Is this a "chrysal"?

[FlintWalker]

This is on the belly of a hickory bow i've been experimenting with lately.  I roasted the belly over the stove. It picked up quiet a bit of speed and it's not showing the string follow it was but now it has these tiny little diagonal cracks.
  It won't hurt my feelings if it breaks but i'm just curious as to what these are and what caused them.  The bow had been shot before I toasted it and was a total dud. After toasting it, it shoots better than the first two I made. Scary how much better it shoots. I know it's gonna go south, just wouldn't be mine if it didn't.  What are these and how bad for a bow are they?   Thanks, Saw Filer   

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[Gordon]

Yes, those are chrysals, but they are not bad. The bow could last a long time. If you are worried, you could apply a path of rawhide on the belly side and wrap with serving or silk - that will prevent them from getting any worse.

[Pat B]

Yes, that is a fret, chrysal or compression fracture. What ever you want to call it.   Never try to remove a chrysal by scraping it off. You will have to reduce wood from either side of the fret to reduce the chance of more.   Pat

[a finnish native]

yes those are chrysals. I assume that the developed, because there might be a weak spot on the limb there. I could tell this from the wood grain showing in the pic. Right after the cryshals the grain or growthring gets wider, which means that there is more wood there.

[jkekoni]

Is that round belly? It looks like one.

Hickory it not a wood for round bellies. Most woods are not.

[George Tsoukalas]

Chryals are not good. They eventually lead to failure. The bow will fold on itself. I've had worse but I hate to see them on one of my bows. Over time, how long is a good question as it  depends, they will cause failure. There are  2 causes for chrysalling. One, a limb is bending too much in one spot because the tiller is off. Chrysals are localized. Fix it as Pat B described. Two, the design is not proper. The bow may be too narrow for the weight wanted, etc.The bow may not be long enough for a rounded belly.  Chrysals are not localized but spread out over a larger area. There is no fix for these except to understand their cause and design appropriately next time. Jawge

[FlintWalker]

The belly is flat.   
  The first few times I shot it, it took a lot of set. Somethink like 3" in the first 20 shots. It got so soft to draw I figured it was junk anyway and decided to play with it a little so I clamped it on a form and heated about 1.5" of reflex into it.
   I think what happened was that the wood cells that had collapsed during those first few shot were forced to stretch. Then when I added the reflex,  braced it, touched up the tiller, and eventually shot it, those wood cells that had suffered the most damage failed.
  I knew better than to try to force wood to bend one way after being trained to go another.
  Lesson learned.
On the brighter side, it shoots very good. Zero handshock, draws smooth and really spits a 540 grain arrow. It went from shooting 139 fps to 156fps at about 50# of draw. 
 It hasn't broke yet, but i'm gonna give it to a friend as a wall hanger before it does.
  If anybody here has a better idea as to what happened, i'd like to know. I'm here to learn.  SW
   

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[FlintWalker]

After looking very close, in every place it has these frets the limb is a few thousandths thinner than the wood around it.  I think that came after I heat treated the belly and it was not uniform in hardness.  I noticed when I would drag the scraper the whole length of the limb it would bite in some places a little harder than others.  I guess those are called hinges.  SW

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[George Tsoukalas]

A hinge is literally that. The limb actually looks like a hinge. Looks like you have some wash boards. Just some bumps from the scraper. Those may have caused the chrysals but not likely. Tough to tell without a full draw and/or a braced picture. Jawge

[Marc St Louis]

I've had that happen on bows that were shot in then heat treated and reflexed. I imagine that some of the wood cells have collapsed when the bow is being shot in and the heat treating tears the cells apart as the bow is being reflexed.

[Justin Snyder]

Thanks for posting Saw Filer.  I find this interesting.  I am happy to say I have never actually seen chrysals.  Justin

[Pat B]

When using a scraper on the belly I alternate the angles of the scraper as I go...straight one time then about 45deg angle to the right and also to the left and back to straight. This will help eliminate those washboards.   Pat

[NOMADIC PIRATE]

Or alternate scraper and file

[tom sawyer]

I think hickory is kind of prone to chrysalling myself.  I've had it happen a couple of times, and like others said it eventually led to the bow folding at those places.  Got quite a bit of shooting ouyt of them first though.  Its good that you've been able to see where the limb was just slightly thinner that those places.  USe this experience to see those humps and valleys in the future, and remove them before you even bother looking at the tiller.  You'll be amazed how well a bow will bend when you just smooth a limb by eyeballing it.  Its how an experienced person gets to a reasonable starting point for final tillering.  If its got a hump, no need to bend it and stress the wood there.  Just fix it first.

One other thing, I think hickory might be kind of prone to chrysalling, because people make the limbs so wide.  A wide limb needs to be real thin, and a thin limb has a very small thickness taper to make it bend properly.  A scrape or two in the wrong place and you have problems.  If your limb had been a 1/4" skinnier, you'd have had more thickness to work with and it would be less prone to tiller errors.  I used to make limbs wider, thinking it was safer.  In reality, its the opposite especially for someone who hasn't tillered a hundred bows.  I really like Badger's philosophy on tillering, he reduces width until he starts to see a bit of set during tilleirng, then he works on thickness.  This gets you to the right width for your particular piece wood.  It does require that you do the eyeball thing so your thickness is reasonably uniform though.

Just my two cents.