First Experience Heat Bending

[alcot]

Got my hackberry stave worked up pretty well, started to bend just a little bit. It had a twist in one of the limbs so I followed Jim Hamm's instructions and steamed the limb prior to bending it. Steamed it for 1/2 hour and it didnt seem to have an effect so I steamed it for another 1/2 hour. Whole garage was like a steam bath. Put it in a vise and used a large padded cresent wrench to twist it straight, although the wood was barely more than warm. Well maybe I got the twist out a little bit, but now the whole limb is way bent toward the belly--relfex I believe its called. Plus it is bent to one side. Plus there is a divot on the back where I used the crescent wrench--dont think I'll ever do that again.
I must say I'm a bit discouraged with my first experience in steam bending wood. I hesitate to steam heat the other limb for eveness.
What happened!!!? Did I do something wrong?

[huisme]

I use twine wrapped several times around the limb and pull no the ends to twist, try to keep metal off the back as much as possible.

Bend toward the belly is called deflex, the opposite is reflex

It's easy to accidentally push a limb the wrong way while you're not paying attention while steaming. It's completely possible to steam again and undo the deflex, though you'll have to be very careful with that divot-- I don't know much about hackberry, but you might have to chase a ring to fix that.

[Del the cat]

You need to contain the steam in something insulated  to keep it all hot and you need to apply the force ideally while the steam is on the wood.
Remember steam is invisible... the cloudy stuff is water vapour... clouds are not hot!
You can't mess about getting it from steam to bending jig, you have just a few seconds to do it. That's why I try to steam it in situ on the jig, and apply foce while it's still in the steam. This isn't always practical, so sometimes it get it out of the steam ond onto the jig, but don't take more than 10 seconds!
Also if steaming for 30 mins didn't work, then steaming for 30mins again isn't going to work either! It prob needs 45 or 60.
Here's a post fom my blog, it even has a little video of me steam bending some maple .
http://bowyersdiary.blogspot.co.uk/2012/09/steaming-bending-maple.html
If you don't believe steam bending works, try what I did in this post... tie a brick on the end of the bow and leave the other end in a steam chest. As it heats through you'll see the brick slowly start dropping as it pulls down the limb.
http://bowyersdiary.blogspot.co.uk/2012/02/spot-of-steam-bending.html
If you search for 'steam bending' on the blog there are loads of entries.
Del

[PEARL DRUMS]

Skip the steam and use dry heat rom a heat gun on high, hold it 4-6" away and get it hot enough you cant hold your finger on it at all. Move it and clamp it down w  padded c clamps or bar clamps, which I prefer. If you don't have a caul or form. Just use a 2x4 or your bench top and clamp it flat, give it about 30% over bend, some will come back.

[alcot]

Thanks for the information gentleman. This site is a wealth of knowledge.  I am enjoying building my first bow immensely and will give the bending another shot.

[bubby]

this is how I heat and take out twist and do alignment adjustments, floor heater clamp bucket of rocks, works pretty good

[alcot]

Tried the heat gun. Wafted it back and forth over the twisted limb for an hour, but it didn't get much more than warm. Maybe I can't do 30 inches at a time. Maybe I need a bigger heat gun (1300 degrees). Ain't got the hang of this bending business.

[Pat B]

I usually work a heat gun along a 6" area until it gets hot enough to clamp and move down to the next 6". I also go  back and keep the previous area heated until the complete limb is heated and clamped. I hold the heat gun about 2" to 3" from the wood surface and keep it moving. When I can't keep my thumb on the heated area it is usually hot enough.  I also use cooking oil on the wood while heating to straighten. I do this to prevent scorching, I think it helps hold the heat longer and allows it to penetrate better.
 When I heat temper a belly I do not use oil, just heat until chocolate brown and I use the same heating technique. 

[Badger]

   Hackberry is the easiet wood to steam bend out of all woods, it will bend in circles. You didn't get it hot enough or make the bend quick enough. You have to move very fast. As Del said 10 sec or less.

[Pappy]

I don't steam bend a lot but when I do as others have said speed is the answer and of course steam it long enough. I have my plan together before I start,I cold bend usually on a form and have everything set,clamps/shims/pads for the clamp all pre set before I pull it out of the steam and a heat gun ready in case something is taking to long. It's like a Rat race when it comes out of the steam tube. If I am doing a complete bow I try and have someone with me to do the other limb.  I like dry heat much better because of the  time control and do about like PatB/Pearl said. 
  Pappy