Heat correcting failure (success!)

[LivingElemental]

Im going to write this off as my own inexperience, and hopefully not sheer stupidity.
Using a heat gun, high setting, heat treating 6 inches or so of twist out of the tip of a limb.
I heated up the wood in question until it was far too hot to touch, tried twisting it, and nothing happened.

All ive managed to do it scorch the belly of the bow, and nothing else.
Ive been reading walkthrough after walkthrough, and can't find out what ive done wrong.

Help an idiot out.

[tanner]

I'm just a no0b myself, but I believe my first failure.... I meaning learning session... with heat bending was plagued by a limb that was too thick. Anyway - I know thickness and wood type have a lot to do with it. I've also heard some conflicting views on whether or not you should use vegetable oil (helps protect from scorching, spreads the heat, etc but also can cause issues with finishing if you don't get it all off). Anyway - it might help if you post pics along with the dimensions of what you're trying to bend and wood type. 

[Carson (CMB)]

It is not about the surface temp. You have to get that wood hot through the middle. Turn that heat down to med-high, then find a way to position the heatgun safely, so that you can leave it be for 1/2 hr.  then give it a test, if it is not agreeable, heat another 15 min., then try again. 

I like to use a quickly made aluminum foil heat shield to reflect heat back to the side opposite the heat guns heat. 

And what Tanner said 

[Del the cat]

I'd suggest getting an off cut of wood say 1" x 1/8" and try heat bending that to get a feel for it.
The usual problem is not allowing enough time for the heat to penetrate.
My personaly view is that for big stuff steam is better if you can build a box round the bit of limb to be bent (foam insulation board or a plastic 5L container can make a makeshift steam chest) and pip in the steam from a wallpaper stripper or some such. Give it 30-40 mins and you will know the heat has soaked in (in the early stages the steam condesing into water droplets dumps it's latent heat of vapourisation into the wood). Steam also gets right round the wood , which is harder with a heat gun.
Impatience is you biggest enemy... Oh and the zombies...
Del

[osage outlaw]

What kind of wood is it?  Slow and steady with the heat.  If you scorched it, you are doing it wrong.  I like to keep the heat gun about 8"-10" away from the bow and keep it moving back and forth constantly to prevent scorching.  I always use the high setting and mostly heat osage.

[LivingElemental]

Its the one persimmon bow ive been working on for a while. i would like to think it will bend just fine without the heat correction, but i don't want to risk snapping the tip off. i had heard someone say heating for 10-15 minutes on high is.all that you need, but perhaps i need to set it up for a longer period of time. Ive got it down to floor tiller, so thickness shouldn't be the issue. I'll keep trying.

Boiling isn't really an option at my house. the wife is overly cautious about everything.

[Dean Marlow]

I will put a small pipe wrench  on my bows then slowly heat it up while putting a little pressure on the pipe wrench when she is ready to move you will feel it give. Dean

[bobnewboy]

The pieces I have straightened have always been with dry heat.  All I do for prep is to take any sharp edges off with coarse sandpaper to prevent any chances of wood fibres catching alight, and then put olive oil all over the piece to be bent or straightened.  Then be patient and heat the wood thoroughly before trying to bend it.  The oil enables the wood to take more heat without burning, but you need to heat for a longish period so that the full thickness is ready to bend.

[Pappy]

I do like OsageO as far as heat gun setting,High. I usually put cheap cooking oil on white wood and be sure the stave is floor tillered,the easier it bends the easier it is to heat straighten. I know most don't agree but it don't take 10 or 15 minutes per spot for me.Maybe 15 minutes per limb. I usuall put it on the form clamped at the handle and then work my way down the limb clamping as I go and keeping the gun moving,I also usually pull the tips in before I start so they obsorb and keep pressure on the whole limb as I am working my way down the limb.Keep in mind I ant heat treating the limb,just straighting it. Usuall takes 30 minutes for a bow unless it has a lot of issues then a little longer.
   Pappy

[H Rhodes]

I agree with Pappy about it not taking so long to heat and straighten.  I don't have a heat gun, but do my heating on a stovetop.  I put the burner on high and prop the limb belly down about 4 or 5 inches above the hot stove eye.  When the back gets too hot to keep my finger on it for more than a second or two, it is ready to bend.    I think about six to eight minutes in one spot will do on a floortillered limb.  On the white oak that I have been working with lately, it smells like popcorn when it's ready to bend.  The belly will toast like bread.  You have to keep an eye on it.  Mr. St Louis said "brown is good, black is bad".

[George Tsoukalas]

A small amount of twist never hurts anything. I don't worry about twist unless it approaches 30 degrees. Check my site for removing twists. Jawge
http://georgeandjoni.home.comcast.net/~georgeandjoni/fixtwist.html

[BowEd]

Diddo on what previously has been said.I know hickory is more stubborn to dry heat bend than hedge.Persimmon to me is close to hickory in my book.Maybe you can get a turkey fryer outside and boil it and clamp it to the form.After that's cooled and dry[a week at least] just heat treat the belly a bit and it won't pull out as much later.Done this with hickory quite a few times and it really works great.

[gutpile]

if removing a twist I use a heat gun on high hold about 8 to 10 inches from wood and run it back and forth over twisted area till it is too hot to hold for a second...then I quickly wrap with leather pad or glove just to keep from denting the wood and twist with a pipe wrench...and I hold it beyond the amount of twist back I need till it roughly cools to the touch about 5 minute maybe..more like 3 .....if more is needed I redo...I don't want to scorch the wood...maybe a light hue but we are not heat treating it...after wards I like to let it sit a day or two before stringing...if you do it too fast the wood can check if it still has some moisture in it...gut

[Will H]

I second what pappy said

[LivingElemental]

Okay we're in business. clamped the bow down to my deck railing, then put a c-clamp on just the tip that needed untwisting. Lathered it up with vegetable oil and started heating it. 10 minutes of heat, applied force, and let cool for 5 minutes. Keeping the whole thing clamped down overnight to make sure it stays.

thanks all for your input.