Hairline cracks in belly?

Buxndiverdux · October 11, 2012, 05:49:00 PM

Sitting here in the stand with a glorious sunset admiring my newest self bow and Ive noticed some slight hairline cracks in the belly. It appears as though they are in the spar urethane finish only and in a working part of the limb. What can I do to fix it? And is this cause for alarm? Thanks

Pat B · October 11, 2012, 07:26:00 PM

Do they run across or diagionally on the belly? If so they are probably frets(chrysals, compression fractures). Frets are caused when an area bends more than the surrounding area creating these stress fractures. Sometimes they aren't a problem but most of the time they mean trouble for your bow.
Pics will help ID them.

Buxndiverdux · October 12, 2012, 04:38:00 AM

They dont really have a set pattern. Some are left to right some are diagonal. None are more than 1/4" long. Most are 1/8".

PEARL DRUMS · October 12, 2012, 10:19:00 AM

Those are compression fracture, frets or chrysalls, whatever you chose to name them. Your belly wood is working overtime in those areas. You cant get rid of them and the bow will slowly collapse. Sometimes quickly, sometimes slowly, but it will happen eventually.

Buxndiverdux · October 12, 2012, 12:54:00 PM

Can I remove some material to lower the poundage to reduce stress? What can you do to prevent in next build?

PEARL DRUMS · October 12, 2012, 01:07:00 PM

Hinges, or weaker spots cause frets. The wood collapses under the compression because wood before and after that spot is stiffer. You can remove wood before and after the weak spot to balance it out. Odds are those frets go deeper than you may think and will require alot of removal. I would suggest letting it go and start another bow.

Buxndiverdux · October 12, 2012, 02:50:00 PM

Any suggestions how to keep this from happening again? I used a tillering gizmo and it looked good to me. I've probably shot it 100 times already. I forgot to say its a bamboo backed hickory stick.

PEARL DRUMS · October 12, 2012, 02:55:00 PM

Thats a good combo when used properly. How wide did you leave it? Post a full draw and front view pic if you can.

Buxndiverdux · October 12, 2012, 03:02:00 PM

I don't have a full draw picture handy, but its 69" NTN and about 1 5/8" wide at the fades and tapers down to around 3/4" at the tips. It scales 50# @ 26". It shoots real nice. I hate to loose it. I will try to get some pics up tonight or tomorrow. Thanks for all the help.

PEARL DRUMS · October 12, 2012, 03:16:00 PM

Wow. Thats very long for that combo and that draw. Those limbs are barely working. Im suprised in chrysalled at all. It almost has to be one of two things. Your tiller isnt as good as you think, or the hickory isnt dry enough.

Buxndiverdux · October 12, 2012, 03:29:00 PM

Well... I guess it could be both? I don't have a moisture meter. My tiller looked good to me. I've read many treads with pics on tillering and have seen hinges and how to correct them. I've watched youtube videos galore, read TBB volumes 1-4. It sure would be nice to have an experienced boyer close by to pester for info. I pick stuff up pretty quick. This is my 5th self bow project.

rainman · October 12, 2012, 03:50:00 PM

Sand the finish off and make sure it is only there first if you can't get a close up picture. With those dimension and you used a gizmo I would suspect the finish before the wood. Need some pictures.

rainman · October 12, 2012, 03:52:00 PM

You can sand down the wood till they are gone and glue another piece of wood to the belly and retiller to save it.

Buxndiverdux · October 12, 2012, 04:18:00 PM

Would it crack the finish if I bent it before it fully cured? I will admit that I didn't wait 24 hours after finishing it.

Roy from Pa · October 12, 2012, 05:27:00 PM

Yes it will:) Tongue oil is a good, simple finish.

George Tsoukalas · October 12, 2012, 05:58:00 PM

Are the chrysals spread out over the entire limb or are they localized to spots here and there? If they are localized to spots then those areas are bending too much in relation to the rest of the limbs. That is most likely what is happening to your bow considering its length. If they are spread out then that's a design problem. Jawge

Buxndiverdux · October 12, 2012, 09:28:00 PM

Localized to spots here and there. There are a few on top and bottom limb.

Buxndiverdux · October 16, 2012, 08:24:00 AM

I sanded on it a little last night to see if it was in the finish only or the wood. They are in the wood. Any tips on how to stop it? Or should I just start another bow?

Can I save the bamboo backing? Is there something out there that will make the TB3 let go but not bother the Bamboo?