Experienced bowyers: how worried should I be?

[nineworlds9]

So I acquired a bow second hand built by a well known and reputable bowyer, I believe it's a handful of years old.  Bow was in seemingly excellent condition  when received, but I missed something that I didn't notice until I got out in the bright daylight shooting, just happened to have light at right angle and caught it.  

Bow is a radical static tip design, bamboo with clear glass.  I can't hear any noise while stringing and unstringing, or while shooting.  I am using 10gpp with proper nock fit/ again I think this was something I just missed on unpacking, it's not something that occurred under my watch, I've only shot the bow maybe a dozen times.  

I have contacted the bowyer very respectfully just asking for opinion, just want to know if I need to be wearing safety glasses shooting this one or if it's good to go.  Depending on what happens I may just dump the bow on the market for half of what I paid with full disclosure.  It might sell as its a very desirable bow and specs with a long wait.

   
   

I just don't know if these are harmless stress or what.  They are just outside the fades where the limb starts to deflex.

[SportHunter]

Looks like the wood has some stress fractures under the glass, I had a bow with a similar issue and seeped in some Loctite 420 just in case and haven't had any problems.

This was on a longbow on the lower limb so not much to worry about, in your case it is at the fades which indicates too much stress is happening at the fades and eventual failure is probably more likely, just my 2c.

[Mad Max]

Can we get a side view of the whole bow?

Is that the back or the belly?

[nineworlds9]

Originally posted by Mark Daniel:
Can we get a side view of the whole bow?

Is that the back or the belly?

The pictures are showing the the back (front) of the bow, top limb, just above the fade where limb goes from reflex back to deflex.  

I would do a whole profile, but I'm pretty sure that would identify the maker, and I don't want to cast any doubts on his work more or less/ good etiquette??

[mikkekeswick]

Without seeing the whole bow it is difficult to say what caused it. If we don't know what caused it we can't give specific advice to your problem other than give general 'fixes'.
If one of my designs had failures I'd want to know about it!

[Bowjunkie]

The fact that it's happening right at the riser fadeout makes me wonder about the degree of taper in the limbs, whether it's been drawn too far for its design, and whether all glue joints are sound. I see it has a power lam and it's still failing right there above it. I never was sold on those things. One of the glue joints I see in the picture looks possibly suspect. I'd closely inspect the glue joints in the area too... at brace and during the draw.

Any word from the bowyer yet?

[nineworlds9]

If you mean the head on shape of the limbs then they are pretty well the same diameter from fade to about the last 1/4, after which they taper pretty radically to very small static tips.  One of the longitudinal lines in the pic is just a play of the light.  There is no power lam as far as I know, I think you're seeing the tip of the riser fade in the pic.  The bow is 3 lams of bamboo and clear glass back and belly.  The core bamboo lam is the thickest and the outer lams are thinner.  The tiny cracks are on the edge of the back lam.  The bow is rated to be safely drawn to 31" and is a 58" bow.

I got the following info from the bowyer this morning, along with a few other questions:

"Chuck
Keep watching it and let me know if it gets worse, however do not be afraid to shoot it. I don't think it is going to blow up on you."

[Bowjunkie]

Ok, so the line I'm seeing that looked like an extra lam/glue line must just be some natural streaks in the thicker core lam.

31" draw can be done with a 58" bow, but I'd have the whole limb working evenly and use a short riser to maximize working limb length. How/where the limb works is a result of the total degree of taper... width and thickness combined. Static tips require more work to be done by the remaining limb length.... and the bow is already short for the draw length so...

How long is the riser?

The fact that it's failing at the fadeout points to too much stress there for some reason(s).

[J. Holden]

I have no idea how to answer your question as I'm not educated enough in the ways of bowmaking.

But, I do want to publicly commend you for how you're handling the privacy of the bowyer.  We've all seen too many times where a bowyer is bashed because of some mistake.

I'd gladly share a camp with you any day.  You sir have great ethics and morals!

     

-Jeremy  

[nineworlds9]

Thanks Jake.  I greatly respect the bowyer in question, he is a real artist and archery advocate.  I sent someone else who replied to me here pics privately of the bow.  

I've spoken with the bowyer again and he is confident that I should just shoot the bow without fear and just keep and eye on the marks...I measured them in millimeters and I plan on checking it periodically to see if it grows at all.  Bowyer does not think it will as the majority limb bending actually occurs higher up the limb.  Also the bow is a handful of years old, so has some mileage on it I believe.  

Thanks for your words and I would enjoy sharing the fireside with you any time.

[mikkekeswick]

31 draw on a 58 inch bow....no wonder it is stressed out of the fades.
It doesn't matter where 'most of the bending' occurs the fades are always the most stressed spot on a bow. Stress then lowers as you move progressively along the limb to the tip.
I would suggest that it has been overdrawn at some time.
A core lam getting a minor crack like that isn't really anything more than a cosmetic issue. The glass is doing all the 'work' and the core is just resisting sheer. There is however a limit to what a core can take and if that boo had less than perfect gluelines (not the bowyers gluelines - the gluelines in the actioboo) at that spot it could cause issues like this.

[nineworlds9]

it is a very radical design from what one normally encounters in tradbows.  the 60" version of same model maxes at 33" LOL.  Thanks for the insights, I think this is exactly what the bowyer was implying.  The comment about the bending was my interpretation of what was explained to me, just to be clear.  I am going to keep the bow.