Primitive Archer
Main Discussion Area => Bows => Topic started by: half eye on May 29, 2016, 11:12:28 am
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Hey fellas,
Been several discussions on here about steam bending wood. Well here are 3 examples of steam bent wood that is more than 100 years old.
In the pics there are 3... 1/2 wheel rims...these were made and kept as "repair" parts. The top one is for a buggy and is about 1-1/2" X 1-1/2" white oak.
The second one is a heavy cargo wagon rim and is about 2" X 4" and made of white ash. The third is a general duty wagon wheel and is about 2" X 3" and also of white ash.
The rims have been stored in an "open-air" wood shed for the past 30 odd years and in a barn before that....There original shape has not changed enough to make them "not-useable" Steam bent wood will hold it's shape.
rich
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Great example Rich
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Rich,
I agree, steamed in reflex has worked great for me...No issues...Temperature is temperature internally...The thing I like about steam is it only takes 5 minutes on a 1/2" thick limb to bend like rubber...
Don
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Keep in mind that nobody has been bending these in the opposite direction though.
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yeah Pat,, :D
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Steam bent wood gives hornbows their shape and they keep it too. 'Enhanced' slightly by sinew but still :)
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Aren't you forgetting the horn being glued to the reflexed surface?
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PatM,
How about it? what do you think about steam? Got any positive info you could share with us rookies...?
Don
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I steam static portions of a bow.
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Don't forget there is also chemical bending of wood which is used commercially, although I don't know if they were using that method 100 years ago
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Aren't you forgetting the horn being glued to the reflexed surface?
Oh yes I forgot about that.....???
Do you mean the horn that is less stiff than the wood to which it is glued.....The shape of a hornbow is entirely reliant on the wood.
Do you have a point?!?
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Aren't you forgetting the horn being glued to the reflexed surface?
Oh yes I forgot about that.....???
Do you mean the horn that is less stiff than the wood to which it is glued.....The shape of a hornbow is entirely reliant on the wood.
Do you have a point?!?
You don't think it aids in holding shape despite its lower stiffness?
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Steam bent wood gives hornbows their shape and they keep it too. 'Enhanced' slightly by sinew but still :)
I'm a bit confused about that statement. All that I have read about hornbows, never have I seen mention of the core wood being steam bent before gluing the horn and I did not do this to the ones I have worked on. I"ll have to look at Adam's book again, maybe I missed something
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In Adams book he uses steam to bend his maple cores before glueing on the horn.
I think it's a perfect combo of horn, sinew, and core which allows a horn bow to keep its shape.
Although my bighorn bow with no wood core seems to hold its shape just fine
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Interesting Rich. I've noticed most of the Amish buggies around here tend to have round wheels too.
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my neighbor was Amish, he made rocking chairs from hickory,, he did some really nice steam bending,, I traded some of my turkeys for one,, :)
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They have a steel rim holding the wheel in shape.
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In Adams book he uses steam to bend his maple cores before glueing on the horn.
I think it's a perfect combo of horn, sinew, and core which allows a horn bow to keep its shape.
Although my bighorn bow with no wood core seems to hold its shape just fine
Does he steam bend the hard working inner limb?
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No sir he doesn't. And sorry Rich, didn't mean to get in on the thread hi jack
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In Adams book he uses steam to bend his maple cores before glueing on the horn.
I think it's a perfect combo of horn, sinew, and core which allows a horn bow to keep its shape.
Although my bighorn bow with no wood core seems to hold its shape just fine
Does he steam bend the hard working inner limb?
Do you mean the working limbs that need to be close to straight to reduce separation forces on the laminates??? How about the kasan eye?
Marc - yes the core must be steam bent into the desired shape before you glue horn. The wood is stiffer than the horn so the horn conforms to the cores shape. The horn is also heated prior to gluing to make it more flexible. The horn/core are then shaped and the sinew added.
My point is that the bows shape is held by the steam bent core. Obviously the wood isn't doing tension/compression 'work' but it does get bent quiet significantly and returns . If steam bent wood lost its shape we wouldn't bother steam bending wood.
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In Adams book he uses steam to bend his maple cores before glueing on the horn.
I think it's a perfect combo of horn, sinew, and core which allows a horn bow to keep its shape.
Although my bighorn bow with no wood core seems to hold its shape just fine
Does he steam bend the hard working inner limb?
Do you mean the working limbs that need to be close to straight to reduce separation forces on the laminates??? How about the kasan eye?
Marc - yes the core must be steam bent into the desired shape before you glue horn. The wood is stiffer than the horn so the horn conforms to the cores shape. The horn is also heated prior to gluing to make it more flexible. The horn/core are then shaped and the sinew added.
My point is that the bows shape is held by the steam bent core. Obviously the wood isn't doing tension/compression 'work' but it does get bent quiet significantly and returns . If steam bent wood lost its shape we wouldn't bother steam bending wood.
The working limb is not straight in many composites. You seem to be thinking only of Turkish bows..
The Kasan eye flattens. it does not "bend".
That's a good test to see if steam bent wood holds up in a working section. Make a wooden bow with a kasan eye or fully working recurve and see if it holds up by itself."
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Carry on everyone. It is hopeless to try and share information and get input so that everyone can be aware of different things (increase the knowledge base). There was nothing in my original post about ...."OMG, steam is the only way (or best way) to bend wood". Have a good time till ya run out of breath or piss.....which-ever comes first.
rich
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I have made several bow steam bending with out any problems, Ryan O use to be on here made many many working recurves steam bending and they held just fine, I do prefer heat when I can ,but steam is a very good option also. Some times I wonder about you guys. :-\
Pappy
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no worries Half Eye, thanks for sharing, I am learning as I am sure others have as well,, :)
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Carry on everyone. It is hopeless to try and share information and get input so that everyone can be aware of different things (increase the knowledge base). There was nothing in my original post about ...."OMG, steam is the only way (or best way) to bend wood". Have a good time till ya run out of breath or piss.....which-ever comes first.
rich
Aren't you getting input?
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My opinion on steam from a guy in the trenches is that it holds wonderfully...The inner cells of a limb reach a certain temperature whether your using a heat gun, camp fire, grill or steam...My findings is that steam is more of an even heat since it totally surrounds all surfaces, back, belly and sides without the risk of scorching. I have experienced set as everyone, but can't blame it on steam, a minimal amount is to be expected anyway...Here is my latest example and I was well pleased...I would really like to here others findings on steam results good or bad...Just covering steam bending here, no tempering...
The finished profile shows some loss of reflex that I blame on tillering stress...55@25, 51@24...Severe deflexed mid limb corrected by steam...
Don
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My opinion on steam from a guy in the trenches is that it holds wonderfully...The inner cells of a limb reach a certain temperature whether your using a heat gun, camp fire, grill or steam...My findings is that steam is more of an even heat since it totally surrounds all surfaces, back, belly and sides without the risk of scorching. I have experienced set as everyone, but can't blame it on steam, a minimal amount is to be expected anyway...Here is my latest example and I was well pleased...I would really like to here others findings on steam results good or bad...Just covering steam bending here, no tempering...
The finished profile shows some loss of reflex that I blame on tillering stress...55@25, 51@24...Severe deflexed mid limb corrected by steam...
Don
That "certain temperature" is potentially vastly different with each heating method.
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Pat, I am still learning ,, keep it up,, :)
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Whatever temperature it is, it works ;)
Don
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When you steam bend osage do you seal the wood first to keep moisture out??
And, can a 2" wide x 1" thick osage be steam bent ???
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Mad Max, some seal the wood before steaming, but not all do,,
your second question would depend on how much you want to bend it,, a slight adjustment ok, but something aggressive I am not sure about that,, someone will chime in that has more experience than me,, :)
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Mad Max, some say that sealing the wood before steaming is not necessary but I do seal(at least the back) with shellac. Shellac can handle the heat and moisture.
You can steam wide, thick wood but you have to steam it longer to get the heat way down inside the wood. I would reduce it to almost bow thickness to insure I get good heat penetration before bending.
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Mad Max, some seal the wood before steaming, but not all do,,
your second question would depend on how much you want to bend it,, a slight adjustment ok, but something aggressive I am not sure about that,, someone will chime in that has more experience than me,, :)
about 30" Radius
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Max,
I have steam bent wood the size in your question. My wood was not sealed ,and anytime I have steamed wood with some finish on it the steam has taken the finish off , or partially so, and the steam still penetrated.
On your 30" radius question, if you are meaning either a full circle or half circle....you would need a mechanical jig and a live steam table. If you are talking about a partial bend (like the limb shape of a sweeping recurve) then that is very doable.
The major enemy of steam bending is the time (temp loss) between steam and bending and how long it takes to complete the bend. A steam table pre-steams, and continues to steam throughout the bend. Most bowyers steam the wood, remove it from the steam and then move it to the jig, caul etc. And that timing (even seconds) is what can make or break the results.
Maybe that will help you some.
rich
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I use this method, modified slightly of course.
https://www.youtube.com/watch?v=--iPQIwSEJM
I use bread bags usually. Get it all set up and ready to bend, steam it, clamp it, steam it a bit longer and then cut as much of the bag off as possible and then I aim a fan at it to cool it off. Leave it overnight. I find that a steamed curve will hold-- most of the time. The other are just the wood gods keeping me on my toes. Dry heat after the fact does seem to set the curve.
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Yea a piece about 18" long
I will come up with something to keep it steaming while I bend it.
I saw that youtube once before
Thanks guy's
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Some woods like hickory bend better and hold their bend better when steam is used, in my experience.
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Cool thread half eye.
Very cool catch DC about that steam bending bag too.
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I got a question concerning steam. I steamed the bow that I am working on now to do some adjustment on straighteners and bend a little reflex in it.I didn't seal it. I ended up with some cracks in the wood that ran with the grain, they were not a result of any bending they were in the mid area and I didn't align anything there. Is it possible I just left it in box to long and dried it out to much?
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Cracks/checks are always wood drying too fast. Outer fibers dry and inner fibers have no air contact and aren't drying (or at least as fast). So something has to give = checks.
Halfeye - I hope I didn't offend you. I was merely adding another example of steam bent wood keeping its shape. It's not my fault that people have come back with comments that have little sense in them. If somebody says one of my statements is incorrect i'll always do my best to corroborate what I have said.
I'd love to have met the people who made those wheel rims - they would have had to have known their stuff to have been able to make them and anybody who is skilfully in making things deserves my respect.
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Arrowbuster,
If you subject wood to steam for long periods you are drying it out to nothing. What I mean is if you cover a piece of wood and steam for a few minuets the wood will look "wet", but you leave that wood in the same set up for 30min to and hour and the wood will come out looking "dry" Thats because the wet heat will actually "cook" all the moisture out of the wood cells if you let it....any wood that you completely dry in an hour is going to check.....so I am guessing that you may have steamed your wood to long. Another example of liquid drying out wood, is a technique that some Japaneese wood workers use to dry logs.....they leave one end of the suspended log in a movinbg water body (creek etc) untill it is cured out.
Mike, no sir you did not, the situation was exactly as you described it to be. I was trying to show some steam bent wood that has survived time despite being ill-cared for. and hoping to get others to share some of their examples of the process.
rich
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So I have always gone by the general rule of thumb that you steam for half an hour per half inch of thickness to bend. I use that rule for both getting an even gentle reflex, and doing more aggressive recurves as well, mostly using Osage. I always coat with shellac before steaming, but sometimes I will also end up with cracks on seasoned wood (1 year +). Am I steaming too long, and the results being the cracks? Or is it that there is still too much moisture remaining in a 1 year seasoned stave that is causing this with the prolonged steaming?
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You can very easily satisfy your curiosity if you have some scrap osage.....say 1/2 to 3/4 inches thick width doesn't matter as long as they are fairly the same. Steam one for a full 5 minuets, remove from the steam and immediately bend it over your leg or knee etc. Hold for a couple of minuets..... Now do the same with the other piece but leave it in the steam for 35 to 40 minuets......I think that you will find the second one to act like a too dry stick and think you will get some wood damage.
I have bent quite a lot of osage orange with the short time deal and have not had any real issues. I have not bent any of the 90 degree statics because I dont make those bows so cant say as to that but I have bent some fairly sharp tips with good results.
Anyway you can give it a try on some scrap and then you can judge for yourself. You may not like it at all for the type of bows you build.
rich
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Yea, I believe you are correct Rich, I need to go do some experimenting. Thank you
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I have many Amish around me here.Their wheels are pretty nice.Seems a boy coming of age say 18 years or so has to build his own buggy for himself.To go look for a wife most likely......lol.The dad helps though too from what I've seen done.I'll have to inquire from them a bit more once.They are very open about taking about that here anyway.
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Aaron,
I think the biggest difference in using dry heat and steam is what it does to the wood itself. Dry heat will get into the wood and a some point it "plasticizes the resins and proteins etc and there after it hardens the resins (heat tempering a belly) I think of it as turning the inside of the wood into epoxy impregnated cells.....steam on the other hand heats the wood clean through and makes the wood fibers elastic but it does so at the expense of the resins and proteins...a little will make the wood elastic but a lot lets the water in the steam carry away the resins and proteins leaving behind a "hollow shell" so to speak.
I know this view is over simplistic but hopefully conveys the idea behind the thought process.
rich
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With all due respect if your wood is properly seasoned you shouldn't get any checking if steaming for 30 min to an hour and in my experience it doesn't harm the structural integrity of the wood. With a stave thats the best way to get a static bent with no damage
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I may be wrong but is seems like every time someone mentions cracking when steaming they are working Osage. I've oversteamed and understeamed and never had longitudinal checking/cracking but I've never worked Osage. I have had cracking across the grain, but that's been my fault. :-[ :-[ :-[
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I have had well seasoned osage check from steaming 30 minutes plus,,
if i coat the wood,, seems to prevent checking
I have not tried only steaming a few minutes to bend,,
Lauben suggest boiling several hours for a 90 degree bend,, I think as suggested trying some scrap pieces might be in order,,thanks for the info guys :)
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Never had osage to that, 2 hrs seems excessive to me but i have steamed up to 45min to an hr get one ring on the belly and it needs to be thinned down to bend easy. A 5 min steam does nothing in my experiance
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I did a little experiment this morning. I cut a 1 1/2" dia piece of Ocean Spray about a foot long. I rifle drilled it in about 5" so I could put my thermometer inside the wood while I steamed it. I wrapped a bag around it and started steaming. At the start the internal temperature was 70 degrees F. At 5 min. it was 84. At 10 it was 132. At 15 it was 170. At 20 it was 186. At 25 it was 194. At 30 it was 200. At 35 it was 203. At 40 it was 204. The temperature in the bag was a constant 212. Ocean Spray is a very dense wood(I've had a few samples that sink SG about 1) so I imagine it conducts heat faster than a lighter wood, I dunno. I looks like after 30 minutes it's about as hot as it's going to get. I'm watching how fast it cools as we speak. After 15 min it's still 150 degrees. I cut the wood in half to measure the thickness and there is 3/4" of wood all around the thermometer tip. Most bow work would be on thinner wood so the time would be reduced. I may try thinner and lighter wood later.
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Good info DC. Thanks for posting your findings.
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Good info DC. Thanks for posting your findings.
x2
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The wood I had check was in fact osage and I had it in the box for well over an hour, I feel like my wood was dry enough, best I remember about an 8 on my cheap moisture meter. Just a green horn mistake. From what I am reading I need to shorten steam time considerable. No more than 30 minutes? I think the stave is going to be ok but time will tell. Getting ready to start the tiller.
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Arrowbuster...
The idea for me is to hurt the wood as little as possible. You can always re-steam if you don't like the short time method with no harm done. Also remember that I bend by hand and can literally feel the wood bend and yield so if it is too stiff I can stop and reheat without breaking anything. Mechanical bending doesn't tell you about the wood till it either bends or breaks.
rich
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Good info DC. Thanks for posting your findings.
x2
X3 excellent info...thanks
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If you are bending it in hand or in a jig it is still mechanical bending
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In my steam tube I usually steam about 45 minutes for a floor tillered stave, no issues. I always have everything set up so I can move fast once it comes out of the tube, I also keep a heat gun ready in case it take longer that I want. ;)
Pappy
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Did my own little photo-shoot. After seeing DC's post it got my curiosity up so I grabbed a "roughed out bow stave of black locust. It is roughly knocked down in size to 1" thick and barely over 1-3/4" wide, bored the same type of hole and inserted a meat thermometer. The stave had some cambium/ new growth on it (see photos) but no bark and was not cylindrical in section
I did not want the thermometer to be influenced by ambient steam so I got the water to a boil, placed the stave and tinfoil for 4 minuets, then inserted the thermometer for a minuet more for a total of 5 minuets. The gauge read 80 degrees Centigrade (about 185 F) and bent like butter over the wood block .
There are also some close up pics of the bent wood to show there were no lifted slivers, delamination, or crushing.
Here is the pictures.
rich
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close-up pics
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Thanks for that Rich. My next plan was thinner wood and you did it for me. Thinner seems to makes a big difference. It would have heated even faster if you had left it boiling. My piece was too short and fat to bend but I was interested in what temp the wood would bend at. So 185 it bends fine, that's lower than I was thinking. That's good news.
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Good info Rich
Thanks!!
DBar