Primitive Archer
Main Discussion Area => Bows => Topic started by: Stick Bender on October 02, 2016, 01:56:19 pm
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Hi Fellas with getting rained out for hunting this week end figured I would play around with building a drying box but I'm remodeling my upstairs & have every square inch of space just about in our spare bedroom /junk room taking up ,came up with this Idea I know in Adam Karpowitz horn bow book he warmed bow limbs before bending with a electric blanket so I'm trying a experiment ,the stave I'm trying it with is osage about 13 months off the stump I weighed the stave in grains & wrapped the stave in paper towels and loosely wrapped it in the blanket & set the temp to 92 F I'm going to run the blanket for 10 hrs a day for a month and re weigh ,the blanket has a 10 hr timer you can't over ride any body got any tips on force drying ? I figured it would be safe with this stave as prior to trying this this stave hung in my shop that averaged well over 100 F in the summer.
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I would put another thermometer in there until you're sure it's not getting too hot. Sometimes when you wrap things like that in multiple layers they can get hotter than you expect. I guess it would depend on where the blankets thermostat reads from.
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Has the stave been roughed out into a bow or is it still a full stave? It seems that if the stave is 13 months old and you've had it in you shop this summer at 100°, you don't need to dry it much more. Have you been monitoring recent weight loss? It should be minimal at this stage. If you do keep it in your blanket wrap, I would monitor it every few days. You don't want to get it too dry. It's osage, not hickory.
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No it's not ruffed out other than 1 5/8 In. Wide & 1 1/4 In. Thick I'm just trying to get the final moisture out made one last year that was a year off the stump & it picked up draw weight after about 5 months after it was made just trying to avoid that on this one I plain on letting it acclamate as I work on it & before long string.
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I'm actually lifting the blanket and reading with the infrared thermometer I think these blankets temp is controlled by the amount of voltage/current that's put to them in the controller as far as I can tell it doesn't kick on & off plus it's only running 10 hrs a day then resting 14 hrs
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A whole month of drying, after it was cut 13 months ago? My hazel bows are after initial reducing while green completely dry now. It was about 5 weeks, next week I will be tillering them.
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At 13 months off the stump, you can really push the limits without causing any checking. You have already lost a majority of the water in that stave and now you are just cleaning up the final percentages.
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Why don't you rough your limb thickness down for final drying? No need to dry wood that you're going to remove.
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I'm probably not going to have time to work on this bow tell late November so figured I would dry it out some now & let it reaclamate to ambient conditions if I had had more time I would have thinned it down some.
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I'm not sure if water + electric blanket= disaster.
Just a thought.
Jawge
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I wouldn't even fool with the electric blanket. 13 months off the stump you are pretty close to equilibrium for your location. I would rough the bow out and them maybe a couple of days in a hot box. Most of the staves I buy are green and wet, I rough them out about 6 months after being split then let them sit for a few more weeks before final tillering.Sometimes I use my car as a hotbox. I have had osage continue to gain some weight for up to 10 years after finishing. I think the wood seasons and gets harder. I have had other osage bows never change weight after final tiller so it is hard to tell what is really going on.
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I realize that you said that there was not enough room at your place for a proper hot box, and most of the advice seems to favor a box rather than the blanket.........
I have somewhat the same situation here, and have taken a 2' x 8' styrofoam board @ 1" thick,ripped into 2 pieces
1' x 8'. it is horizontal with an old florescent light fixture inside. 2 bulbs = 100 F. < 5% RH
would fit above door on 2 cheap shelf brackets or similar if you are creative enough
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Good luck with your wood drying!
Adam doesn't say to warm hornbow limbs before stringing though! This would cause set in the braced bow. ;)
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Yep your right Mike should have said before tiller corection, Willie I went to the big box yesterday & was looking around at ideas but nothing would seem to work in that space was looking at 6 " pvc pipe but to heavy the only other space I have right now is next to bows & staves as shown so was looking just for temp drying I also have a hickory stave I want to try ,Steve thats interesting about the hedge & gaining weght maybe Im chasing the wrong tail
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If the electric blanket is rolled around the bow, the blanket itself is going to get pretty hot. All the heat from all the elements is going to be trapped. When in normal use, each element section is able to radiate its heat into you or out above you.
You could end up building a new house instead of remodeling.
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Yes but even at that on low setting it's 92 F on the inside ,it's ok for drying more seasoned staves but would not work for greener wood like I said I'm more or less trying a exsperment I had high hopes it would be more controllable for lower temps but not so , so for this stave and another more seasoned ruffed down hickory stave 7 months of the stump I'm ok but for any thing else I would have to build a proper hot box but after these are done I won't have to much of a need as I have a pretty good stash of seasoned staves now just trying to get threw the winter with these.
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I had high hopes it would be more controllable for lower temps but not so
a lightbulb dimmer should work if it is rated for the amperage.
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If any body is interested the results of my first exsperment is the osage stave was in the blanket for 6 days for 10 hrs a day with a average Temp. Of 94 F @ 50% humidity and after weighing today it lost 20 Grains of weight I'm drying a hickory stave now doing the same test.
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20 grains ain't much. Roughly 15 grains to a gram. I would say that it wasn't worth it. Maybe the excess moisture can't get out or like Badger said maybe it was already dry enough.
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Yep didn't expect to lose much just been so rainy & humid here this year wanted to squeak some out I'm more interested in seeing what the hickory will do ?
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Once the hickory is dry it would be interesting to put the two of them in a humid room and see just how much faster the hickory gains weight.
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That would be interesting but we both know which one would win but if we properly sealed both they would be close I would bet ?
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Ok so here is the results of the hickory test the stave is a 1 in. Thick ruffed out bow that's about 6 months of the stump & has been inside for about 5 months @ 52 % humidity I put it in the blanket @ average temp 103 F @ 50% RH for 90 hrs. It lost 39 grains of additional weight ,now I'm letting them rest for 1 month & re weigh , I know this is kind of a hair brain exsperment but I don't have a moister meter & if they stay the same or gain a little weight I will fell confident there at ambient moister.
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stickbender-
not trying to be picky, but when you say....
I put it in the blanket @ average temp 103 F @ 50% RH
I am presuming that the 50% refers to the humidity in the room, before wrapping in the blanket. RH, (relative humidity) is relative to temperature, so if you want to know the actual RH at 103 F you can consult a Psychrometric Chart. the difference between rh at the elevated temp and the rh at room temp, is what determines how fast the moisture leaves the wood
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Yep I was speaking to the room RH I have no way to determine what it is in the blanket ,also don't own a moisture meter so just doing it by weight . Just trying to make sure both those staves are dry ,most of the wood I have worked with has not been real seasoned so wanted to make sure these where dry for winter work.
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You'll get what you want Ritch.If it gains a little weight at room 50% humidity out of the blanket you'll know what's going on.It'll be exactly what the chart says.Good to know what your getting into before removing wood.
Hedge'll take longer for humidity to infiltrate more so than most woods because of the density you know,but then it'll take longer to leave then too.