pre bent cores

[oliver]

What a great forum. I pressed my first skis this weekend and wanted to thank everyone who was willing to share the benefit of their knowledge and experience. I build cedar strip kayaks and find that prebending strips by heating them for a few seconds with a heat gun makes creating compound or difficult curves easier. I tried the same technigue with my poplar and ash cores and it worked well. Maybe some of you are already doing this but I haven't seen any posts about it so I thought I would share. For a more detailed description do a search on Laughing Loon kayaks. Rob Macks has a building tips page that describes it well.

[plywood]

Use a heat gun to apply dry heat to bend and twist strips into place instead of relying on force.

A heat gun boils the water in the wood to bend without having to wet the wood. This allows you to glue immediately without having to wait for wood to dry as you would it you used a wet/steam heat method.

The heat gun applies local heat to a small area so you don't need a large box or other apparatus. There is no waiting, no spring-back as in wet bending.

Northern white cedar is the best wood to utilize the heat gun method of bending for the already stated natural bending properties. But also, because NWC is typically air dried, the natural glue (lignin) which holds the wood fibers together can be reactivated by heat. Kiln drying wood alters the lignin and it will not respond as well to heat/steam bending.

well, sounds interesting! i`ll try this for my core, even if there are only 2 sheets of 1,5mm ash at tip and tail. i`m really curious if this works! thanks for the idea with the heat gun!

[Rich C]

I do this with my cores. I notice less initial relaxation in the camber and so far my boards seem to hold their camber better over time than the ones where I didn't pre-bend the cores.