Wednesday, 26 September 2018

Crossbow Limb Glue Up

I got the clear glass laminations and EA40 epoxy from 1066archery shop
I did the glue up very carefully as the laminations can slip and move as clamps are applied. You can never have too many clamps but even so it's a relief when they are removed and the masking tape taken off the glass and you can see if the glue line is good (it's clear glass).
It grieves me deeply when I see people gluing up laminated bows with great gaps between the clamps... if you don't have enough and can't afford more, scrounge some old inner tubes and use rubber strapping between the clamps. It's daft to scrimp on the early stages, a bit like building a house but not using any cement between the blocks in the foundation.

Once cured I took off the clamps and peeled off the masking tape which I'd applied to protect the glass. The glue up looks great, I was amazed how clear the glue and glass was, it just looks like polished maple... which reminds me of one guy on FB who got upset when I laughed at his indignant claim that his bow was Yew when it was a Yew core with clear glass laminations on back and belly, he didn't like me calling it a glass bow, but it's the glass that's doing all the work, ok, some core woods are better than others, but a glass faced Yew bow ... isn't a "Yew bow".

I've run the first limb through the bandsaw to put a slight taper on it, sawing away the lower edge and leaving the top edge straight. I clamped it up in the vice and gave it a gentle flex, it seems suitably stiff, but it's all guess work.
I tried a bend test on the triangular off-cut, clamping it in the vice... blimey, it bent a hell of a way back and showed no sign of breaking, it seemed to recover too, which is very encouraging!
(Note:- I put masking tape on the limb for sawing, to protect the faces)

Meanwhile, I took a sunny stroll over to the woods where they have been opening up a corridor alongside the brook, to let more light in and promote some young growth. There is a great variety of trees and some had been cut and roughly piled as a dead hedge. I looked in it for some curved timber to make levers/siyahs for the Elder primitive. I found a couple of bits, but I'm not sure if the lighter stuff is Willow or Ash. Willow is
rated as useless for bows, but seeing as how the siyahs just want to be light and stiff, it might be suitable. Anyhow, they will not be long levers. I found three pieces and suspect I have Ash, Willow and Blackthorn. I've reduced the wood substantially so it can be seasoned quickly on a radiator and tested to see if it is tough enough.

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