Primitive Archer
Main Discussion Area => Bows => Topic started by: Carson (CMB) on February 12, 2013, 09:18:13 pm
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Forgewood was the trade name that Bill Sweetland gave to his compressed Port Orford cedar shafts. I won't go into the awesome details of Bill's process for making the forgewood arrow, but basically he took a top-tier arrow wood and made it even better by manipulating it with steam heat and hydraulic pressure. I had a thought that maybe this approach could be applied to bow-wood much in the way heat-treating is utilized. Can heat and pressure, make good bow wood better? Can it make marginal bow-wood into excellent bow wood? I just want to throw this vague question about compression treating wood in order to change its properties out there to hear others thoughts on possibilities, potentialities, practicalities, and other p words about compressed bow wood. ;D ;D
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Carson I have some of the sweetland compressed cedars and they are incredible. Sweetlands shop forman (Bill) Told me that for demos they used to cut the shafts into 2' pieces and drive them into a plywood board for the shows.
I have some that has regained a little moisture over the years and swelled back to original shape. Amzing to this a half inch bolt can get compressed to about a 1/4 shaft.
I think the general idea is plausable and whorthy of trying. Similar to boning the back of a bow
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Very curious Carson.
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The pressure is the trick. Its easy to come up with pressure for something like a shaft. But a stave or blank is another story......hhhhmmmm.....dang-it! Now Im gonna scheme half the night and wont sleep.
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I'm with yah there pearly now I'm gonna be up all night thinking about this!
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I think you volunteered yourself, Carson. ;)
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Keenan, if I remember right, your stash of Sweetland shafts was quite the score. There is a video out there that documents the process and how Sweetland came up with the idea. It is fascinating, and his shop is unbelievable. I heard he held patents for the modern oil filter. :o
Pearl, it would definitely be easier to apply to laminations than staves, but there might be some crude methods that allow even pressure to be applied on wood that is not neat and flat in dimensions.
This going to occupy my mind when I should be thinking of a valentine's day gift for the wife :-*...I am doomed :-\.
Weylin...you might be right. As slow as I go though, it might be awhile before we learn anything. Hopefully Pearl takes off on this and we have some real world results by the end of the night ;)
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good to bring this up. I have several of sweetlands arrows and love to shoot them. the process he used was very labor intensive and there were some chemicals involved which couldnt be used today. the compressing of the fibers to the extent he did made the shaft extremely dense and made the shaft a lot stiffer. I have some sweetlands that are over 90# spine and are only 5/16" diameter. as far as making it into a bow wood I dont know. I know that these shafts do seem more brittle when you bend them too far. I also dont think there are many woods that could be condensed as far as the cedar, because of the softness and the large growth rings. I think it could work but would need to be backed with a more tension tolerable wood. give it a try and let us know the results :) I also think bill did build some bows, dave doran at archery past has a oregon archery museum display box with his arrows and bows in them. he would know for sure if he made them.
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Just build Lauren a giant stave pressurizing contraption in the living room for valentine's day. I'm sure she'll swoon for that!
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Brilliant, it is like you know her better than I do. ;)
Dave, I guess I wasn't thinking of limiting the application to POC. Just what or how could you compression treat bow wood in stave form or laminated, and what woods would benefit, or be most suited to it.
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A press would not be that hard to do. I built and designed all types of machinery for about 45 years. I think it could be done fairly easy, even with character bows. Think of how a constrictor (Python) works. Just as a form works for a laminated bow The thoery would be similar. Since pressure equalizes inside the tube, the pressure would be fairly consistant except for slight variance of the limps or nodes of character bows.
The press would need to be consistant with the stave so if it matched the caul form you could heat treat and then go to the pressure form and another heat session. Now if we can just incorporate the weather enhanced aging station we could whip out perfectly seasoned,and condensed stave for the world of super bows Sorry for the ramblings of the mind.
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What about using those set ups they use to veneer at home with the suction pump and basically one of those space saver bags that are on TV commercials? I dont know how much psi they produce or how much is need to do what you are thinking but I thought I would throw that idea into the ring.
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For enough force ood say it will require hydrolic and not air. Another option would be to use hard rubbered presure rolls on automatic pressure shocks to conform as it rolled over the wood. The trick would certainly be how to not breaks the firber strands in the process
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we are talking several tons of pressure as well as steam. Keenan, if you can go to dorans and get the video he outlines his process. he also used Penta and other chemicals. you would have to do it with board type wood so as to get the consistancy. he used tapered boards to achieve the tapered shaft. Carson, I doubt you could get Osage for example to compress much beyond its current state, also with osage you have different wood structures within the wood, early wood and late wood. to oprimize the compression you would need soft wood, IMO. but then again, what do I know, I am just a crazy bowyer....but I am in good company here ;D good subject, this should keep Keenan awake for a few days :D
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Next thing you know you guys will try to figure out how to put wheels on Bows ;D >:D ;D :-X :-\ sorry about that
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Next thing you know you guys will try to figure out how to put wheels on Bows ;D >:D ;D :-X :-\ sorry about that
Soy, shame, shame, shame, Did you realy speak such an evil? LOL :o
yes Dave I'm sure your right I may not sleep tonight as well. Thanks guys. Make it Stop!! :o ::)
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Soy ya took the words right out of my mouth:)
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Tons of research has been done on the subject. Densified wood is what they call it. Being an engineering student I looked into it a bit. Here is what I found from looking at scientific articles:
- Needs heat but not too much. Too much will collapse the wood cell walls and the product will be brittle. Different studies recommend different temps though. 280 F is listed often.
- A compression ratio around 50-60% seems optimal ( ie 1'' being compressed down to 0.5 or 0.4'')
- Need pressure. Lots of pressure. For normal wood compression strength is about 500 to 1200 psi. Should be less for heated wood but still, take a stave 1'' wide * 60'' long = 60 sq. inches.
It would take 30 000 pounds to compress that piece of wood (60*500). 15 tons is a big press. And it's gonna be twice that if the stave is 2'' wide.
But the results are good. Better hardness, higher modulus of elasticity. not too brittle if it's done right. it seems wood properties are pretty dependent on density (same thing mr. Gardner found out with the mass principle).
Anyway there is info available on the wood densification process, just maybe not on standard Google. I have access to academic study journals through school, that's how I found out. Maybe Google scholar will have more results. Good research!
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Welcome to p a bringer of knowledge ;) hope to hear more from you in the future!
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Hardly a project that can be labeled "primitive";-)
Interesting though, from a technical pov.
Cheers
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Hardly a project that can be labeled "primitive";-)
Cheers
Holten, who says I wasn't going to use a really, really big rock and some log levers? ;D
Albert, that information is gold. Welcome bringer of knowledge!
Dave, I agree it would need to be a softer wood. Douglas fir keeps coming to mind. I am looking for a way to take an abundant wood and make it bow forgewood.
Keenan, I was thinking of a giant water weenie to apply hydraulic pressure to odd-shaped stave wood. Just have to make sure that thing doesn't shoot that stave out through the wall when it reaches those kinds of pressures! :o :o
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Cool concept...but im thinking the pros of a compressed wood bow will come with some not too small cons.
The weight will be doubled at same measurements,and even if you thin it to ridiculus thin the tips will still be heavier than prefered.
But i can totally see the advantage of using it in lams.
I also get this silly picture in my head of a rainy day out with your comperssed bow where it pops like a popcorn to original size :o :o ;D
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Aren't the edges of older wooden cross country skis usually made of some compressed beech wood? I googled it and found out they still make some, it's called lignostone. It's a kind of beech plywood compressed to about 1.4 SG.
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Carson, one word...CHOCOLATE!!! ;) Relatively cheap, readily available and generally a winner. 8)
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My father in law is in the hardwood lumber business and he has mentioned a process that sound similar, but they were using it as he described it "tie oak in knots". Building the press would not be to hard just a matter of time and money.
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In one article about Bill it said Chester Stevenson used the process in bow-making:
"A little known facet of his business was compressing wood for use in bow making and several bowyers were the beneficiary, the most name worthy among them being one Chester Stevenson from Eugene, Oregon. Chester made several laminated bows utilizing both compressed yew and lemonwood. Bill's process could effectively reduce the lamination to 60% or so of its initial thickness, changing a given wood's density, color, hardness and size without any loss of its original characteristics"
See: http://www.stickbow.com/FEATURES/HISTORY/sweetland.CFM
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I've got some relevant experience for this one. I'm currently wrapping up my senior design project at UNB where I am a mechanical engineering student. We built a hydraulic press to compress biomass up to 200MPa, or just under 30,000psi to make briquettes. Its working great and we are doing full testing later today.
According to what Albert reports, you'd need a pressure of around 1200psi to cover all woods. Then its probably best to have a maximum available pressure of 1500 so that you have some wiggle room. The way I see it, the easiest way to compress the stave evenly would be to have the stave within the pressure vessel with the fluid so that the fluid does the work of compression.
So you would need to custom build a pressure vessel with a removable, resealable lid, and the proper connectors for a hydraulic pump. Now you can get a hydraulic pump that can supply up to 3000psi for under $500 bucks. Hook that up to your pressure vessel in conjunction with a check valve so that once you reach your desired pressures you can hold them, and also a pressure gauge so that you can monitor how much pressure you are applying. Make sure your lid is sealed and bolted down, then run your pump up to the desired pressure. Let the stave sit for a while then release the pressure and remove the newly compressed stave/bow.
The only issue with this is that your bow will likely be saturated with whatever you are using for a fluid. But I'm sure you could rig up a system to run with water as the working fluid.
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I read this whole post... Man this all sounds way to complicated.
It is way out there for Primitive Archery. But there is no harm in thinking about it.
It would seem to me that Osage would delaminate if it were compressed to the extent that you guys are talking. The early wood could not stand it.
Here is something I have thought about for some time.
Find a super prime Osage stave from a large diameter tree.
Cut out the late wood rings with a bandsaw. Plane then so that all the early wood is gone and they are perfectly flat. Now make your strips and glue up your bow.
It would most likely need some sort of backing.
It is possible that someone has already done this and I just don't know it...
David
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There was a guy who made a lignostone bow and it didn't perform any better than a typical bow. I don't really see the point of overly densifying wood. We already know that bows with wildly different sg numbers can come out the same in performance.
If anything finding ways to reduce mass and preserve strength is a better scenario. Making a bow wood totally solid will make it like a solid glass ,horn or metal bow, none of which is going to light up the chrono.
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We built a hydraulic press to compress biomass up to 200MPa, or just under 30,000psi to make briquettes. Its working great and we are doing full testing later today.
I'm doing my best not to imagine living in a house built of biomass bricks! :o
The 3 little pigs didn't make it to that one!
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There was a guy who made a lignostone bow and it didn't perform any better than a typical bow. I don't really see the point of overly densifying wood. We already know that bows with wildly different sg numbers can come out the same in performance.
If anything finding ways to reduce mass and preserve strength is a better scenario. Making a bow wood totally solid will make it like a solid glass ,horn or metal bow, none of which is going to light up the chrono.
Exactly right.
I got a board of lignum vitae (the tree of life) which is the densest wood in the world. I've made a quite a few different styles of bow from it , varying width/thickness ratios, different cross sections and everything else I could think of........ and have to conclude that even though it's denisity of 1.3 s.g. can't be touched it ain't all that as far as bows go.
I think the key to a fast bow is getting an ELASTIC piece of wood and tillering it perfectly............simple ;)
Density by itself is overated, bows need other properties from the wood.
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David, you are right that Valentine's day thing is way too complicated! ;) Actually, I hit a home run. I booked a little ocean fishing trip, and she loved it. The trip isn't for another couple weeks...hopefully we bring back plenty of fillets, bow-backing skins, and fish glue! ;D
David, What about doing that with osage staves that have lots of early wood. When I think of super prime osage, I think of next to no early wood.
Slackbunny, you make it sound so easy. I doubt I will be setting it up anytime soon though. I was thinking of a pressurized canister for impregnating arrow shafts with different drying liquids. Kind of like Bob Lee's DuraWood risers. That would not have to have near as much pressure, or maybe that should use negative pressure? Anyway, that might be a good build to get me thinking what a stave compressor build would go.
Berny, I had never seen that bit about the compressed bow wood lams by Bill. Makes sense that he would have applied his technique to bow woods. Also, makes sense that it was applied to laminations rather than staves. I wonder what Chet thought of the compressed bow lams. Would be cool to see one of those bows.
Dauntless, that lignostone sounds interesting. But I see now with some more recent replies here that it has been tried and the results not that exciting.
PatM, Mike, I am thinking more along the lines of taking a softwood and making it dense, rather than taking a dense wood and making it extremely dense. I would like to find a way to make use of locally abundant woods in making production bows. Like ash-backed compressed cedar or fir. Just a thought.
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Just my opinion, but I really think if you compressed the wood that much, it would be more likely to snap and loose it's elasticity. By the way isn't burnishing a primitive compression technique? :) Laminate bows with glass protection would be a seperate issue in my mind, there may be gains in that area. Interesting conversation none the less.
VMB
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Slackbunny, you make it sound so easy. I doubt I will be setting it up anytime soon though. I was thinking of a pressurized canister for impregnating arrow shafts with different drying liquids. Kind of like Bob Lee's DuraWood risers. That would not have to have near as much pressure, or maybe that should use negative pressure? Anyway, that might be a good build to get me thinking what a stave compressor build would go.
Yeah it sounds easy. Its a simple concept but I can pretty much guarantee that the build would be a nightmare, unless maybe you're a machinist. The average joe does not have the expertise or equipment to whip out something like that. The removable, resealable cap on the pressure vessel would be quite troublesome I imagine.
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Now if only we could incorporate liquid metabolic residue from large bovine North American ungulates into the process.... >:D (Sorry mullet, I could not resist)
As I was reading this I kinda went the direction that soy did. And where do we draw the line that seperates primitive archery from traditional archery and modern archery? Yup, pretty interesting to talk about, even scheme over while drinking a yeast enhanced grain extracted fluid compound. But is it something I would want to do? Not so much.
Thanks for the discussion, though. It's one of the things that makes this forum so rich and entertaining. That and the amazingly broad range of disciplines we all come from to be here.
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Compress it with water and then wait another 5 years for it to dry out and season or maybe take green wood and just squeeze the water out of it like a dish rag. WAY over my head. The way I see it you should compress it with tru oil and make in impervious finish.
I'm a prime example of the "keep silent and people may thing you are ignorant. Open your mouth and you'll leave no doubt."
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some interesting work has been done in fabricating snowboards using vacuum presses, suck the air out and let the atmosphere do the work and presses made from inflated fire hose confined in a big press made from I beams
http://www.skibuilders.com/phpBB2/viewtopic.php?t=485
or fabric
http://skibuilders.com/phpBB2/viewtopic.php?t=1820
just something to think about.
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Maybe I can get a "snowboardyer" to let me use his press. I could see if the process has any merit before getting too vested in it.
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PatM, Mike, I am thinking more along the lines of taking a softwood and making it dense, rather than taking a dense wood and making it extremely dense. I would like to find a way to make use of locally abundant woods in making production bows. Like ash-backed compressed cedar or fir. Just a thought.
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The problem with these woods is the distinct difference between the early and late wood. The point I was making is that density is far from everything when it comes to making bows!
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Mike, I completely agree that density is not everything for bows. And like you said in the earlier post, it is about elasticity.
And Albert reported on page 2 here that there is increased modulus of elasticity from the compression process. That is encouraging.
Fir's distinct difference in early/latewood might be tricky. POC is less distinct and maybe that is one of the reasons Sweetland chose it for his compressed arrows.
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Years ago I had gotten pretty far into working out a purchase of Mr. Sweetland's machinery. My plan was to make Forgewoods and sell them commercially. I thought it was interesting that POC is called Chamaecyparis Lawsoniana or Lawson Cypress, being as my last name is Lawson.... ??? Talking with the Forest Service I found that to acquire enough "arrow grade" POC was just not doable today. So I backed away from it.
When you are talking about this process the key component is POC and it's properties. This wood has enough of a naturally occurring substance that when brought up to 220 deg. under pressure solidifies into a glue. No other wood has enough of this substance to do this effectively as does POC. This is why with all the experimented that Mr. Sweetland did he used POC. I know the current owner of the machinery tried hemlock and other woods not as successfully.
So, I would think that if you were to try this with osage or some other wood you would have to inject it with a substance that would allow all the wood fibers to compress and then bind permanently. The mass weight of a bow made from this would be extremely heavy too...?
The picture is of Mr. Sweetland's platen press.
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Very interesting Snag.
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So the real reason nobody is making forgewood shafts is that there is not enough POC? Ok, someone needs to plant a few thousand acres of POC, tend it carefully for a couple hundred years and go into production!
And folks wonder why conservationists want to set aside old growth forests?
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I was told by the FS person who handles the bids on timber that there is only 200 acres of standing POC that will make quality arrows. Now take into account that that isn't 200 acres of solid POC. That just means that on that 200 acres there is "some" POC.
This is on public lands. The Coquille Native American lands hold some POC but I was told they are definitely not cutting any of it. I spoke with the man who manages their cranberry business.