Primitive Archer

Main Discussion Area => Bows => Topic started by: JW_Halverson on September 22, 2008, 10:32:51 am

Title: bending old wood
Post by: JW_Halverson on September 22, 2008, 10:32:51 am
I have a verrry old osage stave that is on the way to becoming an ELB (and maybe an article for PA).  I have a lateral dogleg in the handle area and I am concerned about straightening.  I wish to avoid the usual cracks associated with steam and the scorching I seem to always get from using a heatgun.  The stave has been sitting in a roughed out stage all summer in hopes that it would take up a little moisture from the air, it started at 4% moisture in May and is up to 6% now.  Any suggestions for a more gentle technique for heating a stave for bending?
Title: Re: bending old wood
Post by: adb on September 22, 2008, 10:56:51 am
As far as moisture content goes, I like to keep my wood at about 9-10% just before I start to tiller it. Too wet, and it takes a lot of set, too dry, and it becomes very brittle.
Some pics of your stave would be great, so we can see what you want to straighten. When it comes to bending wood for me, I stick to the old rule: dry heat for dry wood, moist heat for wet wood. If you're scorching your wood with dry heat, try saturating it with some veg oil before you start, and don't get your gun too hot, and keep it moving all the time.
Title: Re: bending old wood
Post by: DCM on September 22, 2008, 11:00:56 am
Hold the heat gun farther away, and soak for a longer time.
Title: Re: bending old wood
Post by: JackCrafty on September 22, 2008, 12:19:43 pm
Osage doesn't like dry heat...or being too dry (although it will probably bend just fine this way).  I would try the steam.....and try to keep it in the steam for just as long as required, not more (this will reduce the chance of cracks developing).  You'll have to take it out of the steam every few minutes and try bending it.
Title: Re: bending old wood
Post by: JW_Halverson on September 22, 2008, 04:52:26 pm
I'm avoiding adding any oil to the bow because I am down to a good growthring on the back, would hate to chase another out. 

I do have an idea involving an oven, 50 lbs of sand, a cardboard box, and a little more patience than I was granted at birth...if it works maybe it would be another article for PA. 

Lastly, about what temperature should the wood be at before attempting the bend?  I have heard the 400 degree benchmark mentioned, but that is getting pretty close to the ignition point, remember Fahrenheit 451?

And thanks for the input, everyone!
Title: Re: bending old wood
Post by: Justin Snyder on September 22, 2008, 05:20:01 pm
Osage doesn't need to get near that hot.  I would wipe it down with Crisco and use a heat gun.  Yes it leaves a little oil on it but I like to degrease Osage with acetone before finishing anyway.  If your wood is real dry and you put the steam to it you better have it sealed good with lacquer or varnish or it will check.  Justin
Title: Re: bending old wood
Post by: Badger on September 22, 2008, 07:16:56 pm
I have never had any wood drop below 6% where I am at but prefer to have my wood close to 10% and not less than 8% when I am using dry heat. Below 6% I think osage could easily crack when heat bending, I could very well be wrong but seem to have better results with a slightly higher MC, Steve
Title: Re: bending old wood
Post by: Pappy on September 23, 2008, 05:52:09 am
JW you must be in a really dry area for it to be that low,I usually use dry heat on barn dried
Osage if it is over 3years old and steam on anything younger than that.I never steam but once
and if it needs more tweaking I use dry heat from then on. :)
   Pappy
Title: Re: bending old wood
Post by: GregB on September 23, 2008, 08:55:56 am
You might try applying the vegetable oil only to the belly where you'll be directing your heat, I've done that with good results...