Building a Cedar Strip Canoe: The Details: Making the Stems
Stems are laminated strips of wood that form the tip of the stern and bow. The inner stems are where the ends of the strips are stapled and glued, and tie the stripped hull together. The outer stems are glued on top to the inner stems and blended into the stripped hull with planes and sandpaper. They are usually made of hardwood and provide some protection for the soft strips and inner stems from collisions with shoreline obstacles. For this canoe I made the inner stems with three ¼” strips, two cedar and one white pine. The outer stems were made with three ¼” strips, the out most being maple and the others white pine.
The stem strips must be steamed and clamped to the bow and stern forms and allowed to dry. Steaming the stems can seem a bit intimidating at first. I made a steamer out of a length of 4” PVC pipe and plugged the ends with a pieces of ¾’ particle board cut to fit with a hole saw. The bottom plug had a hole drilled in it to allow steam to enter the pipe. The source of steam was an old coffee pot with a short length of copper pipe replacing the bubbler. I filled the pot with water and set it atop a Coleman single burner backpacking stove. Once I had soaked the stem strips overnight in water I placed them in the PVC pipe, plugged the end and hung it from the rafters of my garage so that the pipe on the top of the coffee pot enter the hole in the plug. The secret to successful steam bending is lots of steam. I cranked the control of the stove all the way up to get the water boiling furiously. When I saw steam shooting from a tiny hole at the top of the PVC then I knew the steam volume was about right. About 30 -45 minutes is about right. The sides of the pipe will start to get soft.
The hot strips, all 6 of them are clamped onto the forms. Here is where I made a mistake with the forms. I only cut 6 2” round holes in the forms I should have made them 1-1/2” and spaced them closer. Also I should have cut the first hole near the sharpest bend in the stems so that I could clamp the strips there first. This would have put less stress on the strips when bent since the ends have less distance to the form. I made it work.
Once the strips have been thoroughly dried, I glued them together and clamped them back on the forms. I used a mixture of epoxy, sanding dust and bits of fiberglass for the glue. The for edge was first covered with plastic packing tape to prevent the strips from becoming permanently attached to the form. Packing tape was also used between the 3 inner stem group of strips and the 3 outer stem group of strips. This is a messy job and it is difficult to get all the strips aligned.
After the epoxy glue mixture was sufficiently set I removed the clamps and cleaned off the dried excess glue with a sureform plane. The outer stems are set aside for later and the inner stems are put back on the stem form which was reattached to the strong back table with the rest of the forms. I attached one end of each stem to the form it butts against with a screw through the form into the stem and the other end with a screw throught the stem into the stem form. The stem must be now shaped. A center guideline is drawn the length of the stem, and a line 1/8” to the left and right of it are also drawn. Using a plane, spoke shave, sureform plane or all three, the stem is shaped to allow a glue and staple surface that will be flat with the strips being attached. Between the lines is where a flat is left after the shaping is finished. Near the top of the bow or stern the angle is sharper. The stem to strip interface should be as flat as possible to allow plenty of area for the surfaces to make contact.
I found that my bow stem form was off a little and I raised one end of the inner stem with a shim. I will continue to make small adjustments like this as the build progresses. It’s just part of building when you are neither an artist or carpenter, just one determined to build a useable canoe.
More links to building details
- Building a Cedar Strip Canoe: The Basics
A practical account of my experiences and a brief guide to building a cedar strip canoe. It includes links to stories of using the canoe for wilderness camping and fishing.
- Building a Cedar Strip Canoe: The Details: Lofting the Plans
A description of how to create canoe plans from a table of offsets which are hull measurements. Lofting. Expansion of "Building a Cedar Strip Canoe: The Basics". More details this time.
- Building a Cedar Strip Canoe: The Details: A Guide to Making the Forms
A description of how to create the a jig for making a stip canoe. Making the Forms. Expansion of "Building a Cedar Strip Canoe: The Basics". More details this time.
- Building a Cedar Strip Canoe: The Details: Cutting and Milling the Strips
A description of how cut and mill the strips. Expansion of "Building a Cedar Strip Canoe: The Basics". More details this time.
- Building a Cedar Strip Canoe: The Details: Stripping the Hull
A description of how to attach the strips. Expansion of "Building a Cedar Strip Canoe: The Basics". More details this time.
- Building a Cedar Strip Canoe: The Details: Sanding and Fiberglassing
A description of how shape and sand the hull then apply fiberglass and epoxy. Expansion of "Building a Cedar Strip Canoe: The Basics". More details this time.
- Building a Cedar Strip Canoe: The Details: Seats, Gunnels, Decks and Yoke
A description of how make the seats, yoke, gunnels and decks. Expansion of "Building a Cedar Strip Canoe: The Basics". More details this time.
- Building a Cedar Strip Canoe: The Details: Final Steps
The final steps and results of my second cedar strip canoe build.