Q about OO - MicroCracks ---FINISHED BOW page3---

[PaSteve]

I have less experience than most here. I experienced the same type of micro cracks after taking twist out of an osage bow. I thought I had damaged the bow and it was going to break. After consulting with Pearl he told me to allow the bow to dry out, fill with thin super glue, finish tillering and enjoy my new bow. That's exactly what I did and there have been no issues.

[bradsmith2010]

One thing is rawhide won't hurt anything,,.it can be applied during or after tiller,,.it does protect back from harsh hunting conditions,,your bow could last 100 years with out it,.if u put it on and the bow never breaks,,,you don't know if its helping or not,,.pope and young stated a significant reduction in bow failure after using rawhide on there bows,,.of the bows I made for others,..I can't think of any that failed,..with rawhide
    This bow may not need it,,,just keep the rawhide in mind for future projects

[backtowood B2W]

Thank you guys!
I will try to get it done without backing. As it is my first OO I am somehow curios about its abilitys.
BUT I will also look for good rawhide. Always good to have some around. I like silk and linen backings as well but raw hide just looks more primitive.
Any good sources for rawhide in Europe ? Goat or calv would be great right?
BTW

[PEARL DRUMS]

Those are drying checks caused by the heat.
Let the stave dry some more before making a bow out of it.

Bingo. The stave was too damp and the heat expanded the internal moisture causing it to make cracks and escape. Structurally, you are just fine. But let it sit in 50% RH, or lower, for at least a few weeks.

[bjrogg]

Those are drying checks caused by the heat.
Let the stave dry some more before making a bow out of it.

Bingo. The stave was too damp and the heat expanded the internal moisture causing it to make cracks and escape. Structurally, you are just fine. But let it sit in 50% RH, or lower, for at least a few weeks.

I often give another coat of shellac on the back before steaming.
Bjrogg

[Eric Krewson]

Experience talking here, for me it is the severity of the bend you are straightening rather than the moisture content that causes these micro cracks. All of my wood has been seasoned up to 20 years with none less than ten. If I take the really sevier propeller or a 45 degree dogleg out I will encounter these cracks sometimes but not always, some osage is more flexible than others.

I do think you can get the surface too hot too quickly and get these cracks as well.

[Hamish]

The cracks don't look like they run off the edges, so you can get away without a backing.
 
One thing to remember if you superglue then heat treat/bend it again, the superglue will evaporate.

I sometimes used to get small pressure cracks like that when I bent osage with dry heat. Using spray on cooking oil seemed to solve the problem.
It can happen even with well seasoned wood.

[backtowood B2W]

Experience talking here, for me it is the severity of the bend you are straightening rather than the moisture content that causes these micro cracks. All of my wood has been seasoned up to 20 years with none less than ten. If I take the really sevier propeller or a 45 degree dogleg out I will encounter these cracks sometimes but not always, some osage is more flexible than others.

I do think you can get the surface too hot too quickly and get these cracks as well.

This stave has been seasoned longer then 10 years for sure.
I steamed both limbs and the handle and the cracks only appeared where I had the worst propeller twist.
The cracks appeared over night not by steaming it, ok maybe they were there already showing up when the damped surface dried up.
I will definitely protect the back of the other twisted staves I have. Thanks bjrogg for the tip.
Would soaking the bow in water overnight help to avoid this cracks too?

[bradsmith2010]

I have heard others mention,..different steaming times...effected the checking...

[Eric Krewson]

I witnessed similar checks one time that really surprised me. I had a stave leaning against the wall in my garage next to my work bench, we had an abnormally dry day on summer with the humidity at almost nothing.  I looked at my stave and the back was riddled by hairline cracks, dozens of them. I thought "this stave is toast" and put it aside.

A few days later, after the Alabama humidity returned to normal I looked at the stave again and there wasn't a check in the back anywhere. I made a bow from the stave, when I put the finish on I know all the checks would show, none showed, they had opened and closed like they never existed in the first place.   

[DC]

I've had them open and close like that when I'm heat treating. They open when it's hot and close up when it cools off.

[rps3]

Put me in the thin superglue and make a bow category. Never had a problem with checks like that.

[PEARL DRUMS]

It makes no difference how long a stave has been cut. It only matters how dry it is and that changes with the RH. A 20 year old stave can be too wet to work if it was stored in 70% humidity for a few months.

[Weylin]

It makes no difference how long a stave has been cut. It only matters how dry it is and that changes with the RH. A 20 year old stave can be too wet to work if it was stored in 70% humidity for a few months.

especially with a freshly chased ring. I like to shellac a chased ring regardless of how seasoned the stave is.

[SLIMBOB]

Ive had an Osage belly split check badly the moment I exposed the back ring.  The stave was 5 or 6 years old and the back split had not one check on it.  It had sat as a belly split for a year before I chased a ring.  It checked literally before I could shellac it.