Wednesday, 13 April 2011

Reactions Feedback.

The new reactions boxes on the posts have resulted in a few 'explain more' marks.
I havn't looked back through every post but I noticed the heat bending and leatherwork posts had been checked.
I'll post some more pics on both these topics soon, but here's some more heat bending info'.
With the heat bending it's used to get the bow limbs roughly straight and symetrical which makes tillering simpler and allows me to use stave which would otherwise be unuseable.
Steam or heat gun works as the heat source, the big advantage of a heatgun is it can be done while the bow is clamped on the jig, the advantage of steam is it heats a larger area more venly.
Once the wood is at 100 degrees C or above it becomes pliable. With the heat gun, I set it to 250C and keep it about 3/4" from the area to be bent for about an hour. The wood needs to stay in its jig for a few days to stop it moving back. There is about 10-15% over bend needed, E.G If you want a 100mm bend then you need to bend it on the jig to 115mm as there is some spring back.
I try to avoid bending the wood too much before it's heated up to avoid over stressing it, so I'll heat it for 15-20 mins and then bend it and put in pegs/clambs etc to hold it in position.
If you want to try heat bending it can be quite a surprise how bendy the wood becomes, try it with a bit of scrap wood.

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