Primitive Archer
Main Discussion Area => Bows => Topic started by: Eric Krewson on March 22, 2018, 11:11:06 am
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A lot of guys just starting out ask how to treat osage once they cut it. I thought I would give an example on what not to do which is take the bark off and leave the sapwood. Even well sealed the sapwood will often check, in this case 4 coats of shellac didn't keep this osage sapwood from checking. When sapwood checks it often caries the check deeply into the heartwood. There are 5 checks on this piece of osage the went into the heartwood
(https://i.imgur.com/6ZlzQVA.jpg)
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And, once a check opens, its edges are not sealed and drying and shrinking occur rapidly with almost all the moisture loss in the crack.
The sapwood is harder to seal, because it has much more moisture in it than does the heart wood.
I have found though, that if the wood is split into stave size, there is much less tendency to check.
Good useful post Eric
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Yup, I gotta say this is some pretty useful advice! In the bad old days, I used to get staves from a dealer with bark and sapwood still on. More than once the wood was checked so deeply that it was chucked out. Kinda hurts to see a hundred bucks wasted like that!
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I have to counter this with what I have observed. If you split a stave into individual bow sizes, the ability for a stave to check is almost nil. The narrower a stave is, the less it can split. As it dries and shrinks, it uses its own width as leverage to split. Reduce width, recuce leverage, reduce checks. I never remove sapwood anymore and have learned this.
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I will counter what you countered with, Kevin. I split up four big logs into bow size staves and ruined every one with checks, all of them. That's the only batch I've ruined and it wont happen again.
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JW_Halverson: In the bad old days, I used to get staves from a dealer with bark and sapwood still on. More than once the wood was checked so deeply that it was chucked out.
REALLY? Bark on, even. That amazes me.
That is a nice big piece of wood, too, Eric, and a good lesson.
I don't harvest my own osage, but years ago I did cut down a 14" diameter black locust, in Utah, in August, at just after noon; 98 degrees, 25% humidity, and a slight breeze. I was on a tree job and didn't know better then, so I split it six ways or something, took the bark off, and set it aside to take home.
I came back literally less than an hour later and the sapwood was checking all over the place. I saved it, but I had to hose it down, cover it in the shade with a tarp, and periodically come back and hose it some more.
If it had been a white wood, those were already big enough checks to have completely ruined it.
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I will counter what you countered with, Kevin. I split up four big logs into bow size staves and ruined every one with checks, all of them. That's the only batch I've ruined and it wont happen again.
I wonder why there is a difference?
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I think some difference could be when the tree is cut. I’ve cut Osage in summer when it is hot out and had water running out the ends before it was on the ground.
I’ve cut some in winter and had several days to work with before I could get it sealed.
There is less moisture in the tree in the winter, plus the cooler weather lets it leave the tree slower.
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There will be exceptions depending on where you live. I still cringe when I think of this; after I cut the most perfect osage tree on the planet I split it down into staves, stripped the bark off and put it in an outside garage that was closed up, I had shellacked the staves backs. A month later I looked at the staves and could have dropped a dime out of sight into the checks that went from back to belly.
This was around 20 years ago, I bought Deans book "Hunting the Osage Bow", followed his osage cutting advice and never lost another stave until I got lazy. About 10 years ago I cut the osage in the picture above, shellacked it and put in the somewhat damp crawlspace under my house, it still checked, lesson learned.
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That is quite a wide quarter split, such a piece begs to crack in drying, even when sealed. You can still probably get 3 useable English longbow staves, or 1 longbow and a very wide flatbow out of it. You would need to glue and clamp that shallow split though.
I have found it necessary to take the sapwood off osage cut in summer. Not just because it attracts bugs or splits, but it can go moldy, or the sugars start to ferment. I'm not sure which it is, but it goes greyish and gives off a vinegary smell. I haven't found it
to stop you from making a bow out of it, just cosmetic, like a bluestain in other sappy timbers like ash.
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Osage doesn't play by a strict set of rules. I've had them check like Eric's. I've also had them check really bad with the bark left on them. I've had some that I didn't seal at all and they never checked. I think the type of grain plays a part in it. If it's straight grained and easily splits into staves I think it has a greater chance to check if not sealed properly. I have some osage that almost refuses to be split. I tried busting some 6" long pieces with a hatchet yesterday for firewood. It wouldn't budge. Even when hit really hard with a hatchet. I gave up and threw it in the campfire pile. I broke my started wedge trying to split that same stuff into staves. I've noticed that if you run into a problem with one stave, the rest from that tree will likely be the same way. I cut one tree that was very dark red and super hard wood. Every single stave developed side checks. The ends and backs were fine.
From my experience, the absolute best way to treat osage is to cut it this time of year, seal the ends, split it into chunks as soon as you can so the moisture has a place to escape besides the ends, split the chunks down into staves, remove the bark and sapwood, seal the backs and ends at least 2 times, store them in a place that doesn't get too hot or direct sunlight. This will reduce the possibility of checks and bug damage. They also take up less room and are cleaner to store and move around.
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I like to seal with a thick sloppy coat of latex. I use what I have or can get cheap. Don't pass up an old partial can of latex at a yard sale.
I also make sure to get the staves out of the sun and wind. I usually leave the bark on and spray with malthion or Sevin.
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OO has had more experience with Osage than anyone I know and if anyone has deal with more osage than him I'd like to know.
I have and would go with his advice on osage cutting and stave seasoning....
DBar
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I'm one to always make staves immediately/seal the ends[I like shellack]/ pull the bark and sapwood off/chase a ring/seal the back[I like shellack]/then hopefully during a period of mild cool weather[60 degrees or less] for a few weeks or more inside a shed/then I have little worries the stave will check then with up coming hotter weather.In short in the beginning cooler weather to slowly release the moisture which coincides with harvesting them in the fall or winter or early spring the best time that I like.I've had bad luck with cracks myself leaving the sapwood on to dry.
I do like the looks of a sapwood backed osage though done by others.
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d, I like your approach....and I do like the looks of a sapwood backed osage bow .... but the "stave" has to tell you what type of bow "it" wants to be..... and I'm sure you understand what I'm saying......but if I'm looking for a bow with a sapwood back I will take it down to about a 1/4" of sapwood when green and bring the belly to bow dimensions.....seal the ends and back real well with shellack or polly and put it indoors for about a year. Don't seal the belly it will give the moisture a place to escape.....
DBar
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A lot of it comes down to wood physiology.
Heartwood is dead, and has had time to dry out slowly. Sapwood is saturated with water, and will therefore shrink much more and more rapidly than heart wood. This difference in shrinkage speed causes cracks. Sealing reduces this differential.
This is also why bole planks become concave on the outer side: the outside of the trunk contains more moisture than the inside, hence it shrinks more.
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Just curious has anyone tried curing Osage in water? I've seen it on YouTube. It's supposed to replace sap with water I think. Maybe it would dry more even then when removed from water? I really don't know just curious if anyone has tried it.
Bjrogg
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BJ.I've heard of that too.Heard it would take the sap out faster under deeper water under more pressure.I've never googled it but I'm sure there's some info about it.Also heard the old timers used that process when their wagon axle or spindle would break down on the trail west settling America and would quick dry a replacement part.Also heard with dry ice dried it faster too.
I'll still just cut enough and let it air dry naturally.
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Thanks Ed I was just wondering if it might keep checking in check. I saw it in a bow make my video.
Bjrogg
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No Osage or Locust grow here but I have cut a few whitewood species in late Spring/early Summer that checked with the bark on and bark off and sealed. I suspect that timing plays a role in back checks. If the sapwood has too much water in it when the tree is cut, such as in late Spring when the tree is starting to bud, then it is more likely to check.
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I've never done it but steaming the whole bow helps dry or drive the sap out too I've heard.Though not sure about the checking deal afterwards.
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I will counter what you countered with, Kevin. I split up four big logs into bow size staves and ruined every one with checks, all of them. That's the only batch I've ruined and it wont happen again.
I wonder why there is a difference?
Heck I have no idea man. Climate maybe?
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In Alabama you can cut osage in the dead of winter and sap will run out of the log after you cut it.
I wonder if water curing was a primitive way to keep the bugs at bay until the stave could be worked. It looks to me that you still have to dry it after it comes out of the water.
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I don't harvest any osage myself and am dependent on several suppliers I use. It sounds like when to cut is very important. Most of the wood I receive with bark still on is usually less than 3 months cut and still pretty wet but past the high risk point of checking. I have had good luck starting at this point just taking them all the way down to roughed out bows. As long as I use a sealer on the back I seem to be ok. If I don't I stand a good chance of getting some minor checking in the limbs. I normally seal with tightbond glue or sometimes latex paint or even toilet bowl wax.
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In Alabama you can cut osage in the dead of winter and sap will run out of the log after you cut it.
I wonder if water curing was a primitive way to keep the bugs at bay until the stave could be worked. It looks to me that you still have to dry it after it comes out of the water.
Yes but water leaves the wood faster than sap moisture it seems after steaming or pressured water drying.
I doubt if the ground freezes very deep in Alabama.Up here it freezes up to 5' deep at times.Osage cut here in the dead of winter will not have sap running out.At least I've never seen it.
I've read the bugs will leave the wood alone after it gets below 20% moisture.Think Tim Baker stated that.
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In Alabama you can cut osage in the dead of winter and sap will run out of the log after you cut it.
I wonder if water curing was a primitive way to keep the bugs at bay until the stave could be worked. It looks to me that you still have to dry it after it comes out of the water.
Yes but water leaves the wood faster than sap moisture it seems after steaming or pressured water drying.
I doubt if the ground freezes very deep in Alabama.Up here it freezes up to 5' deep at times.Osage cut here in the dead of winter will not have sap running out.At least I've never seen it.
I've read the bugs will leave the wood alone after it gets below 20% moisture.Think Tim Baker stated that.
Ed, I think you are safe from bacteria and fungus below 20% but bugs will attack anytime if the bark is left on and as said above if you remove the bark and not the sapwood you are prone to more checking.
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Wood cured in water has interesting properties:
first, it removes the edible parts for bugs and fungi, as sugars and other yummy compounds are slowly extracted (like from a tea bag). So water-cured logs are much more resistant to decay. Since the wood structure is more porous after curing, the wood dries faster once sawn.
Second, it saturates the entire log with water, also the heart wood, which was drier than the sapwood. Slabs, boards and planks sawn from water-cured logs are dimensionally much more stable, have less warping and checking during drying, because there isn't any difference in moisture content across the wood.
Unfortunately, water-curing logs takes at least a year, preferentially even 2-3 years.
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Pressure water soaking goes faster than osmosis type soaking.Something setting under 20' of water is subjected to much more pressure than at 2'.
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Wood cured in water has interesting properties:
first, it removes the edible parts for bugs and fungi, as sugars and other yummy compounds are slowly extracted (like from a tea bag). So water-cured logs are much more resistant to decay. Since the wood structure is more porous after curing, the wood dries faster once sawn.
Second, it saturates the entire log with water, also the heart wood, which was drier than the sapwood. Slabs, boards and planks sawn from water-cured logs are dimensionally much more stable, have less warping and checking during drying, because there isn't any difference in moisture content across the wood.
Unfortunately, water-curing logs takes at least a year, preferentially even 2-3 years.
I was thinking like these statements. It does seem to me like if you got rid of the sap you'd get rid of the sugars and maybe the bugs.
That's also why I thought replacing sap with water and evenly hydrating the entire stave may even though drying faster dry more even and help prevent checking. The video I saw they just put stave in a creek or pond was only a foot or to deep. I'm sure like Ed said deeper would be faster.
Bjrogg
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I just calculated it and @ 20' depth pressure is 23.5#'s per sq. inch.10' depth 19.1#'s per sq. inch.
Pressure or freeze type drying I think is definitely faster.
Water leaves wood a lot faster afterwards for drying than sap but like you said I'm not sure what that does to those resins and sugars in wood.
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Do you really want to rinse those sugars and what all out? I would think that leaving them in(air dry) might increase the compression resistance.
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For bow making purposes I would'nt care to do it.Although sugars and resins should not be able to evaporate like moisture but might be lost from the pressure.
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"I've read the bugs will leave the wood alone after it gets below 20% moisture.Think Tim Baker stated that." I think that's true of fungi, but I've had staves sit for years in my dry garage, waiting to get to them. Some were fine for 3-4 years, then suddenly the powder post beetles got em.
I have also noticed, at least with elm, yellow locust sapwood, and some plum, that the bugs FLOCKED to it after I had heat straightened it and left it sitting longer than I intended. Cooking seemed to make it sweeter.
BowEd has mentioned, but remember that sap is different from water, and green wood has both.
Then, to stir the pot, I remember reading MANY years ago in the "on the rack" Primitive Archer magazine about SALT WATER curing of bow wood. Anybody do that, or remember how it goes.
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The old time bowyers from the late 19thC and early 20thC thought freshwater cured wood was inferior to air dried wood for bowstaves.
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Just curious has anyone tried curing Osage in water? I've seen it on YouTube. It's supposed to replace sap with water I think. Maybe it would dry more even then when removed from water? I really don't know just curious if anyone has tried it.
Bjrogg
I have done this, I don't believe you are replacing sap. What I think is happening is you are satuarating the wood with a equal MC which in turn leads to a more even drying since the wood should dry at a consistent rate. Sapwood near the cambian is much wetter than the interior wood is my belief.
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Wood cured in water has interesting properties:
first, it removes the edible parts for bugs and fungi, as sugars and other yummy compounds are slowly extracted (like from a tea bag). So water-cured logs are much more resistant to decay. Since the wood structure is more porous after curing, the wood dries faster once sawn.
Second, it saturates the entire log with water, also the heart wood, which was drier than the sapwood. Slabs, boards and planks sawn from water-cured logs are dimensionally much more stable, have less warping and checking during drying, because there isn't any difference in moisture content across the wood.
Unfortunately, water-curing logs takes at least a year, preferentially even 2-3 years.
I agree with every thing you wrote except the amount of time.
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I agree, too, as long as we don't start that thread again about salt water and Buffalo urine. ;D (-P
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There's nothing more disappointing then getting a 20 year old stave and chasing wasp holes out of it into the heartwood till all you have left for width on the stave is a sliver.Been there too many times.So I always take the bark and sapwood off to a ring and shellack it in moderate type weather.Never been disappointed doing things that way.The only time I delay is if the osage would be harvested in the dead of winter.
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I’ve got a sawmill, and this is how people in the timber business do it. You won’t get checking this way. SEAL THE ENDS. Is the most important part and should be done as soon as possible. TAKE OFF THE BARK. You know why, wasps. SEAL THE SAP WOOD. Then, get a chainsaw and make the belly a plain instead of a ‘v’ shaped wedge, then SEAL THE BELLY. You want to lose moister content as slowly as possible, the only parts not sealed should be the edges.
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One thing that has not been addressed is that since the outside of the tree/stave is larger diameter/wider, there is more shrinkage than in the wood closer to the center. This is why there will seldom be a crack at the point of the pie slice-shaped stave.
The lumber industry deals with this in the form of cupping of boards where the outer surface shrinks more than the inner. It's less about a difference in moisture content than about longer sections of growth rings on the outside of the log and board. This is amplified in a split stave.
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then you get a fence post,, stuck in the ground for 50 years plus,,no care taken,, and there is a bow in there,, osage is a mystery,, (-S
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Here is an oddball theory (completely unfounded) on fence posts; When you stick one end in the ground you may have a ground moisture wicking effect that slows curing to a level that protects the integrity of the post.
Murray Gaskins from Ga, a prolific stave dealer from a few years back, did some testing while felling trees. He found if you dropped a tree with leaves on it and left it for 2 weeks untrimmed, the capillary action of the leaves would wick 40% to 60% of the moisture out of the trunk and cut the overall drying time of staves later cut from the same trunk.
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We used to do Murray's method with maple and ash to get firewood dried faster.
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Funny this came up. Was just chatting with Murray the other day. Poor guy is just "et up" with raptors these days. LOL!