questions about using heat to straighten a hazel stave

[stuckinthemud]

Hi All

I am absolutely certain that this question has been asked and answered many times but finding the relevant threads is proving elusive, so apologies in advance, but...
I have rough-tillered a hazel stave and find that the long limb needs to be corrected a tiny amount - the tip needs to move from right to left about 1/2 an inch.  The hazel is probably still slightly green - I cut it about a month ago and kept it in the house while I worked it, limb thickness is about 11mm; the profile is hollow-limbed pyramid and it has spent several days on a cool radiator.
So then, is it OK to use a heat-gun to tweak the limb, or should I use steam, and how long will the affected area need to 'rest' after tweaking as I am not intending to heat treat the bow.

Stuck

[Gordon]

If the wood is still green I would use steam heat for the correction. Then I would let the wood dry completely before doing any serious tiller work.

[wizardgoat]

And strap it to a board very well or you will have a lot more than 1/2" to deal with by the time it's dry

[JackCrafty]

Minor corrections can be done with dry heat on any type of wood.  It really doesn't matter how dry the wood is with slight corrections like 1/2".  That's what I do.  I use a heat gun to make minor corrections during all stages of bow building.  Some wood responds very well and some wood will remember it's shape and drive you nuts.  You won't know until you get into the process.

Hazel will probably bend back to it's original shape, or close to it, unless you "overbend" it and then clamp it to a board with a wedge under the bend.  When you take the bow off the board, the wood will snap back a little so make sure you have a slight "overbend".  Overnight indoors clamped to a board is usually enough time for the bend to take if you use dry heat.  If you use steam or if the wood is green, it may take up to a month for the wood to dry out enough to continue working.  You will probably need to keep making slight corrections all the way through the process of tillering.

Major corrections  (2" or more)  or bending  (like making a gull-wing bow)  are usually done with steam while the wood is green but can also be done with certain woods after they are dry  (like red oak).

[steve b.]

I wouldn't hesitate.  But depending on how wet it "feels" I might heat it up slowly and watch for checks on the belly.

[vinemaplebows]

Just but a cheap microwave...bending in 3 munutes.

[Billinthedesert]

Vinemaple: What, do you cut a hole in the side of the microwave to admit the stave?

[vinemaplebows]

Front to back, stick the stave through the holes, wet towels to put around the excess, to seal the front and back. I found a older model with a manual dial, this way you can start the microwave at a distance with a extension cord......set your time (depending on wattage) start at 2 minutes, move up as needed. You must start bending within 2 minutes, and DO NOT repeatedly cook the wood as you will dry it out making the wood brittle. Let wood reaclimate for a day before you continue any major bending. I can bend in just a few minutes what it would take hours any other way.

This is NOT a joke, this is how I bend my staves, and have been doing it fdor several yrs. If you are afraid of this method.......you should really rethink eating that microwave popcorn at night.


VMB

[stuckinthemud]

Wow VMB, that's very creative! I tried a ruse I'd had limited success with on some small diameter yew once. I wrapped the area to be straightened in an old tea-towel then poured boiling water over it for a few minutes - it warmed the wood just enough to tweak into line  - the method is not man enough for most jobs but might be OK for this one.  The limb is straight at the moment but if the timber remembers its old shape then I will try steaming it.

[Chadwick]

Hey Stuckinthemud -- It sounds like you waterboarded your stave with hot water until it would cooperate? Some things work anywhere.

[stuckinthemud]

If anybody says anything I'll deny everything and ask for any incriminating comments to be removed from the records!

[stuckinthemud]

Hi VMB, so do you use full power with the microwave? I sometimes season timber in a micro but only use the defrost setting - as soon as the timber starts to steam you turn the micro-wave off and let the timber cool down, keep monitoring the weight of the wood on the heating/cooling cycle until the weight reaches a constant level and the seasoning is done. You can fully season green timber in an afternoon this way, but only if it is small enough to fit in the microwave!

[vinemaplebows]

The wood is cured before any microwave bending, and yes, full power.

[mullet]

Micro wave works great, I use it too. Just like steam bending but as fast as a TV dinner.