Red Maple MH Style Board Bow

[Lumberman]

Well I only had to do a quadruple take but it finally began to make sense to me. Thanks for taking the time to spell it out!

[PlanB]

Glad it's more understandable. I've added nocks and thinned the limbs down some, but no tillering yet. It's still losing about 10 grams a day in moisture on a total weight of 900 grams. Winter time R.H. in the house right now is 30%.

So, not much else I can do on this bow -- it's just going to have to be a waiting game until the weight stabilizes.

[bradsmith2010]

if it is 30% in the house, the bow may go to 6%,, which might be a little low,,,

[PlanB]

You're right Brad, I'm going to move it outside on the porch.

We're in a cold snap now, so RH is really low in the house but it should be warming a little middle of next week. I'll keep an eye on the RH where the bow is.

[PlanB]

Just wanted to finish this thread off even though the bow handle experiment failed.

A check of weight showed the bow gained 5 grams outside the first day, then zero grams for two days after that, so I brought it inside and continued work on it.  I asked my wife to take a tillering pic of the bow so I could see it when I first started working on it after bracing. It's now the only photo of the bow intact. (Bottom pic).

I continued tillering, and I eventually had it short drawing to 50# and even tried it outside for a dozen arrows or so. But on the tree when just short of full draw (27") I heard the infamous "tick". I checked over the bow, and couldn't see any cracks in the wood or splinters. There were none.What I didn't notice was that the handle backing strip was likely split across in between two of the bands.

I put the bow on the tree again and drew it (it's a rope and pulley rig), and I could see one limb pulling well out of balance with the other one. I could tell the bow was a gonner, then, so I pulled it to full draw to see whether the crack would show or the bow break. After two pulls It let go hard at the handle.

Looking at the damage,  I'm thinking that the backing at the handle's sharpest bend let go first -- the tick I heard. In hindsight, the flax was much too thin (really paper thin) and not wide enough, either. I should have put it down in two or three layers, but being new to flax (and backing, in general) I'd only put down a thin narrow strip.

Then when flexing the wood, with no reinforcing, the bow broke between the two bands at the steepest part of the grain, and the crack instantly propagated back through the bands.  They snapped, one after the other, and the limb separated off.






While the reinforcing experiment was a failure, I think it probably would have worked if I had used a thicker backing. Or if instead of individual bands, the wrapping around had been continuous over the sharpest bend of the handle. Though that wouldn't have looked as much like the original bow with it's band and diagonal reinforcement on the limbs.

I don't think I'll try another Meare Heath soon -- I  the weight and feel of the bow wasn't great. Though it wasn't finished yet, It weighed nearly two pounds, and was pretty unwieldy to maneuver in the house. It's was more of a novelty to try. I did really want to see what kind of arrow speed it might have had, just to compare it with other reproductions, but didn't get a chance with a finished bow. If I ever do one again, I think I'll try an even lighter wood than red maple, and better backing of the handle.

Anyway, that's the post mortem. I think it came close. And I know more about flax reinforcing and some of what a real Meare Heath must have felt like like to heft and shoot.

[bradsmith2010]

thanks for the info,,very nice try on that one,,

[Stixnstones]

You only fail if you dont try. Excited to see how this goes. \m/

[willie]

Sorry that blew on you, I liked the creative thinking tho..

btw, other than the flax/tbb3 matrix not being thick enough, would you use that combo again? are the left over pieces brittle, or does the tb3 seem to have enough flexibility? Did the flax delam under tension?

[Lumberman]

Bummer! Thanks for sharing the whole experiment though

[Stick Bender]

Ooch sorry it look so nice !

[TimPotter]

"Looking at the damage,  I'm thinking that the backing at the handle's sharpest bend let go first -- the tick I heard. In hindsight, the flax was much too thin (really paper thin) and not wide enough, either. I should have put it down in two or three layers, but being new to flax (and backing, in general) I'd only put down a thin narrow strip."

I was enjoying this thread. I am currently working on the same thing only using sweetgum, but opted to not worry about doing the all out set back handle. Maybe rawhide applied wet would have been a better solution, but who's to say. At least you went for it. Thanks for sharing your experience.

[PlanB]

Brad Stix Lumberman, thanks, guys!

Willie in answer to your question, I would try flax and tb3 again in some area of special need. It definitely didn't delaminate first, but broke across the backing first. It was under tension, which tends to pull it down into the wood, instead of away from it. The break shows it broke across right at the edge of the upper band.

If the backing had been thicker, I don't think it would have happened, and/or if the circular reinforcement had covered the area, I also think it could have held. Tb3 seemed and still does seem flexible, but long term, I don't know. My guess is, it will stay flexible enough, but no proof.

Tim, I think rawhide might have worked well or better if you had a good way of dealing with the ends. Maybe it would have to wrap around more than once. I haven't used rawhide yet, so I don't really know.

Today I looked at the broken pieces and thought why not use it as a test bed, still? Just epoxy that break back together (I used W.E.S.T epoxy) and then try more flax positioned as mentioned to reinforce the handle.

Worst that could happen is it breaks again, either at the new glue line, or elsewhere in the grain violated wood, as before. I know epoxy doesn't make it a primitive bow, exactly. I don't really care about that for a simple test. And it's just applied to the break surfaces,  so I'm thinking a repaired bow will still be a good test of flax reinforcement. Maybe even harder a test.

[willie]

Just epoxy that break back together (I used W.E.S.T epoxy) and then try more flax positioned as mentioned to reinforce the handle

sounds like a good...... PlanB

sorry I did not ask that delam question well......................what I meant to ask was....

Did the flax fibers seem to delaminate from the tb3?  With the low stretch flax I might guess that individual flax fibers reached their breaking points sequentially, before getting to stretch much and act as a bundle with the other fibers. with a stretchier binder glue, the bundle might perform different

[DC]

The first thing I can remember that my father taught me was never depend on "cross grain" (his words). It will let you down every time. You are to be commended on your perseverance though. And the fact that you posted the failure. Too many times these post just fade out and nobody learns anything.

[PlanB]

DC agreed! And of course, I knew that going in, since the historical bow had it. Plus it was broken.

I would add that it won't always let you down if reinforced with some other material in the cross grain tension direction -- which also has an ancient tradition. Lashing, laminating, banding with fibers, hides and metals, doweling, pinning, through-bolting and drifting with drift rod and other methods have all been used historically to take up wood cross grain tension, and still are in use today.

Since the Meare Heath bow used banding on the limbs, it seemed like a good experiment to see if it might have worked on the handle as well.

Glad to report the last failure in case it's useful or interesting, and I'll probably need to again. 

Willie, no the flax and glue stayed together quite sound, in fact on the side bands it looked like somebody cut across the grain along the cracked wood with an X-acto knife -- very little detectable fiber separation at all. I bet it's a lot better bond,as a matrix than glass fiber and polyester resin. In fact I'm certain of it, having seen plenty of those fractures.

I did see air entrapment/glue starvation in the bands when I tried to remove them -- that's because they were wrapped and saturated several layers at once. The backing strip was only one layer thick and looked perfect. So the lesson is, only one layer at a time, let dry, then add another layer, to build thickness.

btw the rings are proving difficult to peel off. Really good adhesion to the wood. They are going to have to be sanded off.