Posted on October 16 2015
A customer wrote in recently with the question, "Do you prefer MDF or plywood for the forms and the strongback?" The answer once again comes courtesy of the redoubtable Ron Frenette.
This customer was tall, so he added it was important that he build a long canoe with plenty of legroom. Ron replied, "If you construct a 16 foot strongback, it then becomes possible to build any 15 or 16 or 17 foot canoe on the same unit.
That said, I would suggest that the ‘footprint’ space in your garage be a minimum of 9 feet wide and 20 feet long. That will provide working/walking/leaning space for whichever project you choose."
With the workspace set up and the model chosen, Ron turned to the plywood versus MDF question. In his workshop, "we tried using 5/8” MDF because the CNC machine cuts such a clean edge in the sheet. However, the staples really are hard on the material and often cause ‘flaking’ off of segments all along the edge.
So, we use 5/8” medium density particleboard; it is not as clean as MDF but the staples do not do damage.
One of our colleagues bought a set of CNC molds for a Prospector some years ago; he is currently building canoe # 24 on the same molds."
For more supplementary information, check out Ron's article on constructing a strongback from manufactured I-beams.
We offer CNC small boat molds, available here.