Weird thing during drying

[FilipT]

Its been almost a month since I started to dry my two hazel bows. Both were roughed out green trees and clamped to a aluminum bar and put into shed for drying.
But this shed is used for firewood and tomorrow new batch of firewood will be put into. So I had to put bows elsewhere. I put them yesterday in most similar place, my attic and basically only place with good air flow. Although temperatures seem to be higher there because of asbestos plates (roof).

Here is what happened on bows when I checked on them 10 minutes ago. Belly looks convex in shape instead of flat. So bow wood look like shallow "D" in cross section.
What do you think happened and are my bows destroyed?
I really don't want to throw all away just because of some nuisance which was unavoidable.

[wizardgoat]

Sound to me like maybe they lost a lot of moisture when you put them in your attic.

[DC]

Are they still strapped to the bar? When you say "cross section" that's like cutting the bow and looking at the end of the cut?

[wizardgoat]

If your belly was flat when you roughed it out green, the wood on the sides is much thinner than the centre and probably dried out and shrunk quicker than your centre

[DC]

That's what I was leading up to in my round about way. Wood shrinks a lot across the grain and very little with the grain. I think the sapwood has more water in it so it shrinks more. As long as it's not checking you're golden.

[FilipT]

Yes, they are still clamped. No checking at all. Yes by cross section I mean if you would in your mind cut the bow in mid limb you will see that it has that pronounced rounded belly instead of flat like it was when roughed out green.

How long do you think I should leave it like that, clamped to the bar? I plan on leaving it one more week then unclamp and put it in my room with everyday doing weight checking. When it stops loosing weight it will be ready for tiller.

[DC]

It still might want to take a lot of reflex if you unclamp it. If you do, keep your eye on the reflex and if it starts to take too much(more than a couple of inches) clamp it back down. I don't have a lot of experience with Hazel. The two staves I have warped pretty badly but they were from the same tree and they may not all do that.

[FilipT]

Will that convex belly shape go away during drying or will it come off only during tillering?

[DC]

In my experience it will only go away when you cut it off. I'm wondering if it mostly happens only on small diameter staves(saplings and branches) I've really noticed it on Ocean Spray which are typically 2" or less in diameter.

[PatM]

The final belly shape is up to you. It's not going to defy your efforts now just because it dried and altered shape.

[Hamish]

Attics get too hot for drying green staves. Even seasoned staves can dry out too much.

[penderbender]

I noticed that a lot with oceanspray as well. It won't matter, you'll just have to make it flat again. Cheers- Brendan

[FilipT]

Ok, no problem in getting it flat again. I was just wondering if that bulb will come off during drying as like you say its thicker because it dries slower then sides.

[stuckinthemud]

That kind of shape movement is called cupping sometimes, its fine, its where the drying stress has gone instead of checking; hazel is really forgiving and makes an excellent bow.  I would rough out the shape of the bow and then let it finish drying. Del just finished a hazel bow and really pushed the drying speed out to the max with no problems - he cut the stave in early June and finished the bow at the start of August and that's just 8 weeks from start to finish.

[FilipT]

I plan on unclamping bows in Friday, next week and then take them inside the house and watch if they will develop reflex or not and of course weigh them every day.