Primitive Archer
Main Discussion Area => Bows => Topic started by: darinputman on February 11, 2021, 08:34:38 pm
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There has been a bit of talk lately about different forms of heating bows and I have been wanting to try boiling a stave. Why would I even want to try? Well I got a pit for fire hardening and have been looking for a container long enough to put a stave in and boil it before clamping it to my caul thus reflexing and straighening all at once. It seems that wood boiled for recurving limbs bends so easily that It may work out fine. May also be a total waste of time.
Anybody ever tried this. Anbody that has not what are your thoughts also.
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seems like it would work fine,, my only thought is you have to work so fast when bending boiled wood,, Im not sure how that would go,,
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Bradsmith I thought about that, even though about having it clamped to a caul already inducing a few corrections and seeing how that goes. One more question someone may know, if you boil a green osage blank will checking occur?
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Bradsmith I thought about that, even though about having it clamped to a caul already inducing a few corrections and seeing how that goes. One more question someone may know, if you boil a green osage blank will checking occur?
Cannot speak for osage, I know for certain that boiling the ends of a green elm sapling will check badly. That is the only green piece I’ve boiled because I read somewhere, maybe here, that boiling or steam worked well on green wood and dry heat on dry wood. That did not prove true on the piece that I tried and it split wide deep checks where I boiled it.
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Disclaimer that I’ve never boiled a whole stave and have built less than a dozen bows. However, I have boiled limb tips to recurve with mixed success - ok on locust, not on hickory. The locust did tend to check. But that is very different than “heat treating” which is what you mentioned. My concern would be that by heating the entire bow you’re heating the back as well and could be compromising it’s strength in tension. But maybe not. Either way, I doubt this would be considered a “heat treat”.
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Kidder your right I did mention heat treating but I did modify that so as not to confuse anyone else. Thanks, the purpose of boiling would be more for the purpose of reflexing and lining up tips. I personally never worry about the back getting too hot, I do worry about scorching the back but when bending osage I check my wood to see if its hot enough by touching the back if possible and when I can no longer touch it but for a second I consider it ready to bend or make correction. But I have ruint a few staves by scorching the back.
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There is no point in this. Much better to work on one area at a time. It will almost certainly cool too fast.
One thing that boiling is useful for is if you ever get some very difficult to dry expensive wood like say back and white ebony. You can get the m.c. down to reasonable levels by boiling the full piece, 1" thickness = 1 hour. Then remve and wrap in brown paper or similar for the next few % points of m.c., after a month or so you can safely dry the wood.
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I think that it could be a very good point to it especially if a person was to clamp it to a caul before boiling the wood. Boiling caul and all, same way when heating over coals using the fire hardening process, getting heat all the way through the stave without scorching the back. I don't think it would be a problem to make a correction and put back in if necessary. It seems to me that once osage gets hot in water that the wood still bends even though it aint hot as I think it should be. Being able to make several corrections while it is in this state is what I'm after.
Thanks for the comments. I do plan on trying this as soon as I can find a container about 6' long anybody got any suggestions on what to make one out of to try this cheaply, that would also hold up to a fire.
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20 gal drum split in half lengthwise and welded together where the open ends are? Made a bunch of water troughs out of 55 gal drums this way, 20 or 30 gal drums ought to be big enough for what you’re wanting to do though.
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Something like that is about the only thing I can come up with Morgan, it should be able to take the flames for a while. I keep hoping to find some junk that one of my buddys got laying around that will work but don't get out visiting like I use too.
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Piece of rain gutter maybe? But it would not be deep enough for a caul.
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People have put a slanted iron pipe in the ground and then built a fire under it.
Boiling is not good for wood when done too long. I wouldn't use it for wood that needs to be working.
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Thanks aja0, thought about that to test it but may be a little thin.
Patm. I got a block pit set up that I use to fire harden wood just really thinking about something to sit atop it to boil wood in. I never heard that it was bad for wood, but not planning on going to hot. It always seems that when I boil my tips almost as if the wood swells up and softens at the same time. Wood seems to bend while in this state while it really is not even that hot anymore. Kinda amazes me that after applying a little heat it dries right up and seems tougher than before.
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I have steamed an Osage roughed out bow and clamped to a perry reflex type of form as when backing with boo.. had to get bow roughed out for a glue on handle. My set up is a 4" PVC pipe that has a couple of bolts set to keep bow suspended inside pipe glue capped on one end and rubber capped on other. then it has a T set up in middle of pipe that goes to a metal gas can that I fill with water and set over a turkey fryer propane set up.. attached with a fernco rubber sleeve.. it worked like a charm.. boiling a stave is possible but it will take forever and you will need almost a machine type press to bend it...you will need to reduce it down anyway IMO and it will bend much easier and faster which is critical..IMO...gut
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Gut sounds like you got a nice setup there. Sorry my communication skills aint always up to the task. What I'm really considering is boiling bow blanks not staves and I modified the title so as to cut down on any confusion.
When I make a bow I like to get as close to finish dimensions as possible before even starting to tiller. I do so to the point that I come in too light sometimes, but that is kinda the way I like to build. It really helps me in my efforts to keep as much induced reflex as I can and next to a good tiller that is one of my priorities. So clamping down to caul for corrections shouldn't be an issue at all.
I am getting ready to start building out of a tree that yeilded over a dozen good staves so I should be able to take these blanks down really close as they should act similar strengthwise. Thanks
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that set up I mentioned works very well, especially for roughed out full length bows, on my perry reflex design I put deflex in handle areas, that is why I glue on a handle... good luck brother.. look forward to your projects..by the way my osage wasn't green. I've heard and may be corrected is on green wood steam or boil is ok.. on dry wood dry heat is better.. I have boiled and steamed dry wood before with no checking issues.... gut
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You need to know or find a plumber , pipe fitter that probably has scrap pipe. Tell him your need . If he smiles it will probably be made for you. That’s how I would get one. 6” iron pipe with end caps 6’ long cut in half will yield two boiling pots. Arvin
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That is a good idea Arvin.
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If you are going to pre-clamp it to your caul, 6” pipe may not be big enough to allow for the caul and clamps. If cut in half will only give you3” at deepest part. Then you have to worry about how much evaporation you would have during the process.
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As far as damaging wood by heating it; I worked in a coal fired power plant, the building heat manifold outside my office had a steam supply of 600LB pressure and no telling how hot, 1000 degrees perhaps.
On midnight shift when no one was around I would take my full length bending caul and steam tube into work with me. I would run a line off the drain on the manifold into my steam tube and let her rip.
I steam straightened a number of osage staves with this method, never had any checking or damage to the staves. I would give them a steam bath of about 30 minutes before I clamped them to the caul. Of course I wasn't using 1000 degree steam by the time it traveled the length of my steam tube but it far hotter than boiling water, it was invisible steam at the temperature it was at, no water vapor.
I made some fine bows from those staves, this was 25 years ago, I bet all the bows I made from these superheated staves are still shooting.
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Yeah bentstick you got a good point.
Eric the staves still have a little moisture to drop before I start on them so maybe I will have what I need to boil them in by then.
I had hope that someone here had tried boiling a blank but it looks like I'll be going it just based on what I learned from bending tips. I look forward to trying something new.
Never know may have to come out with a boiling osage for selfbow dvd. Relax fellows just kidding.
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I think that it could be a very good point to it especially if a person was to clamp it to a caul before boiling the wood. Boiling caul and all, same way when heating over coals using the fire hardening process, getting heat all the way through the stave without scorching the back. I don't think it would be a problem to make a correction and put back in if necessary. It seems to me that once osage gets hot in water that the wood still bends even though it aint hot as I think it should be. Being able to make several corrections while it is in this state is what I'm after.
Thanks for the comments. I do plan on trying this as soon as I can find a container about 6' long anybody got any suggestions on what to make one out of to try this cheaply, that would also hold up to a fire.
What sort of form are you going to make that withstand being boiled!!!!
You can do everything you say by using a normal form and a heat gun :) Much easier and will give better results. I certainly wouldn't be boiling a full stave, also that is some fire you are going to have to make to boil all that water.....I know how much heat/energy it needs to boil a pan with hornbow cores in....honestly I wouldn't waste my time with all this - no advantage and lots of extra work :)
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Bownarra, I get it you think its a waste of time. I do appreciate your comments. But with that being said I don't know if there will be any advantages or not. I am yet to hear from anyone thats tried it. Also I plan on boiling bow blanks, sorry I stated staves at first but modified title to read blanks.
I don't know how high of a boil you have to bring your blanks to to for bending curves, but its not a roaring boil for me. This winter I was working on a blank, came time to put curves in it and thought I'd try out the kerosene heater for my heatsource. I put about a 11/2 gallon pot of water on the heater and thought it probably will never get to boiling. It never acheived much over what I'd call a simmer, but after about 45 minutes of simmering osage it bent fine. Reapeated the same on the other tip.
I get it you think it's a waste of time, your opinion is noted thanks. But if I can ever come up with a pot like I want I will give it a try. I have wasted more time and wood in this bow building than I care to admit. Tried to do some silly things to wood some worked some didn't. But thats ok, its what I like to do.
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Bownarra, I get it you think its a waste of time. I do appreciate your comments. But with that being said I don't know if there will be any advantages or not. I am yet to hear from anyone thats tried it. Also I plan on boiling bow blanks, sorry I stated staves at first but modified title to read blanks.
I don't know how high of a boil you have to bring your blanks to to for bending curves, but its not a roaring boil for me. This winter I was working on a blank, came time to put curves in it and thought I'd try out the kerosene heater for my heatsource. I put about a 11/2 gallon pot of water on the heater and thought it probably will never get to boiling. It never acheived much over what I'd call a simmer, but after about 45 minutes of simmering osage it bent fine. Reapeated the same on the other tip.
I get it you think it's a waste of time, your opinion is noted thanks. But if I can ever come up with a pot like I want I will give it a try. I have wasted more time and wood in this bow building than I care to admit. Tried to do some silly things to wood some worked some didn't. But thats ok, its what I like to do.
Yes I agree with Bowanarro some what but all that s been learned and shared here came from like experiments. I’m interested cause I know that plumber guy. My interest is how dry bow blanks will respond to the boil. I would probably try and make one for one limb at a time though, hooking the tip at one end and bending in place on the caul as fast as I could An clamping.
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Arvin, that may work as well.
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I am an experimenter as well, takes the hum-drum out of bow making and you never know what you will find or learn. Always a lot of nay sayers around to try to get you to conform to their way of thinking but I have never been a crowd follower, neither is Darren
Darrin and I live in the land of osage so if a piece or two ends up as firewood it's no big deal, I have turned a good bit of osage into firewood along the way.
Darrin is much more experimental than I was and I love watching his projects develop, nothing ventured nothing gained in my opinion.
Case in point; my tillering gizmo was the result of a bunch of different ideas, fumbling and design changes to end up what it is today, a good bit of experimenting, so there.
The first gizmo, pretty rough, the screws held the pencil;
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I got tired of heat treating one limb at a time. So I made the jig to do both limbs at once. This was simple enough because I am using silicon heating strips. It works fine if the limbs do not have much curves. But even for a simple recurve, it is a hassle to make sure both sides match each other rather well.
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Would love to see a picture of your heat treating set-up.
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I got tired of heat treating one limb at a time. So I made the jig to do both limbs at once. This was simple enough because I am using silicon heating strips. It works fine if the limbs do not have much curves. But even for a simple recurve, it is a hassle to make sure both sides match each other rather well.
That’s s one reason dry heat is so nice . If it takes three trips to get that recurve bent so be it.
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Eric thanks, one of the things I like about the gizmo is that it will teach proper tiller if used correctly. I know it has helped me out tremendously.
scp sounds like it could be very beneficial. I would like to see it as well.
Arvin I use a lot of dry heat and never thought of doing it any other way untill I messed up a few recurves. I guess I just had more trouble than most bending recurves, for me boiling was the cure. Still use dry heat to correct them, but have settled on boiling for initial bend, for now anyway.
I guess thats what I like these forums so much, lots of different ideas, some work some don't for me anyway. But I will never believe that just because someone says it will not work they are right it may not work for them. But someone else may make one slight change that will change the outcome, whether they do it on purpose or by accident. I guess I'm just hardheaded that way. Thanks to everyone for all the comments and maybe one day I'll be able to update thread with some results. Until then I will just continue to enjoy the learning process.
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Would love to see a picture of your heat treating set-up.
Sorry, I don't takes pictures other than for photo IDs or insurance purposes. I might change that practice if I ever actually do any real worthy experiments in bow making.
It's just a 2x4 with some small curved blocks screwed on top. The bow is clamped on top of blocks, belly side up. Then I put on top the silicon heating strip, a thin silicon pad mat, than a heat pad neck wrap to weigh everything down a little. I also use the built-in thermostat of the heating strip and a push button digital timer with auto shut-off. I usually turn the heat on at 170°C for 20 or 30 minutes.