cutting molds

[Erik]

hi all,
i am cutting my molds tomorow night, and i have a question.

when i was into canadian canoes, i noticed that the molds were not only cut out to shape, but the edge of the mold, where the planking will attach had an angle to it. when i read canoe craft, it doesnt mention this angled edge. is this optional? does it help much to create a nicer bend in the cedar strips?

i will be cutting these at a fully furnished wood shop, so the angle is not likely a problem to create, but the plans dont show the angles, and i immagine that each station has a different angle, and the angle on each station must change from shearline to keeline... right?

thanks!

[Glen Smith]

This process is called "fairing the molds" and it is not really necessary especially if the molds will be used for the building of just one boat. When the mold edges are left square, each mold is installed on the strongback so that the reference edge (where the strips will touch) is the edge facing the nearest end of the boat. The back face of the mold does not touch the strips. When the molds are faired, you remove material from the face nearest the end of the boat so the reference face becomes the face that is nearest the center of the boat. The molds must be installed on the strongback according to this rear face instead of the front face. Each mold edge is planed and sanded so that the strips lay flat against the entire surface of the mold edge and form a fair line all along the boat.

The only "problem" I run into when using square-edged molds is that the sharp edge can marr the inside strip surface if the strips are forced hard against the molds using wedges during staple-less construction. Some builders use a small radius piloted router bit to slighlty round over this sharp edge to alleviate this problem.

[Bud]

Thanks Glen, the sharp edge on the end molds marks my strips and leads to more sanding. Why didn't I think to round the edge? :oops: :roll:
Gotta love this forum! 8)
Bud

[Glen Smith]

Bud, that sharp edge is actually the mold's reference line for a "fair" hull so be careful to not remove too much material or the result will be the equivalent of having cut out an undersized mold. Just slightly round over the edge. This can even be done with sandpaper.

[Erik]

Thanks! i will cut square and round off corner just slightly. this sounds better.

by the way Glen, i was in Baie-st-paul last winter... what a great spot! we are planning on heading back up there this winter (little snowmobiling trip)!

[Glen Smith]

Hi Erik, if you come back this winter, send me an email first and I will give you my phone number. Maybe we can chat about boats between your snowmobile rides.

[Erik]

will do!! ill find out where you are at and see if the trail swings by your place. we can plan a days trip around it.

[Erik, Belgium]

hi Erik,

here is a picture of it.
It is no big deal to round the edges, but has some advantages, like Glen explained.

Erik, Belgium

[Bernie in Illinois]

To Erik, Belgium
Your molds are a work of art! People tell me I'm a perfectionist, now I know they are wrong. I made my molds as inexpensive and simple as possible without jeaperdising accuracy, or in any way affecting the purpose for which they served. That's it, nothing fancy.