Heatbending self bows

[Lee Lobbestael]

Hey guys, At my work we have a big oven that I can set to any degree I want. When I put reflex or recurves on my self bows I use a heat gun, but to put reflex deflex into a whole bow this is difficult because it takes a long time to heat the whole limb. Could I use this oven to heat the whole bow before putting r/d? If so what temp and for how long?

[Eric Krewson]

I tried cranking up the heat on my drying box once to see if it would speed up the osage bending process, didn't seem to.

I have found that a good heat reflector will cut the heating time in half if not more. I use a piece of aluminum angle.

 

[DVSHUNTER]

lee I don't see why you couldn't. I put my staves right next to my stove. As for temp, I would set it at about one ffty and use an old piece first to test. I would say ten minutes would be good. Don't forget the gloves!

[Pat B]

When adding reflex to a bow I start at the handle and work out each limb, separately, is small sections and clamp each section as I go. When done with one limb I start at the handle and work out the other limb. I can usually get the entire bow reflexed in an hour or less, depending on how much other straightening it needs.
  I have tried clamping a stave to a caul and placing it in a hot,up to 186deg(F) that the thermostat allows and holding at that temp for a few hours. Then let it slowly cool over night. I have had limited results with this method and don't use it any more.

[bigcountry]

Originally posted by Lee Lobbestael:
Hey guys, At my work we have a big oven that I can set to any degree I want. When I put reflex or recurves on my self bows I use a heat gun, but to put reflex deflex into a whole bow this is difficult because it takes a long time to heat the whole limb. Could I use this oven to heat the whole bow before putting r/d? If so what temp and for how long?

What kinda oven is it?  We use thermatrons here at my work to burn in electrical components.  We can get em to 80C.

Don't think its enough for wood.  Not sure however.

[Lee Lobbestael]

Its for bakingelectrical components and drying epoxies and resins and stuff like that. I can get that thing to 200 F if I need to!

[ALW]

I do like Pat B does.  Clamp at the handle and heat a little at a time and clamp that section.  Then move to the next section.  Has anyone tried putting something like tin foil on their caul to help reflect the heat?  May make heating a limb a little quicker.

Aaron

[Pat B]

On thicker sections I sometimes wrap a heated section with tin foil for a few minutes to allow the heat to sink in before reheating and clamping.

[DVSHUNTER]

I have thought about the tin foil. I will try it and see if it helps me.  Pat, any theries as to why heatin in the oven didn't work well? Not hot enough? Just curious. Ihas good luck next to my stove. Interseting.

[John Scifres]

I don't know what the temp needed is but 200 doesn't seem like enough.  I can touch my oven rack when I dry jerky and I do that at 200.

When I bend wood, it has to get so hot that I can't keep my hand on it for more than a second.  Not scientific I know but effective.  

I suspect several hundred degrees would be needed in a baking situation to really get the plastic feel you get with localized heating with a heatgun.  

Now what I know works better is to do heatbending in warm conditions.  If I had access to a big oven, I think warming (preheating if you will) it up and then doing localized heatbending with a heatgun would be very efficient.  I often preheat a stave with the gun as I go.

[Lee Lobbestael]

Hey guys I found out that oven can go up to 400 F! Would that be hot enough? and for how long?

[Pat B]

I think like John said, as a preheater it would be fine. I don't think it gets hot enough plus the localized heat the way I do it concentrates the heat where it is needed, when it is heated. It doesn't take the wood very long to cool down so by the time you have it heated and ready to clampo it has cooled some.
  I don't know what temp wood scorches but a heat gun will get it to that or just below that heat pretty quickly. 1000deg(F) possibly?

[ranger 3]

Listen to Pat and John they know what they are talking about. It works

[John Scifres]

It sure can't hurt to try 400.  If you could fit a caul in there with it, that would be ideal.  clamp it loosely when cold and then cook it for a while.  Maybe 30 minutes.  Then tighten the clamps a little and see if it bends easily.  If not, cook for a while longer then tighten some more.  Then cook for a while longer until your clamped tight to the caul.  Sounds like fun.  Got a fire extinguisher?  Insurance?  

[NightHawk]

hmmmm  water boils at 212 f correct?? and steam can be used to bend wood? I'm thinking the tempature doesn't need to be so high in order to get the wood bendable. something to ponder about

[John Scifres]

I got to rememberin'.  Seems to me someone asked this question years ago.  I remeber cooking a small osage bow in my oven.  Con't remember the details but do remember I got it to bend.  

Good point Joe.

[macbow]

Hi all, I just attended a short seminar by Mike Yancy. On his short Osage bows He will sometimes sit a couple of pieces of angle iron on his wood stove and preheat the stave before using the heat gun and caul.
Ron

[razorsharptokill]

What if a stave is over 7 years old with the bark and sapwood off? Will dry heat still work to bend it?

[T Folts]

Steam and dry heat are two different things. I believe it would take alot more time in an oven compared to steaming at the same temp but I am not sure. Also after steaming you need the bow to set for 1 or two weaks to dry back oyut before tillering.

[Bow-n-Head]

I'v have very good results bending dry & wet staves in my heat box (160 F). I have a steel bow mold (caul) that I clamp my stave or "squared-up" blank to. Cook for about 2 hrs. & let cool over night. Puts in about 2 1/2" of reflex.  Works for me.