Saturday 23 February 2013

Feel the Heat


There are flecks of snow falling, so more heat treating and bending is about the only sensible job in the garage.
I've done the other limb of the longbow stave which is looking good .
While the first limb was clamped up yesterday I tidied up some of  my Yew, I ran one half log through the band saw taking off the manky side as a long triangular offcut. I always look at the offcuts and save anything useful.
This piece was almost the size of a bow but it had some bad deer damage through the sapwood, nasty knots and some very skinny parts (2nd pic)
It seemed to be challenging me to turn it into a bow. I couldn't resist and quickly shaped it with bandsaw and spokeshave. I flexed it a bit and there were horrible cracking noises as the bark started to pop off.
Well I couldn't resist I de-barked it and saw the extent of the deer damage. I did a sapwood back patch on it  and this morning while the 2nd limb of the longbow is resting after heat bending I've narrowed the grip and heat bent that to bring the tips in line.
I'm just going at it  mad to see if I can getting shooting for the club 'end of month' shoot tomorrow. I'm calling it the bonkers bow, it' just a bit of a joke to see if I can bully a bit of Yew into a bow in revenge for that one whacking me on the head.
Not sure if it's the bow or me that's bonkers.

The last pic shows it cleaned up ready for the sapwood back patch, that last pocket of rot was cleaned out and filled with sawdust-Epoxy mix before the patch was glued on.

Update:- I've done a belly patch on one skinny area, I suspected it was going to be weak and as I pulled it back on the tiller I could see some remaining cambium (the brownish red under bark layer between the bark and the creamy white sapwood) popping off as the weak spot flexed. The flexing also made 3 knots start to come out. That was rather reassuring as it shows my usual caution with knots is well justified.
I've filled 2 of the knots, the 3rd will have to wait, so I can't get it shooting for tomorrow. I think it may have the makings of an interesting character bow.
Where the belly is rather triangular from the way it was sawed, I've sort of echoed that shape along the bow. It will be interesting to try a different belly shape. There are some South American native bows which are the same proportion as a longbow but with a much more triangular cross section and a back which is actually concave. This bow has a concave back in some places so maybe I'll accentuate that.
I can't decide whether to shoot Twister of one of my Longbows tomorrow, maybe I'll give my side nocked longbow an outing.

4 comments:

  1. Interesting stuff! I'd be really interested to know how you do your heat bending.

    Do you clamp the bow down into the desired shape first, then essentially heat-treat the belly, or do you heat while letting gravity/added weights pull the bow gently into shape?

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  2. It depends on exactly what I want to do.
    Sometimes I use steam, sometimes dry heat.
    I usually jig it up working out where it will be clamped, but don't actually put it under any real force until it's hot. Often I'll apply a bit of tension early with some rubber strapping, but I've also done the 'tie a brick on it and wait until it starts to move' trick :)
    I did a video a while back of some steam bending. Try the search top left of the page. It actually works better than most search facilities.
    (I just checked a search on the blog for 'steam bending' brings up 3 or 4 post, the bottom one has the vid).

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  3. Hi Derek, Could you explain how you do the patching? Both belly and back. Thanks
    BTW, I always enjoy your posts. Here and on PA.

    Thanks,

    Jpitts (PA)

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  4. Hi, The 'search' on the blog is pretty good. if you search for 'patching' it brings up one post.
    'repair work' brings up another.
    You may need to look at the other posts around those to get the full story.

    I just flatten the area in question or make it flat in one plane and slightly curved in the other (like a flexed steel rule). Belt sander with coarse belt is good for this, but a rasp will do it too.
    I try to make the patch from an off-cut of the same wood and fiddle around with it to get a good fit. (Often it takes a couple of tries to get the patch the right size shape and fit).
    Generally I try to get the patch thin enough to flex a bit so it will get a good fit. I score both surfaces with the edge of a rasp. Glue 'em together held with masking tape to maintain position then bound with 1" rubber strap (usually 2 layers).
    Once it's strapped up, I flex it a tad to help it seat. Don't overdo the flexing, and don't clamp too hard and squeeze out all the glue.
    I use Resintite glue which I also used for gluing up a bamboo backed yew bow.

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