Primitive Archer
Main Discussion Area => Bows => Topic started by: Bkingston216 on November 21, 2015, 05:51:14 pm
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Howdy!
I have a pignut hickory stave in my apartment here in CO, and two bows of the same tree slightly past the roughed out phase.
I bought a moisture meter off Amazon that had good reviews from even woodworkers.
I measured the wood in several places along the stave (which bent the needles due to density) and it all comes up the same 2-3% what gives?
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I've broken those points on those meters before.I don't use them any more.I just take the roughed out bow inside at 50% humidty or lower and keep weighing it till it quits losing weight.I think it's a third longer time after it quits losing weight.The whole process of waiting can take 3 weeks or more.I use the guide in the TTB book to know what the moisture is in the wood at a set humidity.Usually try to get it close to 8% and with hickory you could go down to 7% easily.It'll perform better.
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i also gave up on the moisture meter, I sometimes test the moisture on a new stave that comes in just to get an idea how wet it is but I don't rely on accuracy. I rough out my bows and keep them in a controlled environment for a while. Sometimes the back of my car.
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I can tell a lot about the moisture level by the mass of the bow vs the draw weight. A too moist bow will always weigh heavy, not just because of the added weight of water but it makes them softer in compression.
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The pin type moisture meters only test the wood between the pins and not inside the wood. Drill small holes in the handle area to about the middle of the handle mass. Put tight fitting nails or conductive wire in the holes and put the meter pins to the nails. This should give you a more accurate reading.
I ended up giving my moisture meter away because I never used it. I can tell a lot about the moisture content by sound(ring or a thud) and by the way the tools feel going through the wood.
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The hickory you have may already be below the MC that the meter will accurately read. Some meters have a lower limit and below that MC they are not accurate. Like Beadman, I rely on relative humidity levels and use a kitchen scale to check the weight of the stave. I use a hygrometer/thermometer in my hot box to monitor the relative humidity level and determine the MC of the wood using a wood equilibrium moisture content table....works well for me.
And yes, hickory will perform really well down to 6% MC.......it does much better when really dry.
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I love my moisture meter and use it all the time even though it's a pin type meter.
I get around the fact that it takes only surface readings by using it throughout the bow making process from the first contact with a tool until I string the stave for the first time.
If I get a reading I don't like, I stop and let it dry.
I want 6-8% for hickory.
Bkingston, that is low. Go ahead to floor tillering. Keep checking. Surface readings are often lower and may go higher as you continue.
Jawge
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Once you look into HOW moisture meters work and the different resistances of different woods you soon realize they aren't worth bothering with. You have to spend a whole lot of money to get one that allows you to adjust it for different species of wood.
As mentioned above after a while doing this you will develop a feel for m.c. that doesn't lie! Sound and feel are your friends.
Failing that cut off a small piece of the stave you are working on and weigh it as accurately as possible on some grain scales. Put it in the oven to remove all moisture. Weigh again and work out the percentage of weight loss. = Moisture content. If you cut a small, thin piece it will only take a short time. This method WILL give you a correct reading on any wood and is completely fool proof!
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Is your house humidified? If so it should help your bows stay humidified in dry climates.
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I have never used a pin type meter but have a Wagner pinless model that is a real asset to bow making.
I never adjust the reading for species as I only use hickory and osage for bows, all I want to know is if the wood has reached my areas R/H for dry wood. I know a well seasoned piece of osage will read 12% on my meter so a comparison to a piece I am about to turn into a bow will tell me all I want to know.
They don't make this model anymore but they can be had on the auction site at a fraction of what I initially paid for mine. If you have any problem with one, Wagner will turn it into a new one for you for $99.
This picture is of mine messing up and giving false readings. They don't make things like they used to apparently :), it took me almost 20 years of hard use to wear this one out. I had Wagner fix it so it is back in the game.
(http://img.photobucket.com/albums/v181/ekrewson/bow%20making/moisturereading.jpg) (http://smg.photobucket.com/user/ekrewson/media/bow%20making/moisturereading.jpg.html)
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Well considering I haven't been watching the staves' weight or anything, how would I be able to tell? Weigh it anyway and see if it loses weight in a week?
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And, what scale would you all recommend?
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Cheap digital kitchen scales are amazingly accurate now-a-days. I paid $10 for mine at Canadian Tire. It was on sale, they're about $20 reg.
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Bkingston, I have a digital kitchen scale that weighs in grams, ounces or pounds. It works great for weighing staves.......and many other things. I think I paid about $25-30.00 from Amazon. I also use a grain scale from 3Rivers to do oven dry tests as Bownarra suggested. Done correctly, oven dry tests are very accurate.
For oven dry tests, cut a thin piece of wood that is a cross section if possible. A cut off the surface will not give you a true reading of the entire piece of wood. Weigh the piece on your grain scale and record the weight. Put the piece of wood in the microwave and cycle it for a minute. Weigh it again. Keep doing this until the weight does not drop any more. Subtract the dry weight from the wet weight and divide by the wet weight. Multiply by 100 and that will be your moisture content. If you get the wood so hot in the microwave that it starts to smoke and char, your results will not be accurate and you'll have to start over. Done correctly, this is a very precise method to determine MC of wood.
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Wouldn't I get the same number if I instead: (DRY-WET)÷WET ?
ID get a decimal that easily translates to a percent.
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If you do it that way, you come out with a negative number.
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Actually Drew if I do 8w-10d=-2n
-2÷8=-.25
-.25×100=-25. The way you described first is the way I get the negative number.
But both still reach 25% either negative or positive it doesn't matter.
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But, I can use a piece from anywhere on the stave? Like the pieces that come off with the draw knife from the belly or sides?
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I dont use mine that much, but if i want to know about a stave,, then when I first cut it out or shape it and fresh wood is exposed,, I will get a pretty good reading,, usually at the handle,, if you are roughing it out and the moisture is high, you can bet it is higher deeper in the wood,,, so you know you better coat it again around the handle and fades or it will check,, as Badger suggested, when a stave comes in,, its a good time to check it,, to see where your at,, :)
I live in the high desert now,, and bow making is alot easier than when I lived in the high humidity of Texas and Tenn,, :)
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It's difficult to always get a cross section cut from a stave unless it's extra long, so I do use cuts from the belly or around the handle area. A cross section cut will give you the most accurate average reading though. The moisture content is almost always higher in the center as compared to the surfaces, so if you test a slice off the surface, you won't get a true reading of the core of the wood. Just keep that in mind.