Author Topic: Beyond Bone Dry!  (Read 475 times)

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Offline ssrhythm

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Beyond Bone Dry!
« on: July 09, 2024, 06:39:55 pm »
I'm in SE Wyoming.  The last successful bow I made was in the summer of 2021.  It was Osage, and the MC was registering at 6% when I started carving it.  I took a full year off after making that bow.  Since then, all my attempts have ended with back splinters popping, and just two days ago, a 35lb osage flat bow I made for my son just exploded during the draw on shot 30.  So...some back failure and now a sudden and violent compression failure explosion with no warning. 

I realize that these failures could be due to many factors including my relative lack of bow making experience, but bows 2-7 were successful, and shoot well to this day...everything after, failure.

The RH here from June thru September averages <10% during the days and peaks at around 30% most nights.   This upcoming week, the RH is going to bottom out and be at 6% or lower for most of the days and will be less than 30% at peak RH during the night.  All my staves were collected at the same time or before the stave I made my last successful bow from back in 2021 and have been stored on a hanging rack in my often open garage ever since.
 
According to the TBB  relative humidity : equilibrated MC of staves chart, bows will equilibrate at ~6% MC in a climate with average RH of 30%.  I think I read that correctly.  SO.......

Are all my staves useless?  Can staves that are dried to well below 6% MC be rehabilitated and rehydrated to 6%-9% MC and made into safe bows successfully?  Can I increase my length and limb width proportions and aim for lower draw weights and successfully and safely make a bow...a safe bow...out of these extremely, extremely dry staves?  I don't ever want to experience the explosion at full draw deal ever again!

I have a roughed out, really sweet stave/bow in my bathroom, and I'm keeping it steamy in there hoping it will pull in enough moisture to get back between 6% and 9%, but I'm worried the wood got so dang dry that there may be irreversible damage...but I don't know one way or another.  Any opinions on this and advice for salvaging the 15 to 20 osage staves that are currently hanging in my garage?  Any and all advise will be greatly appreciated.

I have a new bow shop that is 24 X 14 and is well insulated and tight.  I will be moving my future cured stave storage out there and will try to figure out a way to maintain an appropriate RH in the shop that will allow me to store and maintain fully dried staves at 6% to 9% MC.  I have no clue how to go about this either, so if anyone living in a similarly unbearably dry climate has figured out the best way (and preferably affordable way) to maintain a shop's RH fairly accurately at 30% to 35% while maintaining a comfy temp when its hotter than hades and dryer than a chip outside...I'm all ears and appreciate your advice.  Thanks in advance for you input.
 

Offline Hamish

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Re: Beyond Bone Dry!
« Reply #1 on: July 09, 2024, 07:01:53 pm »

I'd be interested to know what design you used, and the width and length of the bow? Making a wider and or longer limbed bow will improve your chances of stopping breaks due to low moisture content.

No your staves are not useless, and if you move them to a different environment, they will reacclimate to the new conditions.

With your current conditions hickory is your best choice for an all wood bow. As the one's you have are osage, you have the option of sinew backing, which will make them safe in your environment. You are in an ideal situation for a sinew backed bow.


Offline superdav95

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Re: Beyond Bone Dry!
« Reply #2 on: July 09, 2024, 07:53:17 pm »

I'd be interested to know what design you used, and the width and length of the bow? Making a wider and or longer limbed bow will improve your chances of stopping breaks due to low moisture content.

No your staves are not useless, and if you move them to a different environment, they will reacclimate to the new conditions.

With your current conditions hickory is your best choice for an all wood bow. As the one's you have are osage, you have the option of sinew backing, which will make them safe in your environment. You are in an ideal situation for a sinew backed bow.

Well said hamish.  This is what I would suggest as well. Hickory is tuff.    Also consider a good yew stave and sinew combo or just rawhide backed.  If you can get some leg sinew and try the tb3 option as the bonding agent of you donít care to get neck deep into hide glue.  Iíve had some good results with sinew and tb3 holding up well and performing quite good.  Just some ideas for ya. 
Sticks and stones and other poky stabby things.

superdav95@gmail.com

Offline ssrhythm

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Re: Beyond Bone Dry!
« Reply #3 on: July 09, 2024, 08:20:20 pm »
Hammish, I'm going to SC in August to visit my family, and I have access to thousands of acres of forrest, some of it is virgin, never cut.  My bud will let me cut what I want, and there is plenty of just about any tree you can think of that grows in the SE.  I'm planning on cutting a hickory or two, maybe an elm, and some hop-hornbeam.  I've never wanted to build hickory bows for sluggish moisture reasons, but now that I'm out here seeing what this weather is like, I want to make some fire-hardened hickory bows for sure.

To be fair, all the Bows I've had fail over the last couple of years have been attempts at turning a few of my lesser staves into something great...and I've pushed the limits on all but one.  I overbuilt the heck out of one...very long and wide with a draw weight of just over 50 lbs...and it still popped a splinter.

The bow that exploded was the first to fail in compression...no ticks, no set, no indication anything was wrong till I was standing there holding nothing but a limp string and trying to assess if I was OK without moving.

It was 62" long, stiff handle, top limb 1.5"  longer than bottom.  Approximate width of just under 1.5" from fades to start of taper then even taper to tips.  Parallel max width portion of limbs was ~11' then the taper.  ~ 6" of stiffer tips that were reflexed to just shy of recurved, and the tips were working some.  1/8' positive tiller, and the bend looked great.  I was using a 12 strand b-50 string and bow was pulling 34.7# at 27"...my 12 yo son's freakishly ape armed current DL.

The stave looked flat before backing, but when chasing a ring, the sapwood dove down toward the belly and ran almost center down the length of the bow.  It basically looked like the reverse of a hollow-limb bow.  Basically, it was a "hollow-back" bow, and I tried to keep limb thickness even across the profile by rounding the belly (convex) to approximate the concavity of the back.  I'm sure I was not perfect with this endeavor...but close, and the bend was beautiful.

The main issue beyond the hollow back was that the furrow that ran pretty much center down the length of the back of the bow...well, it ran off the side of the bow about 1" before the reflexed tips began.  I made the area as stiff as the tips hoping low tension here would prevent popping a splinter.   The run off caused some twist on each limb in opposite directions at rest, but at brace, the limbs twisted into perfect alignment and stayed that way during the draw

I didn't think I could pull it off without popping a splinter at one of the limbs where this furrow or ditch jogged off the side of the bow, but after making it and tillering it and putting an initial 20 shots thru it, I was thinking that I had pulled it off...I figured it might eventually lift a splinter, but I'd just glue it and sinew back it if that happened.

It was a great bow for ~29 shots.  The failure originated In the weaker top limb right in the center of where the dip ran off the side of the bow.  I realize I was pushing an iffy design on an iffy stave, but when it failed, It blew pieces of osage all over the driveway. 

I'm going to try to gently rehydrate all of my staves.  I'm going to overbuild until I see some moisture content above 6%.  I appreciate your input.  I just need to pull the reigns on my ambition sometimes, as I was definitely hoping to magically defy the laws of physics on this last disaster.

Offline ssrhythm

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Re: Beyond Bone Dry!
« Reply #4 on: July 09, 2024, 08:37:18 pm »
I have a 63" osage recurve currently pulling 65,8# at 27" that I built in 2021 for my first elk hunt.  I sinew backed it and put some SC copperheads over the sinew.  It is smooth shooting and hard hitting.  I did not want that much ass, but once I got it shooting darts, I was afraid to keep screwing with it.  I've built up to where the ~66# feels a comfy as my 54# trad bows felt before I built the bow.  If I had my way, I'd sinew back every bow I make, but the time and mess and hassle...well, that aint happening. 

I have a sweet 65" osage recurve that pulls 54# or 57#@ 28" (its in SC and I can't remember) that I built the year prior.  It was a sweet self bow until I gouged the back while crawling across a rocky cow pasture on my hands and knees looking for blood from a nice buck that I had just made a marginal hit on...to be fair, I was on the ground and the deer looked my way as I was reaching full draw and he jumped the string immediately by sight and not sound.  Regardless, it was a poor hit, and I spent hours crawling in the pasture, and a rock gouged thru most of the back ring.  I backed that bow with rawhide, as I was worried it would fail at the gouge otherwise.  Rawhide was really thin, but the performance lost due to the weight was enough that I won't back with rawhide again if I have time to do sinew.  Maybe I needed to sand the rawhide even thinner.

Some vids I've watched lately showing some incredible success with fire hardened hickory...even the tree to bow in 12 hours one...those vids have really made me excited about making some hickory bows for use out here in the midst of hell.  Naaa...Wyoming is awesome and  I'd rather have staves dry too much too quickly than to have to wait 12 years to hit 12%.  Still, I think hickory will be a great choice for hunting out here...especially in the early season.
« Last Edit: July 09, 2024, 08:42:02 pm by ssrhythm »

Offline Hamish

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Re: Beyond Bone Dry!
« Reply #5 on: July 09, 2024, 10:23:54 pm »
"It was 62" long, stiff handle, top limb 1.5"  longer than bottom.  Approximate width of just under 1.5" from fades to start of taper then even taper to tips.  Parallel max width portion of limbs was ~11' then the taper.  ~ 6" of stiffer tips that were reflexed to just shy of recurved, and the tips were working some.  1/8' positive tiller, and the bend looked great.  I was using a 12 strand b-50 string and bow was pulling 34.7# at 27"...my 12 yo son's freakishly ape armed current DL."

Yep, it's a little narrow for your low humidity. I'd try 1&3/4" or even more for osage and see how you go. Even a 2-2&1/4" wide pyramid osage would be a good option.You could also make the overall length 64-66" for an extra margin of safety.

You probably won't even need to fire harden to get great results with hickory in your climate.

Another option is to back your osage with a good hickory or boo backing strip.

Online Muskyman

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Re: Beyond Bone Dry!
« Reply #6 on: July 11, 2024, 11:14:15 am »
Could you put your Osage in a room with a humidifier? Staves and bows both. Then just keep an eye on there moisture content to see how much moisture they need in the room. Just a thought I had. Hickory does make a good bow if you want to go that route. Fire hardening does help with it absorbing moisture but you can over do it if youíre not careful.
Good luck

Offline Doug509

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Re: Beyond Bone Dry!
« Reply #7 on: July 13, 2024, 12:37:42 pm »
I've been having similar issues with pacific yew staves breaking at only 40lbs draw weight during tillering. I tested moisture in a 6hr vacuum oven and found moisture ranges from 3.5 to 4.5%.   May have to move my stash to the bathroom shower or apply sinew.

Offline Pat B

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Re: Beyond Bone Dry!
« Reply #8 on: July 13, 2024, 01:21:31 pm »
Does your house have humidity control with the a/c? At what r/h is inside your house? If high enough your bow wood should acclimatize over a week or two. Most bow woods like to be between 9% and 11% m/c. Hickory preforms best at 5% to 6%. In your environment hickory should be perfect and make a damn fast bow.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline ssrhythm

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Re: Beyond Bone Dry!
« Reply #9 on: July 14, 2024, 02:14:10 am »
Ok...I have no idea what our inside RH is, but since we are running central AC in the summer, I'd think it is lower than the outside RH...but I'm not sure.  I've ordered a hygrometer for my shop, and I'm looking into the best humidifier set up to be able to maintain a desired RH of 30-40% in that sized room.

I pulled down another stave, and chased a ring the day after the bow-explosion.  I've been keeping it in my bathroom with the AC duct off in there, and everyone I take a bath, I leave the water in and have been suspending the stave over the water unless I'm working it.  I now have it worked down to where I'm about to start tillering.  The bow/stave is again in the bathroom, and it's good and humid in there.

I have a pin style moisture meter that read the moisture today before I started thinning down the limbs at 6-7%.  I just broke one of the pins off trying to get it to sink in the osage a bit, so I'm looking for advice on a better way to go.  Will a painless meter work on bow staves or does it have to lay flat on a flat piece of wood.

Anyway...the biggest factor causing that bow to break, I believe, was that it had a concave furrow running the length of the stave on the back that ran off either side about 10 inches from each tip.  After reading up on how hollow limb bows actually work...ie the curve actually flattens out as the bow is drawn...I now understand that there was tremendous strain in the center of that furrow where it ran off the edge of the limb.  It's clear as day that the failure initiated at that point on the top limb, and when it did, the ultra dry wood just blew all the way back to the fade. 
 
Hopefully, a more normal, flat backed stave with a bit of re-humidification will result in a bow that won't blow.

Online Muskyman

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Re: Beyond Bone Dry!
« Reply #10 on: July 14, 2024, 11:59:37 am »
I recall seeing someone saying they help hydrate their bow by rubbing a damp rag over it. Donít know if or how much that might help but it sounds reasonable.
Hope things work out for you with your next build.

Offline bentstick54

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Re: Beyond Bone Dry!
« Reply #11 on: Today at 01:11:14 am »
I bought an inexpensive cold air humidifier from Walmart that I run in my basement work room during the winter when the forced air gas furnace is heating the house. It helps me keep the RH in the appropriate 10 x 30 room in the 35% to 40% range.

Offline Eric Krewson

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Re: Beyond Bone Dry!
« Reply #12 on: Today at 10:20:46 am »
My memory may be wrong, my best friend went to the first Mojam, they had a bow speed contest, my friend said That Tim Baker brought a hickory bow that had been dried out to the max and stored in a way to keep it from absorbing moisture, his bow beat all of the other bows as the fastest bow.

The next time my friend went to Mojam he took a sinew backed bow (can't remember what wood) but took a vacation around the southeast on his way to Mojam and really dried out the sinew, his bow was the super performer that year.

I am with Pat on this one, hickory would love the dry environment you live in. Where I live the relative humidity is 12% so hickory is just OK, nothing special and actually a bit sluggish.

Offline bassman211

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Re: Beyond Bone Dry!
« Reply #13 on: Today at 11:21:43 am »
Were you live hickory should be very good, but a well tillered  slightly over built sinew backed Osage bow should survive for a life time in any region of the world.