Osage and Dry heat? Revisited

[bradsmith2010]

if the stave is not dry enough,, the oil might help

[Pappy]

Guess we will just have to agree to disagree , I have had problem with checks on the back even with dry wood especially if they needed much correction, but with oil on the bell, seal the back and heat slow I have had none so for me it's not worth the chance.  once it happens it to late, it don't usually ruin the bow unless they run off the edge but just looks bad.

 Pappy

[bentstick54]

This is the 3rd one I’ve had this happen on. Bows are shootable, but i would like to figure out what’s causing this and how to prevent it. These have all been staves that I have kept avoiding due to twists and bends. I finally decided it was time to try and learn how to straighten them. (Ran out of straight staves). I think all of the above advice definitely has merit, and the 1st 2 where only 2 years in storage, taken down to a thin layer of sapwood, sealed with several heavy brushed on coats of shellac. I chased them to a clean back ring but did not seal again before applying heat. These 2, I can agree were probably still had too much moisture in them. The 3rd one I really feel was dry.

Can I be applying the heat too fast, too hot, or too long?

I’m starting another one, another 10 year old stave, that I’ve chased the back on. I think I will seal this 1, then get it to floor tiller, and try oil. I’ve got nothing to lose. I no different techniques work in different areas, I just have to find one that works for me.

[Pat B]

I've always used oil when bending wood with dry heat. I believe it helps to prevent scorching, it helps hold the heat a bit longer and by doing so it helps the heat penetrate better. I have no proof of any of this but it has always worked for me. As far as adding shellac to the back when heat correcting, since I started doing this I don't get checks in the back with heat treating and like I said I've had staves that were in the dry for 10 years that checked when heat was applied for tempering or correcting. That is why any time I chase a clean ring on a stave or or a bow I seal the back, no matter how well seasoned it is.
 The only time I don't use oil is if I'm tempering the belly. Then I want the dry heat to scorch the belly to help improve the compression values of the wood. I do however seal the back with shellac beforehand.

[paulsemp]

I like to use oil on major corrections. I've done it plenty of times without oil also but once in a while I get a crack and like to blame it on no oil

[PEARL DRUMS]

Guess we will just have to agree to disagree , I have had problem with checks on the back even with dry wood especially if they needed much correction, but with oil on the bell, seal the back and heat slow I have had none so for me it's not worth the chance.  once it happens it to late, it don't usually ruin the bow unless they run off the edge but just looks bad.

 Pappy

Looks like we will have to arm wrestle next time we meet up

Hope you are well old friend.

[Selfbowman]

Ok bent stick if I under stood you your on twisted staves. I know you are a good bowyer. Working with twisted grain I’ve encountered this before. Only so much you can unwind the rope 🤠that why I don’t buy or cut them anymore. Sell  that to the snake lovers and go buy you some straight ones. 🤠 just funning guys. Pat may be right about where we live affects it. That’s kinda what makes us different.  🤠

[Pappy]

No Arvin that ant what makes you different    Pappy

[George Tsoukalas]

Sorry. I got confused. I use olive oil on the back when bending too. When heat tempering I just put oil on the belly.

[bentstick54]

Thanks for the compliment Arvin, but you must have me confused with someone else. I’m just a hobbyist bowyer. Probably 18 to 20 attempts, with 7or 8 that I would not hesitate to give to friends, 5 or 6 that needed a little superglue and a wrap on a lifting grain on an edge, and well 4 or 5 that I just cut up. I cut and split my own wood, just part of the journey for me. I have no desire to go into building and selling bows, or chasing flight records. I just like the gratification of building my own, shooting 3d, and hunting with them. I do admire you and the others that have pushed bow building and performance to the level you have, and the willingness to share your knowledge with us backyard bowyers.

I got the profile close today, cleaned up the back of scraper marks, and sealed the back with shellac. I’ll let it sit awhile before working it to floor tiller. Once I get started back on it, and start heat corrections I’ll update progress.

Thanks for everyone’s input so far.

[bradsmith2010]

if you dont have a moisture meter,, you are just guessing... if you having a problem,, there is a reason,,

[Eric Krewson]

I never get any checking on heat corrections, I don't use oil, I only heat a limb enough to get it moving. I use the "can I still hold my finger on the wood briefly" method of determining the temperature I want. 

I heat my limb in the channel of a piece of aluminum angle, this distributes heat really well, the aluminum soaks up heat, gets really hot and stays that way.

I do use wood forms as well and wrap the correction with tee shirts but still go light on the heat.

After I gently make the correction and while the wood is still clamped, I wrap the limb and the piece of aluminum in several tee shirts to let the retained heat in the aluminum soak slowly into the wood. I leave everything clamped and covered until the aluminum and wood return to room temperature.

My method is seldom a one-shot deal, it is bend, cool and check, bend, cool and check until I am satisfied with correction.

[bentstick54]

I agree Brad, I’m just guessing, but trying to make educated guesses lol. I need to pick up a moisture meter rather than winging it, but just haven’t been trying any serious heat corrections until recently, so has not been a problem in the past.

When searching the internet for pin moisture meters I see them starting around $13 and going up from there. How expensive of one would everyone recommend for just an occasional user?

[bentstick54]

Thanks for your input Eric.

[bjrogg]

Totally agree with Pearl on the to much moisture yet.

I do alway seal my back on any wood as soon as I first expose it. No matter how long it’s been cut. I’ve had staves that were aged when I got them and left with the bark on for a couple years before I got to them.

Chased a ring on them and the next day they already had drying checks. I had a quite a few that checked on me before I sealed the back. Never really hurt the bow, but some people don’t like the look of it.

It’s not just dry heat either. I’ve had it happen with steam to.

Bjrogg