How dry is too dry?

[Pat B]

Was the tree dead standing?

[Mesophilic]

I cut down the middle of the broken limb, and just like before it is coming up 3%.

The meter might be off, but the wood is very dry and splintery.  Even if the meter is off by quite a bit this wood  still seems extremely dry.

What does it say if you stick it into a damp towel or a green stick?

On the hardwood setting a damp paper towel says 35%.  On softwood  it says 100%.  Masonary 72% and Wall 100%.

Was the tree dead standing?

That I can't say, I got some staves in trade.

[DC]

On the hardwood setting a damp paper towel says 35%.  On softwood  it says 100%.  Masonary 72% and Wall 100%.

Well it ain't stuck on 3%. I don't really know how they work, don't know why "hardwood" would be so much lower.

[Mesophilic]

I refer to this chart a lot.  I monitor temp/humidity in the place where my wood is stored and it corresponds to this chart pretty well.  Like DC mentions, I would estimate it takes a week of constant higher or lower humidity to make the MC change any noticeable amount. 

Your humidity would have to be around 15% to get down to 3% MC.

We get regular intervals of single digit humidity.  We have a storm right now, but when it gets back normal I'll definitely reference this chart.

I'm pretty sure I'll have to rethink my bow making strategy and this explains alot of my frustration.

Would sinew or rawhide change the tension on the bow back to a safe zone?  Here's what an engineer friend of mine texted me on the topic, I won't paste the whole conversation  but he believes it's tension and not compressikn that makes a bow fail when too dry.

Wood fails under tension when you bend it.
You are literally tearing the matrix of cellulose fibers apart in much the same way you would tear a muscle when exercising too hard.

The drier wood shrinks radially, which pulls the bundles of cellulose fibers in tighter together. So under tension and bound closer together they don't have as much ability to slide across each other and/or get out of each other's way. This adds extra stress to the fibers and causes cracks to form.

Imagine a bundle of dry spaghetti noodles. If you grip them loosely they can bend as a bundle. But when you grip the bundle tightly and bend it, it is more prone to snap in half. Same thing goes on in wood.

Drier wood is like the tightly bound bundle of spaghetti.

[Selfbowman]

All I know is a well made bow built at 7% sent from central Tx to Utah don't last long in a experienced archers hands. Osage by the way. Arvin

[Badger]

Wood looses tension strength as it dries but gains compression strength up to a point. below 6% I believe it starts to get weaker in compression as well. Almost all of the bend is because of it compressing. Wood has very little stretch to it.

[bradsmith2010]

If the room is heated and dry,,,it will dry the wood more

[Mesophilic]

If the room is heated and dry,,,it will dry the wood more

Yes, one of my compounding problems.  The snow partially collapsed the roof on my tin shed and now it leaks like a sieve.  So i brought alot of things into the house.  I put the staves in a closet in our extra bedroom tha naturally  stays colder than the rest of the house due to an ancient snd not well thought out duct work system.

For the last week we've had a weather system so I can't give normal current stats, but last year this time our highs would be in the upper 70's with about 25% humidity in the a.m. dropping.to single digits by the afternoon.  Most of last summer was 8 to 10% humidity range.

The museum pieces I've seen, the local natives used alot of sinew backing and the climate was a little wetter back then, too.

I'm pretty sure my only hope lies in appropriate backings.  I've had issues with sinew drying too fastand ripping apart the  back of the bow.  I think I'll give it another shot when the weather warms up enough to start running the swamp cooler.  If that fails, I'm leaning toward rawhide backing.

[RandyN]

I've had a couple bows fail here in Santa Fe that I am sure was because the wood was too dry. My latest bow, made from an old fence post, was heading in the direction of failure so I put a rawhide back on it and it shoots nice. I was getting splitters on that bow and that is why I figured it needed a backing. First time i used rawhide and it worked great.

[willie]

I'm pretty sure my only hope lies in appropriate backings.  I've had issues with sinew drying too fastand ripping apart the  back of the bow.  I think I'll give it another shot when the weather warms up enough to start running the swamp cooler.  If that fails, I'm leaning toward rawhide backing.

drying too fast leaves surfaces drier than he inside, whether natural or backed. perhaps a strategy is to make the back wider, as it is usually the back that fails first.

tension qualities get better as the back gets drier to a point (pat mentioned different numbers for different woods), but tension capabilities drop off as the wood gets drier, while compression qualities just keep getting better, overpowering the back

another strategy might be to never bring the bow into a heated space once you are happy with the tillering job, as the relative humidity levels are lower outside. or maybe even measure poundage at some benchmark draw length and double check before shooting if you think the bow may have had a chance to dry out.  an increase in poundage is too good to be true in this case

[bradsmith2010]

Yes overbuild,,,to be safe,,.longer wider

[Pat B]

Store it in the bathroom where a shower is.

[DC]

Or a closet with a bucket of water in it.

[DC]

I've often wondered about using a gun safe. Are they tall enough?

[rps3]

If that is the wood I sent you it wasn't standing dead for sure. I have had only one osage bow break and it was my son in-laws bow that he stored in his new house with a fancy heating and cooling system that results in very low humidity levels. I'm betting that is the problem. I couldn't imagine single digit levels. I wish I had some advice on what to do differently, but I hope you figure something out.

Now that I give it a little more thought, I just broke another osage bow, but it clearly broke on an area of the back where I let the heat gun burn the back too much.