joint; others had two. When these strips were mounted on the hull the joints were placed under a rib, leaving no joints visible on the inside of the boat. This particular boat was painted on the outside, which covered the joints on the outside of the hull. The other of our boats was varnished, but was built from natural full-length strips, eliminating the need for scarfing. The point is you do not need natural full-length strips to make a boat. Shorter strips may even be preferred at times, being easier to handle, less prone to having cove edges damaged by handling, and possibly less expensive than the extra long planks. The color and quality selection is also a lot better, there being more of the shorter planks available at the lumberyard than those big long honkers.
Since strips are cut from a flat plank, the thickness of the plank determines the width of the strip. Without going into the nomenclature used by the lumber industry for sizing board thickness, the common plank thicknesses range from an actual 3/4" to around 11/2". The red cedar used for home construction trim and decking is usually around 7/8", rough on one side. Construction lumber, e.g. spruce, is 11/2" thick, and so-called “five quarters” is about 11/8" thick. Common pine can be 3/4", 11/8", or 11/2".
Since the common strip width is 3/4", a plank at least that thickness is required. With the 7/8" cedar, the boards should be thickness planed to 3/4" before cutting strips. They could just as easily be cut into strips at the 7/8" plank thickness, and they could be used to build a boat. There are two reasons for not doing so. First, plank thickness should never be assumed to be consistent. Two nearly identical planks from the same pile in the same lumberyard may be of sufficiently different thickness to cause problems later. This is especially true if shorter strips must be joined in a scarf joint. Different thickness planks will produce strips of different widths, and scarfing such dissimilar strips together risks gaps in the finished hull, which will require filling. Second, the curvature of the hull is defined by the curve in the ribs. Mounting relatively wide strips against a curved rib will leave an inner surface consisting of several flats attempting to define a curve. It is similar to trying to draw a circle using only a series of connecting straight lines. The more numerous and shorter the straight lines are, the nearer to a true circle the figure becomes. If narrower strips are used to plank a hull, the fairer the curve becomes. Planing and sanding the ridges from the outside of the hull is normally done regardless of strip width, but the narrower the strips, the less wood has to be removed to fair the surface. On the inside of a stripped guideboat hull, the ribs prevent anything but a clean-up sanding, with extensive fairing in order to shape the hull being next to impossible. In our boats, cutting strips from planks all planed to a consistent 3/4" thickness proved to be acceptable on all points.
The planks are planed to 3/4" by alternately removing a little from each side until the desired thickness is obtained. Planing both sides cleans up any dings in the board, and exposes surfaces with equal moisture content and the same color. It also discourages cupping due to uneven moisture content. Trying to cut strips from a cupped board will likely produce strips with a lot of saw marks, and can be downright dangerous if the board binds while being ripped.
With the planks all planed to 3/4", we have to know strip thickness before ripping them up into strips. Although the planking thickness on the original Grant boats was 3/16" for the pine planks above the 1/4" thick garboard plank, a cedar stripped hull of that thickness would be of somewhat questionable strength without fiberglass inside and outside. The reduction in weight resulting from using 3/16" strips rather than the common 1/4" strips is negligible, considering that the weight of the strips is but a fraction of the weight of the entire craft. Some experienced builders, professionals among them, do build light weight canoes and kayaks from cedar strips as thin as 1/8", but such thin strips have no place in a guideboat. The stresses imparted by pulling on the hull-mounted oars are quite different than those produced by paddling a canoe or kayak, where the paddler’s pants provide the only attachment to the hull. The 1/4" thick strips are easier to make accurately, and are easier to work with. For the builder who chooses to buy strips, the 1/4" are readily available. Special orders for thinner strips could raise the price considerably. All of our boats have been built with the 1/4" strips with no consideration given to thinner stock, and no further consideration will be given here.
Western red cedar strips 3/4" wide and 1/4" thick are the target. Getting the width was easy. Getting the finished thickness takes a little more effort. Since we will be using a bead and cove edge treatment, and since the router bits commonly available for milling the edges are sized to 0.250", it is imperative that the router-ready strip thickness be 0.250" ± a few thousandths. This also assumes a consistent thickness the entire length of the strip. The consequences of failing to adhere to this seemingly rigid tolerance results in problems that could impact hull aesthetics and require significant time and effort to correct, if corrections would even be possible. For example, assume a long plank was run through a saw set to cut nominal 1/4" thick strips, and the edges of those strips were immediately routed. Unless the plank has a perfectly straight reference edge against a long fence and the wood shop has a very long infeed and outfeed table and possibly a stock feeder, it is nearly impossible to single handedly cut the entire strip without changing one’s feed hand position. Inevitably, slight wavering will result. This means some rather nasty saw marks, and a varying strip thickness. Routing the edges so that the bead and cove are perfectly centered across the thickness of the strip is impossible. Now mount that strip on the ribs. When mated to the previous strip, there will likely be thinner areas where it is impossible to have the strip lie tight against a rib, leaving an unsightly gap between the rib and the strip. Trying to fill these gaps takes a lot of time, work, and patience, and leaves behind telltale evidence of questionable craftsmanship. It is so much more pleasurable to take justifiable pride in good work than it is to take time to fix avoidable mistakes.
Cutting the Strips
The solution is to rough cut the strips slightly oversize and plane them to the final thickness. Either a band saw or table saw may be used. With the table saw, gang cutting of two or even three strips at a time is possible, given a saw of sufficient power. If two 71/4" diameter thin (1/16") kerf blades are substituted for the normal 1/8" kerf single 10" blade, two strips may be cut with the total kerf waste of a single strip cut with the larger blade. Since two of the smaller blades produce the same waste as the larger single blade, the power requirements are comparable. Three blades may be a stretch in a lesser-powered saw such as a tabletop model.
The strips are cut about 9/32" wide (thick) off the plank. They are then run through a planer to remove about 1/64" from one side, followed by taking the other side down to 0.250 ± a frog’s hair. Use a piece of scrap strip to adjust the planer – using an actual strip requires the entire strip to be run through, perhaps several times, and an incompletely thicknessed strip may later become mixed in with the finished strips. A planer with an adjustable thickness stop is a real help here, but careful adjustment and measurement can accomplish the same result in the absence of a stop. A dial vernier caliper is also quite useful when approaching the planer setting for the final thickness. This may all seem like a lot of work, and professional builders might scoff at the extra time required since time is money. Then there is the "too much waste" argument. The amount of extra time and waste is a mere pittance when the quality of both the strips and the boat are considered. Certainly a boat may be built with strips cut right off the saw. Inconsistencies in strip thickness can be easily faired out in a hull built without ribs, but in the classic ribbed guideboat, variations in strip thickness lead to the problems previously described. Acceptable sawn strips may be produced by a well-tuned saw, a sharp thin kerf blade or blades, long and rigid infeed and outfeed tables, and the capability to feed the plank tight against the fence for the entire length of the cut with no wavering. Not impossible, but not likely, either.
Many canoe and kayak builders prefer to use a band saw to cut strips, the reasoning being that since the strips are sanded extensively when on the hull, the wavy and/or rough surfaces on band-sawn strips will be sanded off any way. True enough. But the reason for making nice smooth uniform thickness strips lies in milling accurately centered bead and cove edges, which leads to a cleaner hull. The generation of less kerf waste when cut with a band saw is a non-issue, since planing off the saw marks generates waste comparable to that generated after cutting with a table saw. Band-sawn strips, when cut oversize and planed as described above, are perfectly acceptable, however.
Routing the Edges
If an accurately centered half round bead is cut on the edge of a precise 1/4" thick strip, that edge will fit perfectly into a recessed edge cut with a matching 1/4" cove bit. The ridge along the outside of the glue joint when such strips are mounted to the ribs will be quite small, requiring a minimum of scraping or sanding to bring fair. This accurate fit ensures a good glue joint with no gaps or voids. No gaps mean fewer fills. Fewer fills mean less work filling, scraping, and sanding.
The bead and cove router bits, sometimes called “canoe bits” by suppliers, are widely available for milling the edges, usually by mail or Internet order (See Appendix 6, Sources). They are virtually all made with 1/8" radii, or 1/4" diameters. Boat hulls are sometimes made with strips thicker or thinner than 1/4", but bits specifically sized for other thicknesses require special ordering. When buying bits, consider that a few thousand linear feet of cutting will be performed in making strips for a single boat. Bit quality considerations should take precedence over cost, and keeping the bits sharp is important but not difficult. Sharp bits cut cleanly, reduce tear out, and given the amount of cutting to be done, reduces strain on the router motor. A few passes over a medium to fine grit diamond sharpening stone on the inside flat surface of the cutters is sufficient.
The equipment setup for milling the strip edges is not difficult or complicated. A table mounted router, fence, and at least three feather boards are all that is necessary. Long infeed and outfeed tables are a luxury, the lack of which can be compensated for by proper handling during cutting.
Routing operations using a table-mounted router are nearly always performed by feeding the work against the rotation of the bit. Viewed from above, the router bit rotates counter clockwise and the stock is fed from the right to the left. The bit rotation tends to pull the stock into the bit, keeping the work against the fence. Strips may be milled in this fashion, but significant tear-out can result when the grain changes slope. Cedar is not very strong between grain lines and will crack or tear out, especially while cutting the more fragile cove edges. Back routing, sometimes called climb cutting, reduces tear-out to nearly zero and produces a superior quality milled edge. In this method, the work piece is fed with the rotation of the bit. Back routing with a hand held router is extremely difficult to control, with the router suddenly wandering off line, potentially ruining the work. In a router table, back routing can grab the work piece and propel it with near rifle-like force. However - when properly set up and carefully executed, back routing is quite safe and will produce nearly perfect bead and cove strips regardless of changes in grain orientation. For back routing strips, the feather boards are adjusted to keep the stock firmly against both the table and the fence. When fed into the cutter, there is no tendency for the bit to grab. In fact, the stock must be pushed or pulled through the entire length, with full control.
Cutting the Bead
Before beginning the edge milling, set two strips aside. These can be damaged or low quality poor color strips, and need not have any edge treatment. They must be full length since they will be used as alignment battens for the ribs, and later as anchors for the bungee cords used for clamping the actual glued strips. They will ultimately be discarded and not become any part of the boat.
The bead edge is cut first so that the beaded edge will then bear against the feather board when the coves are cut. If the cove edges were cut first, the pressure of the feather board against the fragile cove edges would damage them. The bead bit is installed in the router and its height adjusted visually so that there is a smooth transition between the surface of the table and the curve of the cutter. This adjustment is later refined using a short piece of actual strip to be milled. The fence is then adjusted so that the apex of the curve is tangent to the fence. Again, further refinement will be done.
Now place a piece of strip against the fence so that it spans the cutter, and long enough to extend at least a foot on either side. The cutting edge will have to be rotated out of the cutting position so that the strip will lie against the fence on both sides of the bit. Place one feather board flat on the table to bear against the strip, centered at the cutter and pushing the strip against the fence. Place the other two feather boards vertically against the fence so that they push down on the strip. These should be located just before and just after the cutter opening in the fence. See Figure 8-2.
Figure 8-2. Router setup for back routing bead and cove edges.
With the power off on the router, push the test piece through the feather boards. It should be a snug fit, and require some effort to pull it back out. Check the feather boards, making sure they are not cocked against the strip and all of the teeth are bearing against the strip. Remove the test piece and turn on the router. Feed a few inches of the strip into the cutter, holding it securely. If there is any tendency for the strip to move on its own, stop and readjust the feather boards to provide more pressure. The ideal adjustment is achieved when the strip must be pushed into the rotating cutter, and will not move when you let go of it.
Examine the short test piece. The bead should be centered, with no shoulder. If any shoulder is apparent, adjust the vertical height of the bit to correct it. The top of the bead should be round and in alignment with the flat uncut portion. There should be no flat area on the top of the bead(2). If there is a flat, the fence must be moved back so that the bit cuts deeper. If the bead is below the level of the uncut edge, too much stock is being removed and the fence must be moved forward. Bead cutting problems are illustrated in Figure 8-3.
Figure 8-3. Bead cutting problems.
With the router and feather boards properly adjusted, turn on the router and feed a strip into the cutter. When about two or three feet have passed the outfeed edge of the router table, change your position to pull the rest of the strip through. Keep the strip level with the table as you pull it, using one hand between the outfeed feather board and the edge of the table to keep the strip flat on the table, and letting the finished end fall to the floor. If you push the entire strip through with no outfeed table or other means for maintaining the strip level, the flexing of the strip as it drops to the floor will lift it off the surface of the table slightly, even against the pressure of the feather board. The result is a bead that is not centered, and all the setup and test runs will have been wasted. Be careful sliding your hand along the strip to gain a new grip. Slivers are possible, and can be surprisingly painful. Leather work gloves work well here.
All of the beads should be cut once the router is set up simply as a matter of convenience. It takes time and patience, with several test cuts, to get the fence, feather boards, and router working in harmony. Changing to cove cutting is best left until all of the beads have been cut.
Some builders prefer to keep the strips in the natural order as they were cut from the plank. This permits book-matching strips on each side of the boat, eliminating the need to sort through a pile of randomly stored strips to select one of just the right color. This approach works well for strips that are naturally full length, but it becomes increasingly difficult to maintain the order when shorter strips are scarfed together to provide the needed length. We know of at least one professional builder who mills his strips, then sorts and arranges them side by side on a very long and wide table. The final color matching and strip layout for the entire boat is thus achieved, and handling the strips after this initial sorting is minimized. The strips are then mounted on the hull in the sorted order. Certainly this is a refinement that requires an amount of open space not likely to be found in the average amateur builder’s shop.
Cutting the Cove
The setup for cutting coves is the same as for cutting the beads, with the obvious exception of the router bit. Once the bit is changed, the adjustments of the bit height, fence location, and feather boards are the same as for bead cutting. Test pieces are run on strips with the beads already cut. The ideal cove is centered on the strip and has very small but perceptible flats about 10 mils wide on the edges. These dull edges will be less fragile than if the cove is cut deep enough to form a knife-edge.
Variations for cutting coves have been noted among some builders, both amateur and professional. One recommendation is to cut the coves shallow, leaving a significant thickness on the edges. This excess must later be faired off, reducing hull thickness. This is an impossible job on the inside of a guideboat, given the interference of the ribs. Another recommendation is to cut the strips initially thicker than 1/4" so that when the coves are cut to the proper depth, the additional thickness will leave a flat on the cove edges. The problem here is strips that are thicker than a precise 1/4" will have shoulders left when the beads are cut. Both of these alternate milling methods may be acceptable for kayak construction where the inside of the craft is not seen, or to canoes where the absence of ribs easily permits proper fairing. For guideboat construction, cove edges that resemble the edge of a very dull knife will be sufficiently sturdy to resist breakage under careful handling conditions, while still permitting reasonable ease of fairing both the inside and outside of the hull.
Before cutting the coves, set two beaded strips aside. These should be full-length good quality strips, to later be mounted as the sheer strips. A cove on these strips is not necessary; in fact, it is not recommended. The boat will be stripped with the beaded edges up from the sheer to the bottom board, and the sheer strip will see a lot of epoxy drips when the outside of the hull is fiberglassed. Having a coved sheer edge complicates the clean up and may compromise the design location of the sheer.
Once all of the adjustments have been made, run a full strip through and verify the quality of the cove. Potential problems are shown in Figure 8-4.
Figure 8-4. Cove cutting problems.
When pulling the strip through the router, be very careful handling it. Grip the center portion of the strip with your thumb and fingertips to prevent putting pressure on the cove edges and possibly cracking them. When the milling is complete, carefully lay the completed strip safely aside off the floor on a bench, across sawhorses, or on some other safe storage support.
Some shops use two routers set up to simultaneously cut the bead and cove edges. The advantage is a savings in time, but at the expense of requiring a more extensive set up and double the noise intensity. A dedicated router table is required, and once set up and adjusted, is used for no other purpose. Unless building multiple boats is planned, such a facility is not required.
Occasionally, back routing will lift a grain line from the strip without tearing it out. The nearly straight grain in red cedar with the weaker soft wood between grain lines is largely to blame, but dull bits exacerbate the effect. These strings can be removed, but do not try to pull them off, since they will only get longer and can potentially split the strip. Clip or break them off, or, if short, leave them alone. They will be buried in the joint, and do not cause any further problems.
1 Appendix 4 details the technique used to scarf the shorter strips together.
2 Some builders mistakenly leave a flat on the top of the bead to act as a glue reservoir. This can cause glue creep when the boat is exposed to the hot summer sun, which leads to unsightly fiberglass print through. Such excess glue is also a weaker joint than one that is properly fitted and glued.