hickory backing failure!

[vespid]

I made a beautiful ipe pyramid bow with a 1/8 inch hickory backing. I got about 300 shots out of it when the hickory backing started to crack. its sitting on my display now never to be shot again. The backing cracked crosswise in three places along the bottom limb. there's a crack pretty much in the center, one about 1/4 up from there and one about 5 inches from the handle. its like the whole thing was stretched out and it was failing everywhere. the cracks don't appear to be aligned with any grain problems. they're just spread out along the limb

 I am really disappointed and confused. I thought hickory was the ultimate backing material. The ipe doesn't show any signs of wear on the sides or belly. the tiller was good. I cut the backing strip from a hickory board using my table saw, and glued it onto the ipe board before cutting the bow out. the backing edges were rounded to 1/4 inch and the whole thing was sanded to 320 and steel wooled...finished with shellac.

 is there a secret to this? is there some right moisture content for the hickory or some special glue to use? (I used titebond 3).

any thoughts? I have another pipe board. should I back it with something else? thanks for your thoughts!

[Roy from Pa]

An ole timer told me that before I put a hickory backing on a bow to give it the U bend test. He said bend it into a U a few times. If it's going to break it will break then. You could sand the backing off and put another backing on it. You just have to be careful sanding and stop when you start seeing the glue line, then finish sanding by hand.

[Trapper Rob]

Roy you say a ole timer told you that must have been a long time ago because I thought you was a ole timer  

[Roy from Pa]

Another ole timer told this ole timer:)

[Pat B]

What glue did you use for this hickory backing? If you used TB glue you can heat up the backing and when the glue reaches 150deg it will release. I have done this on a few backed bows with good success. I called the TB folks when I had a similar problem and that is what they suggested.
  I have made many hickory backed bows and only had one backing failure. I have used hickory backing strips that had terrible grain violations and none of them broke. The only hickory backing that ever broke was one that wasn't handled properly after the tree was cut and fungi moved in. That is when I called the TB folks for info.
  I start heating one tip and when it gets hot enough I wedged a flat screw driver between the backing and bow and heat and work down that limb to the handle. Then start at the other tip and work towards the handle.
 Once you remove the backing clean up the stave and add another backing strip.

[vespid]

thank you for your suggestions! it was titebond 3 so i think i'll try heating it to remove the backing. if that doesnt work ill start sanding...

before gluing i bent the backing well beyond what i would expect a bow to bend. Maybe i bent it too much?  

if i can save it ill post pics.

thanks again!

[mwirwicki]

I had a batch of backings that were dry rotted.  The breaks were straight across.  The bows broke before they were finished.  I've never messed with Ipe but try thinning your backing to 3/32.  Sometimes 1/8 is too thick for some of the harder, tropical species.

[red hill]

Vespid, PatB is right. I followed his advice and removed a couple of hickory backings and saved both bows. The biggest problem was cleaning up the old glue and that wasn't so bad.