Author Topic: Chrysal or crack  (Read 15414 times)

0 Members and 1 Guest are viewing this topic.

Offline PatM

  • Member
  • Posts: 6,737
Re: Chrysal or crack
« Reply #30 on: February 26, 2015, 01:19:02 pm »
I just mentioned multiple layers so that you could avoid having to heat bend a single layer. If you have a woodworking store that sells veneer scraps you can use those with little prep work.

Offline DC

  • Member
  • Posts: 10,396
Re: Chrysal or crack
« Reply #31 on: February 26, 2015, 01:28:52 pm »
The tips and arrow pass are what was sold to me as Brazilian Walnut. I'll try and match that. At least in color.

Offline mwosborn

  • Member
  • Posts: 806
  • Mitch Osborn
Re: Chrysal or crack
« Reply #32 on: February 26, 2015, 06:24:43 pm »
Here is a picture of a chrysal on one of the first bows I made as a comparison.  It looked to me like the "crack" was below the area that you recurved.  Could be a crack - but if it below where you recurved the tip, you can't feel it, and it doesn't open up when you stress it, I am sticking with chrysal.  BWTH do I know?   ???

That's not a chrysal either ;)

That's a crack.  Chrysals always run diagonally because of what they are, and are always lighter in colour.  They also don't wiggle about and zig zag like that.  Both images are cracks, not chrysals.

Thanks for the lesson!  Always learning   ;D
Enjoy the hunt!  Mitch

Offline Marc St Louis

  • Administrator
  • Member
  • Posts: 7,877
  • Keep it flexible
    • Marc's Bows and Arrows
Re: Chrysal or crack
« Reply #33 on: February 26, 2015, 06:56:09 pm »
Most likely a crack and unfortunately it looks like the bow is working at that point so the glue won't work.  You would be better to do as Pat says and to use an elastic wood
Home of heat-treating, Corbeil, On.  Canada

Marc@Ironwoodbowyer.com

Offline Springbuck

  • Member
  • Posts: 1,545
Re: Chrysal or crack
« Reply #34 on: February 26, 2015, 07:10:11 pm »
Most likely a crack and unfortunately it looks like the bow is working at that point so the glue won't work.  You would be better to do as Pat says and to use an elastic wood


This is a good question.  I might have assumed it wasn't working, or wasn't working much there.  My answer was based on assuming that this was a static or barely working recurve.  Just glue, or too thin a laminate here is not going to fix it well.  So, I guess you can make it static, but that takes out a lot of working limb.  Hmmmmmm....

Offline PatM

  • Member
  • Posts: 6,737
Re: Chrysal or crack
« Reply #35 on: February 26, 2015, 08:06:27 pm »
You can use a long feathered out laminate in a working area safely.  You're just mimicking putting down a few extra growth rings.
 Here's a pic of a belly laminate covering a v-splice that feathers well out into the working limb.

Offline Marc St Louis

  • Administrator
  • Member
  • Posts: 7,877
  • Keep it flexible
    • Marc's Bows and Arrows
Re: Chrysal or crack
« Reply #36 on: February 26, 2015, 08:42:03 pm »
Most likely a crack and unfortunately it looks like the bow is working at that point so the glue won't work.  You would be better to do as Pat says and to use an elastic wood


This is a good question.  I might have assumed it wasn't working, or wasn't working much there.  My answer was based on assuming that this was a static or barely working recurve.  Just glue, or too thin a laminate here is not going to fix it well.  So, I guess you can make it static, but that takes out a lot of working limb.  Hmmmmmm....

It is a dilemma.  As I said, I don't believe crazy glue will work, it never has for me in the past.  It just doesn't have the compression strength of wood or the elasticity.  It may be a static but that section of the limb seems to be working a bit to me.
Home of heat-treating, Corbeil, On.  Canada

Marc@Ironwoodbowyer.com

Offline DC

  • Member
  • Posts: 10,396
Re: Chrysal or crack
« Reply #37 on: February 26, 2015, 09:01:22 pm »
I have steam bent underlays? of Peruvian Walnut(it wasn't Brazilian) and will start to fix them in a few days. I found a Hardwood Distributors Association Webside and it says this about Peruvian Walnut

"Physical Properties: Medium bending strength and resistance to shock loads. High crush strength and low stiffness. Very good steam bending characteristics. A compact, elastic wood with good strength properties."

Sounded like what I was looking for and they are right about steaming. I like low, medium and high instead of a bunch of numbers.

Offline PatM

  • Member
  • Posts: 6,737
Re: Chrysal or crack
« Reply #38 on: February 26, 2015, 09:05:40 pm »
Peruvian Walnut is one of the only "tropical" woods that actually is what its name suggests  rather than just being named for appearing like a more well known wood.

Offline DC

  • Member
  • Posts: 10,396
Re: Chrysal or crack
« Reply #39 on: February 26, 2015, 09:06:48 pm »
The dust sure gets up my nose.

Offline joachimM

  • Member
  • Posts: 675
  • Good - better - broken
Re: Chrysal or crack
« Reply #40 on: February 27, 2015, 12:13:51 pm »
You can use a long feathered out laminate in a working area safely.  You're just mimicking putting down a few extra growth rings.

PatM, could you also mimick adding growth rings by reinforcing the back rather than the belly? For example with a good coat of strong flax feathering out on both sides? That would be a lot easier, and could keep the limb working.
Just asking your opinion.

Offline Marc St Louis

  • Administrator
  • Member
  • Posts: 7,877
  • Keep it flexible
    • Marc's Bows and Arrows
Re: Chrysal or crack
« Reply #41 on: February 27, 2015, 12:35:08 pm »
You can use a long feathered out laminate in a working area safely.  You're just mimicking putting down a few extra growth rings.

PatM, could you also mimick adding growth rings by reinforcing the back rather than the belly? For example with a good coat of strong flax feathering out on both sides? That would be a lot easier, and could keep the limb working.
Just asking your opinion.

But then your "growth ring" would be violated at both ends
Home of heat-treating, Corbeil, On.  Canada

Marc@Ironwoodbowyer.com

Offline PatM

  • Member
  • Posts: 6,737
Re: Chrysal or crack
« Reply #42 on: February 27, 2015, 01:53:10 pm »
You can use a long feathered out laminate in a working area safely.  You're just mimicking putting down a few extra growth rings.

PatM, could you also mimick adding growth rings by reinforcing the back rather than the belly? For example with a good coat of strong flax feathering out on both sides? That would be a lot easier, and could keep the limb working.
Just asking your opinion.
  The crack is on the belly.

Offline joachimM

  • Member
  • Posts: 675
  • Good - better - broken
Re: Chrysal or crack
« Reply #43 on: February 27, 2015, 06:52:47 pm »
I got that it was on the belly. Rings are continuously violated on the belly so in itself that's not an issue. The point of mimicking a growth ring on the belly is to reinforce the bow and restore the balance between tension and compression. If the belly was weakened due to a crack, my reasoning is that you could make the intact belly wood interior of the crack take the compression load if you reinforce the back (you locally but gradually shift the neutral plane with a fiber backing). The net result should be the same as adding intact belly wood, but the procedure would be simpler.

As for violation of rings: it aint the violation per sé, but the angle of violation that matters according to Tim Baker. And glued flax threads aren't growth rings either. So its a bit weird to compare these.

You may or may not know: individual cellulose fibers are at most 25 mm long, even in wood. Wood fibers are merely bundles of stacked cellulose fibers held together by friction (and hydrogen bonds) in the lignin-hemicellulose matrix. So wood fibers, even on the back of a baby-bottom smooth growth ring, are continuously "violated" or terminated. The stacking holds it together. Just like with fiber backings, be they animal (sinew) or vegetal.

Offline PatM

  • Member
  • Posts: 6,737
Re: Chrysal or crack
« Reply #44 on: February 27, 2015, 07:46:12 pm »
You can't lay them down like mother nature though.