This last tillering has got the string shortened to a low brace height (about 2-3") and the bow drawing back to about 22" at 32 pounds so it's getting close. The bow had taken a tiny bit of set, so I've clamped it anto a length of 2x2 with a bit of 1/4" ply under the grip whilst heat treating it this time just to encourage it to stay pretty straight.
It will be interesting to see how much set it has in the finished bow, hopefull less than my non-heat treated Hazel bow.
I just thought, I'm making the grip assymetric and right handed...I hope the guy it's for is right handed!!There's still time to adjust it, let's hope he reads this!
The pic shows it's begining to look like a bow, I've dtrung it, but it needs another day or so before I draw it after the heat treatment.
can you please describe me process of heat treating?? thanks
ReplyDeleteHi,
ReplyDeleteHeat treating is a matter of slowly heating the wood (on the belly)to a golden brown, it needs to be done slowly rather than just scorching the surface of the wood (which was my mistake when I first tried it).
This post http://bowyersdiary.blogspot.co.uk/2012/09/multitasking.html shows a picture of it being done.
It takes about 30-45 minutes for each limb and the bow needs to rest for about 3 days afterwards to re-hydrate. When you first apply the heat it seems that nothing is happening for 10 to 15 minutes, then you slowly notice a slight colour change. As you move the heat gun along the process speeds up a bit as the wood has started to warm up. The Traditional Bowyers Bible volume 4 has a section on it.
I bought a temperature controlled hot air gun to do some experiments, and I found that anything over 250C would slowly brown the wood but about 300C worked well. Take care not to scorch to wood. A kitchen timer set to alarm after 5 or 6 minutes is useful for reminding you to ceck it and move the heat gun along by an inch or two.
Derek thank you! I found your reply very useful! greetings from Serbia
ReplyDelete