Primitive Archer

Main Discussion Area => Bows => Topic started by: Ifrit617 on October 12, 2013, 08:33:37 pm

Title: Rawhide patch for some small chrysals?
Post by: Ifrit617 on October 12, 2013, 08:33:37 pm
Hey all,

In Gordon's hazel build along he did a few years back he used a piece of thick rawhide to patch a chrysal. The most recent bow I've been working on has developed a few small chrysals about 17" from one tip and I was thinking of using a similar patch. How effective do you all think this method really is? Probably going to get some dog bone rawhide from the pet store and see how it goes.

Jon
Title: Re: Rawhide patch for some small chrysals?
Post by: PatM on October 12, 2013, 09:48:04 pm
I think  Gordon realized that a rawhide patch over a chrysal is entirely cosmetic. It has to be.
Title: Re: Rawhide patch for some small chrysals?
Post by: Ifrit617 on October 12, 2013, 10:43:03 pm
Just curious why that is?

Jon
Title: Re: Rawhide patch for some small chrysals?
Post by: George Tsoukalas on October 12, 2013, 11:37:48 pm
It works. Usually when a bow chrysals these days I don't shoot it much. To relieve the area, retiller above and below the chysals, since they are caused when the limb bends too much in that area. Then do the patch. retiller the other limb to match. Jawge
Title: Re: Rawhide patch for some small chrysals?
Post by: PatM on October 13, 2013, 01:52:19 am
Rawhide has no compression strength. The chrysal is still there. You're relieving the stress by re-tillering, not putting a thick piece of "tape" over it.
Title: Re: Rawhide patch for some small chrysals?
Post by: mikekeswick on October 13, 2013, 03:30:51 am
Rawhide has no compression strength. The chrysal is still there. You're relieving the stress by re-tillering, not putting a thick piece of "tape" over it.

+1
Title: Re: Rawhide patch for some small chrysals?
Post by: Gordon on October 13, 2013, 11:10:34 am
I don't use that technique anymore. If chrysals develop I now generally discard the bow.
Title: Re: Rawhide patch for some small chrysals?
Post by: BowSlayer on October 13, 2013, 11:33:34 am
If a chrysal is in the outer 1/3 of the limb then cut it there and make a short kids bow.
Title: Re: Rawhide patch for some small chrysals?
Post by: Badger on October 13, 2013, 12:29:07 pm
  I would normally discard the bow, I have noticed on some locust bows that I would have normaly trashed that the chrysals have remained shallow and don't seem to affect the bow but once I see them I just have no more confidence in the bow and it will really never be used to any extent.
Title: Re: Rawhide patch for some small chrysals?
Post by: Gordon on October 14, 2013, 12:41:07 am
Quote
I would normally discard the bow, I have noticed on some locust bows that I would have normaly trashed that the chrysals have remained shallow and don't seem to affect the bow but once I see them I just have no more confidence in the bow and it will really never be used to any extent.

It takes a certain amount of faith to hold a wood bow at full draw. Once I see chrysals, my faith in a bow evaporates.
Title: Re: Rawhide patch for some small chrysals?
Post by: mikekeswick on October 14, 2013, 07:31:47 am
Quote
I would normally discard the bow, I have noticed on some locust bows that I would have normaly trashed that the chrysals have remained shallow and don't seem to affect the bow but once I see them I just have no more confidence in the bow and it will really never be used to any extent.

It takes a certain amount of faith to hold a wood bow at full draw. Once I see chrysals, my faith in a bow evaporates.

Me too. There is a lot 'going on' at full draw  ;)
Title: Re: Rawhide patch for some small chrysals?
Post by: Pappy on October 14, 2013, 07:40:31 am
What Gordon/Badger/Mike /PatM said. +1  :)
   Pappy
Title: Re: Rawhide patch for some small chrysals?
Post by: adb on October 14, 2013, 10:13:14 am
A chrysal is a mistake. Period. It's either an error in tillering, design, or wood selection. It's a flaw caused by over stress that will eventually lead to failure. I've only had a couple bows chrysal (cherry and walnut) and they were both my fault. Both bows were abandoned to the scrap pile, and lesson learned.
Title: Re: Rawhide patch for some small chrysals?
Post by: PatM on October 14, 2013, 10:14:31 am
The only thing I disagree with is that a chrysalled bow is more likely to break. Wood is stronger in tension so a collapsed belly puts less stress on the back. A hinged chrysal perhaps but not a chrysal with no apparent disruption to the drawn profile.
Title: Re: Rawhide patch for some small chrysals?
Post by: George Tsoukalas on October 14, 2013, 10:49:23 am
Well, the long time bow makers have to remember that they have many bows in reserve.
Newcomers do not.

A chrysalled bow can be fixed and can last for awhile. It will not last "forever". It will eventually fold on itself like closing a book. . Don't ask me how I know that. LOL.

There are 2 causes for chrysalls.

First, if the design is stressed (too short, too narrow, too much weight) the bow could develop them. In this case they will be spread out over one or both limnbs and likely all along the limbs.

Second, the chyrsalls are localized and form in certain areas because the limb bends too much there. The fault is bad tillering. To fix, leave the chrysalled are a alone and retiller above and below to fix the tiller. Retiller the other limb to match. For insurance add a rawhide patch to buttress the area.

Jawge
Title: Re: Rawhide patch for some small chrysals?
Post by: PatM on October 14, 2013, 11:14:11 am
Still not sure how you think something with little bend resistance is buttressing anything. The thickest rawhide patch available can still be bent and creased with bare hands.
Title: Re: Rawhide patch for some small chrysals?
Post by: Badger on October 14, 2013, 01:38:24 pm


The only thing I disagree with is that a chrysalled bow is more likely to break. Wood is stronger in tension so a collapsed belly puts less stress on the back. A hinged chrysal perhaps but not a chrysal with no apparent disruption to the drawn profile.


  Pat, proably most of the bow failures actually happen at the belly before the back breaks. Once a bow has chrsaled it is weak there and can hinge and cause an instant failure at any time.
Title: Re: Rawhide patch for some small chrysals?
Post by: Gordon on October 14, 2013, 02:16:59 pm
Quote
Once a bow has chrsaled it is weak there and can hinge and cause an instant failure at any time.

+1
Title: Re: Rawhide patch for some small chrysals?
Post by: George Tsoukalas on October 14, 2013, 06:29:58 pm
That's the reason for the patch. It's temporary. The bow will fold up there. Jawge
Title: Re: Rawhide patch for some small chrysals?
Post by: wood_bandit99 on October 14, 2013, 08:10:22 pm
I have heard people taking needles and putting holes above and below it then put sinew on the back for a patch