Primitive Archer
Main Discussion Area => Bows => Topic started by: PEARL DRUMS on December 28, 2011, 08:50:27 pm
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That has been asked a million times. The standard reply is "no". I answered the same way to a point. I have heated up fades in the past and pushed a handle back to gain draw weight and move my tips forward. It worked every time I did it and the bow didn't get any worse. I had a 64" snakey Osage bow with 4" of set, and 57# @ 28". It was an early bow and I rushed the tiller and over stressed the bow badly. After two cups of Joe I headed to the shop to do battle with this experimental bow, what did I have to lose? I scraped the skins off the back, removed two sinew bands I had holding wind checks in place and removed the grip. I sanded and scraped the whole bow clean and smooth again. The first thing I did was literally remove half the weight on the last 10" of limb, she was a bit robust to say the least. I lost about 3-4# of draw by doing so. I rasped the fades allot and got them moving properly. I lost another 3-4# doing that. I scraped both limbs evenly after I got the tiller corrected. By the time I done and the bow was all sanded smooth with 80 grit I lost a total of 12# in draw weight..............I still have that 4" of set I began with. I clamped her down the my 4" full relflex caul and set to work with my heat gun bending and forming the bow to the form. The instant I shut the heat gun off I darted outdoors with the caul and bow in hand and sat it all on our back deck to instantly chill in 25 degree temps. This was an experiment of sorts to see if "flash" cooling would impact the bow or the forming at all. I let it sit outside for 4 hours and then brought it in for another hour to acclimate, it was actually sweating a tiny bit. I inspected the bow top to bottom for cracks and found none, except for the two wind checks I started with. I un-clamped the bow and to my total suprise it held more reflex than any other bow I had ever built off that form, which is a bunch now. I strung it about half brace and let it sit for 15 minutes. Then I pulled it to 20" several times over letting the wood removal take effect. I went out and shot it 20 times @ 20" and came back in and unbraced it, it held 1 1/2" reflex right away..........wow. I waited a half hour and braced it fully. Went out and shot another 20 arrows at 24", came in and unbraced her and the same 1 1/2" came right back in a snap.I braced it back up fully and went out and shot 20 arrows at 28" and came back in, unbraced her at she held 1" of relflex. Its been an hour unbraced and its back to 1 1/2". Several things happened today for me. I BELIEVE the flash cooling may play a part in holding my new shape more firmly, I BELIEVE that I removed enough over stressed wood from both the back and belly that the bow was able to be retrained. All in all I lost 5# of the original draw weight and gained at least 5-8 fps, quite impressive to me. I'm sure a few hundred shots from now it will lose some more, but it wont be nearly as bad as what I started with. I made up nearly 5" of tip movement alone. If you read this WHOLE bit, please feel free to comment, politely argue or discuss!
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Do you think the 'sweating' helped rehydrate it that fast. I would have expected it to blow with bracing that soon after heat bending.
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Pearlie I will comment if you will bear in mind that I not only don't know much
but that I am happy with that. I BELIEVE that the wood removal and heating
of limbs on the caul changed the internal dynamics of your bow wood. Like
you said, you maybe removed the damaged "set" wood and basically heat treated
over what was left.
I would think that cold treating would keep the wood fibers in a state of
suspended animation ( frozen ) with little change.
Your bow changed but I think it was more skill than chill.
Lane
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Do you think the 'sweating' helped rehydrate it that fast. I would have expected it to blow with bracing that soon after heat bending.
Nope. Rehydration is much deeper than surface moisture. That was just something I noticed. Hot wood plus cold air equaled moisture.
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Drums: I suspect that you experienced the benefits of both heat treating and making better efficiency of your bow mass. I suppose that I have a few additional questions:
1. Did you heat the belly wood enough to "tan" the wood?
2. Did you clamp the entire limb all the way to the reflexed caul prior to heating? OR... Did you just clamp the limb tips and gradually clamp the limbs to the caul as you progressed down the limbs with the heat gun?
3. What bow design did the original bow have? Pyramid? Parallel? Paddle?
4. What bow design did you end up with?
5. When you removed wood, did you remove any from the belly or mostly from the sides?
6. Was the bow heat-treated originally?
I think that it was a very worthwhile experiment on your part and a way to bring new life to some of our "dogs". It is discussed in TBB4 that heat-treating changes the cellular composition in the wood. I would suspect that if you tried to improve on a once already, heat-treated bow that your results would not have been as positive.
Bring the bow to Marty's in January. I'd like to see it!
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Good questions Matt
1. no
2. I clamped the handle and heated my way to the tips. Clamping as I went.
3. Its a wierdo bow, all mine seem to be? The top is snakey and parallel while the bottom is pyramid like.
4. Same design, slimmed down.
5. I removed 97% of the wood from the belly and 3% from the back to clean it up and round edges better.
6. Nope, only steamed and cauled. No dry heat.
I plan on bringing bunches o' bows Matt. Makes me wonder just how many chips will even be made with all the shooting going on??
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I copied n pasted what we were talking about in email here so folks can see publicly what I think about it.
Here's my take on it. But first off..simply said...yes you helped that bow out. N once a bows not used anymore or retired then why not experiment with it....good job.
So, I don't know if you remember mikekeswick posted an experiment with a bow that had a few inches of string follow(set) in it. He cut it lengthwise down the neutral plane. The tension piece snapped back to normal where it was before it was made into a bow. And the belly piece remained in string follow. The set and compressed cells on the belly held the wood in string follow,and once he cut it the tension side was released from the forces of set in the belly. Interesting stuff. So, I think if you remove some of those bad cells(the worst are at the surface),and retiller and reheat treat it you then can gain a bit back. But I still don't think you gain it all back. There's just too much belly wood that would have to be removed to take it all out,and you'd end up with a kids bow before you got it all out.
As far as going from hot to cold,I have no clue what that will do,or help enough to know or see a difference. It never hurts to try something new tho. I have thought of that before,and ill apply cold acetone or denatured alcohol over a belly right after heat treating it just to cool it down faster so I can work on it sooner.
And yeah I've bent wood less than 24 hours after heating it with no problems either. But id rather be patient and wait,but its hard to do that ;)
Unfortunetly im working 3 days this week. If were not moving this weekend im hoping to
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I wish I had a secretary to keep track of my experiments over the years !
I would heat treat the belly yet and finish it up!
As far as success removing set goes I do think it depends on what was already done to the bow!
Have fun
Guy
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Interesting experiment but I seriously doubt there was any "flash" cooling and I don't believe there are any benefits to quickly cooling a bow anyway. I remember heat-treating some bows during the Winter many years ago and using snow to cool the belly, the temps up here get considerably colder than 25 in the Winter. There were no apparent benefits to doing that and the cooling process was no doubt much faster than just bringing the bow out in the cold.
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I wish I had a secretary to keep track of my experiments over the years !
I would heat treat the belly yet and finish it up!
As far as success removing set goes I do think it depends on what was already done to the bow!
Have fun
Guy
I'm glad you said that. It just gave me the idea to start a journal containing the details of each attempted bow. I think that would be worth my time to maintain.
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The bow is back to the original 1 3/4" of reflex after resting over night. Its hard for me to say that the cold didnt make a difference. This is food for thought next time somebody asks if set can be removed from a bow. Maybe the standard answer shouldnt be "no"? As with everything we do regarding this hobby, there are a million variables. The pic below was after another 20 full draw shots last night.
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I think you just got lucky Pearly ;D.
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I would rather be lucky than good any day Artsy! This stupid experiment hit me like a brick Im telling ya'. The bow went from worthless to a favorite in 6 hours.
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Now that's my old saying Pearly, so don't you be taking it >:(! Gotta love Osage ;D! Interesting............but be sure to let us know how the marriage is going after the honeymoon effect wears off ;D.
What's the growth rings look like in your bow, big or small? Larger rings seem to benefit more from heat treating than the smaller ones I've noticed.
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Top half is only one and a half rings thick, the bottom limb is four rings or so.
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Great experiment man!!! Too much people too much time answered with NO without personal expirience about it.
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Great experiment whether it's the exception or the rule... success and new life for an old bow!! I don't know how I would accomplish the cold except maybe the beer box a the local Liquor store.... for me every new bow is an experiment but I have another thread to save in my fix it files...
Cool stuff Drums :)
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Great experiment man!!! Too much people too much time answered with NO without personal expirience about it.
We will never see a TBBV if we dont think outside the box like the authors did on the first four volumes Druid! Whether this worked/works or not, I can still check it off the list of things to try. The bow has been shot almost 80-85 times at full brace, full draw. Still holding a tad under an inch of reflex right after unbracing. I just dipped half the bow tonite, the other half will be done saturday. The three days to dry after that. I will get back to plinking away and checking back in with numbers. It should be fun to see what does or doesnt change, I hope she holds strong!
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Awesome discovery.. Just goes to show it never hurts to go out on a limb and try something new. nice
Jon
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Pearl
I have said it before bent wood is not necessarily collapsed cells , most of the time bent wood is just bent wood !
bend it again and go on!
There are times that you may not want to ,
no is not my standard answer !
Guy
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Excellent post!
A well documented and well constructed experiment, it's this sort of thing that moves our knowledge and experience forward.
Re working our early bows, is like started with 90% of the work done which certainly saves some effort. It also shows us how our bowmaking has progressed.
This gives us all 'permission' to try more radical stuff.
Nice one.
Del
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PD, good thinking. You are moving towards pHD level now by attempting to discover something new. 4 inches of set means your wood was probably wet? The experiment needs to be repeated by you and some others, though, before we can draw any lasting conclusions. Seems that a couple of factors could enter into the change you observed. You heated on the caul and you chilled it. We don't really know which of the 2 factors caused the change. Did you mention if you tried reversing set on the caul and letting it slow cool? I did read the whole explanation but may have missed it. I have cut set by reflexing the last 6 inches or so. But I could not use this method. The "dashing" outside would get me. By the time I got out there it would have slow cooled anyway.I wish I could have seen your mad dash to 25 deg F temps. :) Jawge
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George Im thinking the amount of wood removal and reheat are the reasons it staying so far. I think the cold didnt do much more than allow me to shoot the bow 5 hours later rather than 24 hours later. I cant prove or disprove the flash cooling helped. None of us can really. I have tried this with gradual cooling in the past and had okay results, but those bows had much less wood removal prior to reheat. The stave was dry actually. I just bent it too hard, too soon, too many times! But thats all I did wrong......;)
I make mad dashes around here all the time. Steaming recurve tips or a whole bow. Some day Im sure I will break something! I bet my darting through with a 72" 2 x 8 form with a bow clamped down was a sight.
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Most of the nay sayers about this sort of thing are just repeating something they heard someone else say and don't have any first hand knowledge one way or the other.
My advice would be to put the bow up and let it rehydrate for a month or so. Three times in the last couple years I rushed a bow with 15 or 20 heat corrections into service without letting it rehydrate for a few weeks, every one of them developed a fatal crack.
I give my severely heat corrected bows a grace period now before I do any serious shooting with them, haven't had any unexpected cracks since.
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I'm thinking that experimentally you don't know which factor influenced the change until you isolate your variables. But I suspect you may be right. But on the other hand, you did shift that neutral plane around by your wood removal. Bows usually react with an increase in set when bowyers do that.For example, string bows that are too heavy=add. set. Something has to account for the set reduction...the caul or the flash, mad dash cooling. Jawge
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Eric, is right. I just heat corrected out a prop twist in a red oak stave and let is set for a week before continuing. The darn thing will probably break anyway. :) Jawge
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Most of the nay sayers about this sort of thing are just repeating something they heard someone else say and don't have any first hand knowledge one way or the other.
I agree Eric. I read TBBI & 2 and could answer any question asked......according to the books and not something I actually tried. I try not to post that way anymore unless I make it clear I have zero experience and Im just throwing some opinion around.
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Eric, is right. I just heat corrected out a prop twist in a red oak stave and let is set for a week before continuing. The darn thing will probably break anyway. :) Jawge
Probably right Jawge............stupid red oak...;)
The bow was half dipped last night and the other half will be done Saturday. It will have at least 6-7 days to relax before its gets braced up and shot to DEATH! Only one way to find out what is what. Keep in mind it wasnt tempered, just warmed up enough to form it. So rehydration may not be as lengthy.
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Keep pressing on Pearl !
I enjoy reading about your adventures !!
So good to see someone excited about finding out for themselves !!
You may even inspire me to get of my Lazy duff and do something different !!
(now where is that old lemon wood bow anyway? Maybe if !!)
Guy
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Nice post! Im trying a similar rebuld on a short hickory. I did not try reflexing just heating out some set on a flat 2by, I took out 50%some or more. I cooled it down with ice from my w7, I have not braced it yet and plan to back with linen, ill post that if it ever gets done ;D
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I've messed around with some of my hickory bows in a similar manner and discovered that I could fix string follow in a bow that had never been heat treated before. I recall one that had about an inch of follow, where I heat treated 4" of reflex into the bow, which brought the draw weight up enough that I could re-tiller the bow back to the original draw weight. After shooting in, this bow retained about 1/2" reflex and had a much better full draw profile. However, when I attempted to re-heat treat it back to the 4" reflex, I had to re-adjust the tiller a slightly, and it pulled right back to the 1/2" of reflex, but I did gain a couple pounds of draw weight. I think the only advantage I got from the second treatment was to deepen the effect on the spots where I had removed more wood adjusting the tiller. This was a straight limbed Eastern Woodlands style, and I had similar results with a Sudbury I made this past summer. I messed up a bit figuring out how to tiller that style, and was able to recover it through heat treating and re-tillering, then heat treating again where the wood was removed, then fine tuning the tiller. It does seem, from the first experiment, that heat treating is a one time thing, unless you remove a sustantial amount of belly wood and lower the draw weight.
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Julian how many shots did it take for your hickory to go back where it was? I removed quite a bit of belly wood and some off the back. I had skins glued on so clean up required some dust be made from the back, its still one solid ring. Great post Julian and thanks for the adding on with your experience.
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Sorry it took me so long to reply, I've been away from the computer for a couple days. It was a few years ago, but if I remember correctly, it only took about 20 shots for it to get back to its final unbraced profile. I posted the bow years ago under a different user name; I'll see if I can find a couple picks way back in the forum. That particular bow got ruined this past spring. At first I thought the lower limb crysalled from my kids stringing it improperly, and that may have contributed, but my 75# bow did the same thing whaen I pulled it out of my garage and shot it this spring. Now I suspect the high humidity of my storage location had more to do with it.
Jude
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PD
Found the old pics and downloaded them from the forum, but now they won't pass the security check to upload them again. If your curious, search for Brokestick, then look at the post for "Hickory Algonquin Replica". Looking at them today, I can tell the tiller was off and the top limb was stiffer than the bottom, which is the exact opposite of what you want. I'm surprised it held up as long as it did, but I suspect the hickory liked the Mojave humidity better than the Upstate NY humidity I moved it to.
Jude
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Im well past twenty shots with this bow. The finish has dried over the last three days. Three days ago one limb had about 3/4" of follow right after unbracing. Its gone now, the three day rest brought her right back straight. I plan on shooting it at least another 30-40 times today. I will post another pic this afternoon and we shall see.
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I think it will be interesting watching this unfold, or not. I braced the bow, let it sit for an hour and shot it about 60-70 times tonite. That puits me around 125-150 total. Unstrung, it bounced back dead flat. One hour later is the above pic at about 3/4" reflex, hopefully more to come. I posted the "hot off the press" pic as well, just something to compare it to. I did lose about 3-4#'s of draw re-shooting in this bow. It feels settled to me now.
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That's still waaaaaaay better than 4" of follow.....looking good so far. ;)
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Excellent Thread and a Nice Job documenting your process Pearl Drums.
The TBB IV chapter on Heat Treating (by Marc St. Louis) bears out some of your findings and definitely your results in a fashion.
Heat Treating can breath new life into an Old War Horse allowing the Overhaul to reduce Mass and induce sustainable Reflex while gaining draw weight.
Looking back through this chapter, I recall (but can't find at the moment) that a bow can be RE-Heat Treated with some success as well.
-gus
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I often heattreat my old bows with a lot of set into some reflex. Most of theme are after retillering straight or had just a bit of set.
Most with Hickory or Elm.
For me there is a clear "yes" of removing set from an old shot in bow.
Greetz
Cord
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Well after a few hundred more shots Im calling this case closed. The bow hasnt budged from what you see in the above pics. It settled in with 1" of reflex after about a one hour rest. Keep in mind I didnt heat treat this bow at all. I only used dry heat to form and re-form it to my caul.
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Good save Pearl !!
I think we need more words in our vocabulary of bow terms !
Because as I have said before often times "set" is not "set" at all, just bent wood, so bend it again!
Guy
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That's a good point Buckeye. I think the next time I have this situation, I'll heat it back into reflex and retiller, but not heat treat until the tiller is perfect. I think the heat treating was most useful in giving me back the draw weight I lost in retillering the bow. I plan on taking the 75# bow that hinged and crysalled on me last spring and seeing if I can dig past the fractured wood to a 50# bow. Should be an interesting experiment. That was my first shooter, and it held up well in the desert, but didn't do as well in the east coast humidity. That's where my tillering errors became painfully apparent.