Primitive Archer
Main Discussion Area => Bows => Topic started by: JoJoDapyro on April 22, 2016, 02:03:26 pm
-
I see people say a lot that wood is "Too Dry". Is this a thing? Without heating wood, shouldn't it be somewhat close to relative humidity of the area that you live?
Here in Utah it is about 60% in the winter, and in the low teens in the summer. Speaking in terms of lumber, HD and Lowes are cooled by swamp coolers, adding humidity, and thus moisture to wood in the summer months. Is "Too Dry" just a flawed way of saying that a wood has some sort of rot happening?
-
Most bow wood are ideal for building bow at 9%-11%, hickory 5%-6%. In areas of dry relative humidity bow wood can get too dry and is subject to exploding when stressed. In dry areas hickory makes a very good bow wood.
Rot occurs when the moisture content is high. Rot(mold, fungi) needs moisture to survive.
-
I get that pat, but with a relative humidity of 13%, how is the wood getting "Too Dry"?
-
What is the moisture content of the wood with the R/H at 13%?
-
My basement hovered around 37% this winter unless I ran a humidifier.
-
I get that pat, but with a relative humidity of 13%, how is the wood getting "Too Dry"?
I think you're confusing MC with RH
http://www.csgnetwork.com/emctablecalc.html
-
It would make sense for MC and RH to arrive at equalization but they don't unless temp is high enough for the respective species
-
I found Utah was too dry when I went through there, I had just hitchhiked from Moab to outside salt lake, found a spot to sleep and then walked to get a couple 40's and relax under the stars, 3.2%! Might as well have been drinking coolaid I was mad haha
-
I found Utah was too dry when I went through there, I had just hitchhiked from Moab to outside salt lake, found a spot to sleep and then walked to get a couple 40's and relax under the stars, 3.2%! Might as well have been drinking coolaid I was mad haha
Isn't it lovely?
I get that pat, but with a relative humidity of 13%, how is the wood getting "Too Dry"?
I think you're confusing MC with RH
http://www.csgnetwork.com/emctablecalc.html
How can something dry to below the current level of ambient humidity? If there is a scientific explanation I know someone here can explain it.
This is my thought. If the relative humidity is 5%, given enough time a woods moisture content could fall to 5%, but if the relative humidity is 13%, then how can wood get below that point?
-
I get that pat, but with a relative humidity of 13%, how is the wood getting "Too Dry"?
I think you're confusing MC with RH
http://www.csgnetwork.com/emctablecalc.html
Does this calculator show the true moisture content, or the difference between the equalized moisture content and the relative humidity that the wood has been stored at?
-
Now you've got me questioning myself. :D I just use the chart, I skip over the math. I made the assumption that 10% MC meant that if the bow weighs 10 oz, 1 oz is water. I may be wrong. This doesn't equate to 10% RH. When the RH and MC are such that water is neither evaporating from, nor being absorbed into the wood then you have EMC. I'm not sure if this is helping or not.
-
Relative humidity and moisture content are two different things. Relative humidity is the percentage of moisture in the air based on the temperature. Say it's a hundred degrees outside with 100% humidity that is completely different than 40 degree air with hundred percent humidity. The warmer the air the more water it can carry. As for moisture content moisture content is the percentage of water. Hundred percent relative humidity is not like 100% moisture content. Hundred percent moisture content would be the equivalent of a lake. Obviously air cannot carry saturation like that. Relative humidity is nothing more then a percentage based on what a certain temperature of air can carry. That is why during the winter when it's 30 degrees outside and they say it's 70% relative humidity you feel like your skin and nose is dry. But if it was 90 degrees outside with 70% humidity you be sweating and feel sticky. I hope that makes sense
-
measuring the moisture content of the bow wood would be better than trying to guess how dry it will get in a low humidity,,
if your bow has not exploded, it is probably not to dry for the type of wood,,,, if you have a relative low humidity in your area and your bow is stored in the heated house with even lower humidity,, your bow could get to dry,,
-
That is why during the winter when it's 30 degrees outside and they say it's 70% relative humidity you feel like your skin and nose is dry. But if it was 90 degrees outside with 70% humidity you be sweating and feel sticky. I hope that makes sense
Living in the desert, we don't know anything about high humidity. When its 100 and 20% we're dying here.
-
"How can something dry to below the current level of ambient humidity? If there is a scientific explanation I know someone here can explain it."
The full answer is beyond my knowledge of chemistry, but basically, it's because the warmer air gets the more water likes air, while the opposite is true of wood. Water evaporates OUT of warm dry wood into warm, dry air, but warm moist air already has enough water, so the water stays in the wood.
We're neighbors, of course, and one of the things I love about Utah is that my wood is almost always dry enough unless I just cut it. Several years ago we had a warm, wet spring, well into June, and I couldn't figure out what the heck was wrong with all my wood! It acted so weird.
I have had wood get too dry after it sat in a hot car in the summer, and in the garage rafter space. But even then it didn't blow up, it just worried me.
-
I dry all my hickory indoors for months after roughed out...In Ga. you have to ..hickory will not get below 15% outside..anytime I work it , it goes back in the closet till next session...when done it gets sealed pronto..Since its so abundant and makes a screamer bow it is now my favorite wood..just takes a while to get it dry ..love that hickory!!!...gut
-
My standard measure of how dry my woos is, is holding it up to my face. Kinda like searching for dry firewood.