Troublesome Yew Stave

[babbott]

I have a Yew bowstave, 74" NTN, with nice grain and sapwood, but as it has dried, it has become quite curved.  It has a pronounced deflex at about two-thirds of its length, and it also bends to the side at a similar point.  I was thinking that I could rough out the shape, then steam it to straighten it.  Has anyone tried this type of treatment?  I have seen a guy on TV make a recurve with yew, so I know it can be done.  Does anyone have any advice or warnings?  Here are two pics of the stave:





Thanks for any help,
-Ben

[Marc St Louis]

Ben
Yew bends well with dry heat. You could rough out the bow then use dry heat to starighten it out.

[SimonUK]

Sorry for jumping in on the thread Ben, but I have a related question.

Marc (and others), I need to correct some string follow in a yew bow. It has 2.5 inches of string follow and has only been tillered to about 27 inches.

Can I apply dry heat to the bare wood? Or should I complete the tillering, apply my finish of linseed oil and bees wax, then heat it?

Thanks

Simon

[SimonUK]

Ben, in my limited experience with narrow bows like elbs, I find it very difficult to line up the tips when straightening a roughed out bow.  So I try to keep the stave as wide as possible when straightening. Then you have some wood to play with when marking your centre line.

With that sideways bend I imagine you'll need to narrow it a bit though.

[Marc St Louis]

Sorry for jumping in on the thread Ben, but I have a related question.

Marc (and others), I need to correct some string follow in a yew bow. It has 2.5 inches of string follow and has only been tillered to about 27 inches.

Can I apply dry heat to the bare wood? Or should I complete the tillering, apply my finish of linseed oil and bees wax, then heat it?

Thanks

Simon

Simon
I used dry heat to take some deflex out of a Yew bow I was tillering and it worked well. I just applied the heat directly to the wood. If you use a heat gun then use the high setting and keep the gun about 4" away from the wood. Keep heating till the wood starts to darken in colour. If removing set or deflex then you would need to reflex the limb as you were heating it.

[SimonUK]

Thanks Marc, that's very helpful.  I presume I'd need to let the yew re-hydrate for a couple of weeks before bending it again?

[boze]

 Simon ya could always steam it.

[adb]

Use dry heat, not steam, for removing deflex. Steam will add moisture, and will just renew the deflex. Steam works for moist wood, or for flipping tips.

[Yeomanbowman]

If you do choose to use steam it will loosen the bark as a helpful side effect.  Whilst it's hot it will be really easy to remove it and there's your bows back ready made.
Also steamed wood should be held in the reflex position whilst it dries for about 2 weeks, according to my wood working books.

[Marc St Louis]

Shouldn't take that long Simon. I usually wait at least a couple days but less than a week before I resume tillering

[babbott]

If I do use dry heat, do I brown the sapwood as well as the heartwood?  Is the intention to heat the stave all the way through, or just the surface?  Is it an iterative process, or do I get just one shot at it?  Should I hyper-flex the stave while cooling in anticipation of it springing back, or just clamp it flat?  Is steam safer for the wood if I clamp it for two weeks, as indicated? 
Thanks,
-Ben

[Yeomanbowman]

Shouldn't take that long Simon. I usually wait at least a couple days but less than a week before I resume tillering

Marc,
Simon lives in Scotland, which is not exactly known for it's arid conditions.  OK 2 weeks may be 'belt and braces' but that's me when making bows.  What adjustment would you make for a cold and damp climate?

[Marc St Louis]

I would say it a humid environment you would be safe to tiller after a couple days.

[SimonUK]

That makes sense. I'm planning to use dry heat, so the damp in Scotland should accelerate the re-hydration.

[a finnish native]

teh mistake you made was that took the bark and some wood off the belly side and left the bark on the back. at least rowan twists some deflex into it if done so.
you can stam that out or use dry heat.