Small crack

[arkdoc]

Hey guys, I have lurked if you will for a while, but I just officially joined and have a question.  I am building an osage bow.  I have been tillering the bow and when I strung and first drew the bow back heard some ticking.  After examining the bow I saw a small horizontal crack in the back that looks about 1-2mm close to a knot.  The crack is only visible when the bow is strung/drawn.  The crack cannot be seen when unbraced.  I was planning on stringing the bow and applying glue to the crack and then unbracing and let dry and then applying a sinew wrap to patch.  It is hard to get a picture due to not being visible unbraced, but I might if I need to.  Just looking for advice to see if this will work.  Thanks!

[Pat B]

Pics would be a real help.   Brace the bow, fill the cracks and over the knot with super glue, unbraced and let the glue cure. Also, while braced but before adding the glue, rub a cotton ball all along the bow's surfaces in both directions. If there is another crack it should snag the cotton.

[arkdoc]

Thanks, I will try to get some pics of the bow. 

[Pat B]

Did you leave the back ring un-violated at the knot or take the top off the knot while chasing the back ring?

[arkdoc]

I was pretty sure I left it unviolated, but I might have slipped up.  I did the cotton ball test and there is a vertical splinter at the same spot.  I took some photos, but I'm not sure how great they are, but I took them.  Couple of questions.  Do I need to use photobucket to post pics?  Also, with the bow, does it need to be superglue or can TBIII work?  I have TBIII at the house, but not regular super glue.  Thanks

[Pat B]

Super glue works best because it is so thin that it sink way down into the crack better. I guess you could force the TBIII in with a finger then close up the crack but I haven't tried that. After the glue has cured I'd either sinew wrap that area or add a rawhide backing.
  If your pics are sized at 640x480 you can use the "Attachment" option below but Photobucket or other photo hosting site are easier because you can reduce the pics to an acceptable size then just copy and paste to PA or other sites.

[arkdoc]

I am attaching a pic to see if it will work.

[arkdoc]

Well it didn't pop up, but if you look at it, I outlined the splinter and the crack is on the right side of the knot and no wider than the knot.  You can see my thumb for comparison and I don't have the biggest hands. 

[Pat B]

That looks like a splinter lifting. I thought you were talking about a check coming from the knot. This is where pics really help.
Super glue and a sinew wrap should alleviate that but I'd use super glue so I was sore it would get way down in the splinter. Super glue in an ventricle art of my bow building kit. I usually buy the stuff in a bottle rather than a tube but I think any will work.
How far are you into the tillering process? A sinew wrap can make it difficult to tiller.

[arkdoc]

Yeah, I saw the splinter today, there is also a tiny crack that is hard to see.  I will get some super glue to take care of it.  I am almost done with the tiller I believe.  I think the bow might be a little light on draw weight though.  I will patch this and then see how it goes.  I am considering flipping the tips if I can and trying to decide if backing with sinew might be a good idea...

[Weylin]

My advice is to not flip the tips or sinew back your bow. Flipping the tips puts more stress on the limbs and since your limb already cracked it's telling you it cant take any more. While sinew-backing might potentially help this bow I don't think it's worth the risk. What I mean by that is, sinew is valuable, the process is time consuming and requires a loooong wait period. Most experienced bowyers who sinew back bows plan to do so from the beginning (and designed accordingly) and only do it to bows that are in good condition. I think it's just not worth going through all of that with a bow that very likely could give up the ghost anyway. I'm not trying to sound like a wet blanket. I really hope you pull off your patch and get a sweet shooting bow but if you do, I'd leave well enough alone and pat your self on the back. Good luck and follow PatB's advice. 

[arkdoc]

Thanks guys, I appreciate the advice.  I hope it works and if it doesn't, then I guess that just gives me an excuse to make another one now. 

[Pat B]

Weylin gives good advise about not flipping the tips and not sinew backing. Get this bow tillered. At this point don't worry bout the weight, concentrate on getting it tillered out well. If it comes out too light there are plenty of
un-bowed kids out there that would like to have it. Good tillering is the most important aspect of wood bow building. Without good tiller all you have is a bent stick.
 I hope you don't need a good excuse to make another. That should be a given! 

[bushboy]

Is it possible to take it down to the next ring?a heavy heat treating will add about 10lbs.another option is to sand it flat and add a bamboo backing or another type of hardwood.a bamboo backing will roughly triple the draw weight from what I've seen.

[George Tsoukalas]

Knots have to be carefully worked. Leave the area wide. When tillering, leave that area slightly flat as it should noe bend as much the rest of the limb.
Put some superglue in the crack and wrap it with thread set in epoxy.
Jawge