Self bow crack questions...please help!

[dinorocks]

I'm working on a few self bows for my family and noticed some cracks in the back of two and on the side of the other...see picts below.  Should I worry about these?  Any suggestions shy of backing them?

There are several cracks on the back, parallel to the grain, on two of the bows...I believe that the cracks on the bow pictured below (15# for my son) were caused when the bow was heated to remove propeller twist.  I started this bow from a stave.  The other bow (35# for my wife...not pictured) also has the same type of cracks...I bought this bow as a blank and didn't notice the cracks until a few days after I completed the tillering.  I slowly removed lots of wood and wall-tillered everytime I made a few passes with my scraper to get it to 35#.

On my bow pictured below (50#), I observed a crack on the side near the top tip when I bought it as a blank...this crack was glued before I started floor tillering but appears to be open again after I finished tillering.  I plan to add more glue.  There is also a parallel crack on the back near the side crack but it is not connected.

I have completed most of the sanding/steel wool work but have not used my Formby’s Tung oil yet...waiting until I resolve the crack issues.

I'm an amateur bowyer and any suggestions would be greatly appreciated!!    

Thanks!
Dino

 

 

[ringo64]

i would not be all that worried about the cracks parallel to the grain on the back, but the one by the tip is trouble.  i wouldn't even want to draw that bow..... it is just waiting to explode.  can u shorten it?  maybe shorten it and back it. i wouldn't even back it as it is..... wouldn't want to put all that effort into something that was beginning its life flawed.  i think that the parallel cracks are just drying cracks and they should be alright as long as they don't run off the grain.  just my opinion. good luck.

[Frank]

I've made a few bows with cracks along the belly over a foot long.  I usually wrap sinew around the limb just for caution.

The crack on the side, I'd sinew it on a light bow, but 50lbs is iffy.

You did not mention what kind of wood the bows are made of.

If osage, I'd sinew and wrap that side up and give it a shot.  Any other wood, I'd pass.

This is just my buck two fifty.

Good Luck,

Frank

[dinorocks]

Sorry...the bows are made of Osage Orange.

Thanks,
Dino

[Jacko]

I would attempt a repair on the bow with the crack near the limb tip . It is not under the same strain as nearer to mid limb .

Try bracing the bow and carefully partially drawing the bow just enough to open the crack very very slightly and dribble some cyanoacrylate glue [ super glue] into the crack , wipe any runs and clamp it for a while , clean off an excess and drill a hole small enough for a small brass nail to be hammered in with light blows - drill only slightly deeper than the crack , a bit of glue could help at this stage ,file off the brass pin flush , bind the limb in rawhide or sinew well soaked in hideglue or better yet a waterproof pva glue as suggested earlier . My bet is after this repair it will shoot on with no illeffects .

If bracing the bow worries you try opening the crack by hand bending and follow the above steps , Do not lever it

By way of decoration you could bind the other tip to match , try tying a turks head knot of rawhide strips each end - looks great

regards Jacko

[Eric Krewson]

Yikes! Don't drive a nail in your bow limb for any reason.

Fill the back cracks on bow #1 with super glue and forget them. I have had these same kind of cracks appear while straightening a limb, never were a problem after I glued them.

I fixed a similar crack on a tip during the ASTB tournament at Tannehill a few weeks ago. I soaked the crack with superglue, wrapped the crack tightly with braided serving material and soaked the wrap with superglue. This is a solid patch and will prevent any future failures.

Here is a similar patch I did on another friends bow this week.

 

A complete sinew wrap is just about bullet proof, a little ugly but very stable. I did this one on a bow that was broken in half except for the bamboo. I glued the pieces back together with urac and wrapped the break with sinew soaked in Elmers exterior wood glue.

 

I have done several cracked tip repairs with sinew and wood glue over the years, all are still shooting.

[d. ward]

As Eric mentioned I would skip the nail as that will cause a stress point.I would fill them all with the thinest super glue you can find...Not gel type but some really thin as it will penatrate the crack.Then rap it with thread and more super glue over the thread.I've repaired more then 100 self bows over the years and I would say about 80-90% are still shooting.One thought is the light draw weight your bows have...If they were 50 plus pounds draw weight they may not hold...but light draw wts.generaly are OK.Another thought would be to back the bow with some type of snake skins or cloth ???...bowdoc