Relative Humidity
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Alan,
IMO, living in Maryland I don't think you really need one.
Two questions:
Do you know how much a dehumidifier costs to run per month in the summer?
It is not cheap. Might as well just air condition your shop, it does the same thing and also keeps you cool. If you go down the road of having a constant wet bulb set point and want to keep your wood in a zone, then you have to humidify in the winter also. By doing this you may cause more problems than you want to solve.
Are you sure you need one?
There is a lot of urban legend stuff in cue making that many people seem to perpetuate and amplify over time. Protecting yourself with dust collection, safety measures with spray booth issues and air purification in your shop should be the top of your list if you have extra bucks to spend.
I know a cue maker or two and no one I know dehumidifies their shop. At least here in the midwest. If your shaft wood has a high moisture reading because you live in a rain forest, then you might want to do it. If you live in a desert you might want to humidify. Those are the extremes environments and need special attention.
After you sell your cues most people are not going to keep it in a controled environment. After your wood becomes a cue it is still wood.
It will be cheaper just use a moisture meter to gauge your shaft wood when you receive it or are purchasing and before cutting squares. I personally have found that you should buy shaft wood that is kiln dried only!!! When ever you can all of the other wood should be kiln dried also. I air con my shop in the summer and I never see my shaft wood go over 6%. When I buy my kiln dried planks they are usually about 5% and increase 1% after they are in my captivity. After they get to my shop I let them acclimate a week or two before I cut squares.
Part of the process is to season your shaft wood over time and IMO that is just to let it happen with the seasons. If you have air con in your shop in the summer and heat in the winter you should be fine. If you feel comfortable so is your wood.
If you are having problems with your cues moving on you, I would suggest building on a core. Movement problem solved!!
Shafts need seasoning over time. You must be constantly buying shaft wood for the distant future. Ernie at Ginacue for example has a minimum 10 year shaft seasoning process going. I am only at 5 years now but I got my eye on the goal. Every time I use 3 dowels, I replace them with 6 on my next batch of shaft wood planks. This way my stock is replace in the "River of Wood" (Diekeman Quoted Term) and increased two fold for higher anticipated sales in the future.
If you have a process and it is giving you the results you want, you must stick to the plan for repeatability. With shaft wood handling, time waits for no man. You must plan for success in the future.
Rick
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Allen,
Here is the relative humidity chart for Baltimore:
http://www.cityrating.com/cityhumidity.asp?City=Baltimore MD
The average daily fluctuation is between 77% and 54% so I think you should set your point at an average of 64%. This is an outdoor average. Indoor averages will be different.
I think take doing nothing will produce similar results because wood takes time to absorb and to lose moisture content so your question needs to take in many factors.
The bigger question is what is the moisture content in you wood.
Good Luck,
Rick
Here is the relative humidity chart for Baltimore:
http://www.cityrating.com/cityhumidity.asp?City=Baltimore MD
The average daily fluctuation is between 77% and 54% so I think you should set your point at an average of 64%. This is an outdoor average. Indoor averages will be different.
I think take doing nothing will produce similar results because wood takes time to absorb and to lose moisture content so your question needs to take in many factors.
The bigger question is what is the moisture content in you wood.
Good Luck,
Rick
IMO, getting properly milled, dried, & stress relieved wood is the key to keeping stable wood. Good wood is paramount & prevents most, if not all, issues. I think cue makers experience things & want to avoid it in the future so they look for logical ways to fix the issues. This why cue makers believe seasoning over time, climate controlling the shop, sealing after every cut, waiting so long between cuts, etc. all result in more stable wood. Fact is, all that does is reveal the crappy wood a little slower & fewer at a time so it isn't so shocking to find that the wood you just bought is crap. Don't get me wrong, I don't see anything wrong with processing your shafts that way. I just don't see it as critical. Over a period of time in building, if you keep up with your yields, you'll find a pretty good average for the particular source you have. No matter how you process the wood, that average will stay pretty consistent. Don't believe me? Try it. Maybe it's all BS & maybe it's not. How do you know? I know because I have been experimenting with it for 10+ years. But don't take my word for it. Find out for yourself.
Point is that stressed wood will warp. It doesn't matter how much you baby it or how long you let it hang, it'll warp. Humidify it, dehumidify it, take a bunch of tiny cuts over several years or make those cuts over a matter of months, the warper wood will warp & the good stuff will remain stable. Your yield will not vary much. Worst thing that can happen is you actually do find a way to maximize your yield while the wood is in your shop, then your customers are the ones who find the warpers. Not good for you, or them.
Properly stress relieved wood is the result of relaxing the wood so that the stress on the shell, surface of the wood equalizes with the core. That has to be done AFTER the wood is dry, especially if it's kiln dried. During the drying process, the wood gets what is known as "case hardened". That means the surface dries faster than the core, and shrinks & tightens around the still wet wood at the core. This stresses the wood, and leaves it stressed even when the moisture at the core equalizes to the shell. It's fine if the wood is going to be used as cabinets. But as soon as the wood is ripped into squares, that stress is relieved unequally, more on the fresh cut edges than on the top & bottom surfaces. This is why it warps. It wants to find stress equilibrium again. No matter how long you let it sit or how long it hangs between cuts, it always has stress & the stress is altered after every cut, making it brand new again.
About 30% of lumber is naturally pretty free of this internal stress due to the cut from the mill. And it's not actually free of stress, just has more even stress so warping is less likely. But the rest not so much. 'Properly' air dried wood has the least amount of stress and is actually nearly stress free. But kiln dried wood is dried too fast & uneven(for cues), resulting in maximum stress. Again, no biggie for cabinets, but utterly unsuitable for cues. The wood must be stress relieved after drying. Unfortunately, it is rarely done & I personally don't know of any shaft supplier that does it. It takes a few extra days and requires an extra process beyond just drying, and that costs money. The closest I know is one supplier in Michigan who knows how to avoid most of the stress by the way he mills the logs & dries the wood, which is also very time consuming & requires a keen knowledge of the particular subject of shaft wood. But no other I know of does it, and even his isn't relieved of stress, just doesn't incur nearly as much stress as the typical shaft processors.
I won't go in to how to stress relieve the wood because it's a science all to itself. But it can be done by the builder once you have the wood. Buy wood from anybody you want & as long as you have the tools & knowledge, you can stress relieve wood on your own. Once the shell of the wood is stress equalized with the core, then you pretty much never have to worry about warp. Sure it can & does happen, but not nearly at the level we commonly know in the shafts bought from suppliers or even cut ourselves from boards. Seasoning wood is all BS. Once the wood is thoroughly dry, time doesn't matter anymore. It's the stress that causes movement, and it doesn't just go away with time.....any amount of time. It's there forever until it's equalized. The more severe the stress, the faster & more severe the wood will move. The less severe the stress, the slower & less noticeable it'll happen....but it will happen.
Sorry for the long post. I see a lot of misconception & mysticism with shaft processing & it costs a lot of guys a lot of money. My advice to anybody is to quit wasting money & time on mystical ideas for treating the problem, & take a scientific approach to curing/eliminating the problem. Or chalk it all up as bullshit & keep on keeping on. There's a reason musical instrument manufacturers have their own kilns to further process the already kiln dried lumber they buy
Point is that stressed wood will warp. It doesn't matter how much you baby it or how long you let it hang, it'll warp. Humidify it, dehumidify it, take a bunch of tiny cuts over several years or make those cuts over a matter of months, the warper wood will warp & the good stuff will remain stable. Your yield will not vary much. Worst thing that can happen is you actually do find a way to maximize your yield while the wood is in your shop, then your customers are the ones who find the warpers. Not good for you, or them.
Properly stress relieved wood is the result of relaxing the wood so that the stress on the shell, surface of the wood equalizes with the core. That has to be done AFTER the wood is dry, especially if it's kiln dried. During the drying process, the wood gets what is known as "case hardened". That means the surface dries faster than the core, and shrinks & tightens around the still wet wood at the core. This stresses the wood, and leaves it stressed even when the moisture at the core equalizes to the shell. It's fine if the wood is going to be used as cabinets. But as soon as the wood is ripped into squares, that stress is relieved unequally, more on the fresh cut edges than on the top & bottom surfaces. This is why it warps. It wants to find stress equilibrium again. No matter how long you let it sit or how long it hangs between cuts, it always has stress & the stress is altered after every cut, making it brand new again.
About 30% of lumber is naturally pretty free of this internal stress due to the cut from the mill. And it's not actually free of stress, just has more even stress so warping is less likely. But the rest not so much. 'Properly' air dried wood has the least amount of stress and is actually nearly stress free. But kiln dried wood is dried too fast & uneven(for cues), resulting in maximum stress. Again, no biggie for cabinets, but utterly unsuitable for cues. The wood must be stress relieved after drying. Unfortunately, it is rarely done & I personally don't know of any shaft supplier that does it. It takes a few extra days and requires an extra process beyond just drying, and that costs money. The closest I know is one supplier in Michigan who knows how to avoid most of the stress by the way he mills the logs & dries the wood, which is also very time consuming & requires a keen knowledge of the particular subject of shaft wood. But no other I know of does it, and even his isn't relieved of stress, just doesn't incur nearly as much stress as the typical shaft processors.
I won't go in to how to stress relieve the wood because it's a science all to itself. But it can be done by the builder once you have the wood. Buy wood from anybody you want & as long as you have the tools & knowledge, you can stress relieve wood on your own. Once the shell of the wood is stress equalized with the core, then you pretty much never have to worry about warp. Sure it can & does happen, but not nearly at the level we commonly know in the shafts bought from suppliers or even cut ourselves from boards. Seasoning wood is all BS. Once the wood is thoroughly dry, time doesn't matter anymore. It's the stress that causes movement, and it doesn't just go away with time.....any amount of time. It's there forever until it's equalized. The more severe the stress, the faster & more severe the wood will move. The less severe the stress, the slower & less noticeable it'll happen....but it will happen.
Sorry for the long post. I see a lot of misconception & mysticism with shaft processing & it costs a lot of guys a lot of money. My advice to anybody is to quit wasting money & time on mystical ideas for treating the problem, & take a scientific approach to curing/eliminating the problem. Or chalk it all up as bullshit & keep on keeping on. There's a reason musical instrument manufacturers have their own kilns to further process the already kiln dried lumber they buy
^^^^^^^^^^^^.....this
It just plain common fact no matter what you do to wood it's going to do what it wants to. Wood is going to swell when it gets in an environment that has a higher humidity than what it is processed in and it is going to shrink on the other end of the spectrum. If you keep it some where in the middle it is going to have less contraction and expansion reaction as opposed to being in an environment such as one where the RH is generally in the low teens to single digits and the finished product ends up in a higher 60-90 percent range. I immediately realized this when I made the move from Michigan to AZ and lost over 20 assembled butts bringing it from an 70-90 to a 9% RH. Some of them shrank over .010 into a smaller diameter without even cutting on them.
If you keep it in the middle it has less size to move....and it will, guaranteed. Wood needs humidity to survive....even after the tree has hit the ground.
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Dave,
Great post and I believe your opinions represrent truths verified by experienced over time.
One point I would like to add is that the company that vacuum kilns my planks in the UP rehydrates the maple after they draw the moisture out as a process control step. Even so you still have to stress relieve wood by taking cuts over time so it can equalize.
Thanks for sharing,
Rick
Great post and I believe your opinions represrent truths verified by experienced over time.
One point I would like to add is that the company that vacuum kilns my planks in the UP rehydrates the maple after they draw the moisture out as a process control step. Even so you still have to stress relieve wood by taking cuts over time so it can equalize.
Thanks for sharing,
Rick
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^^^^^^^^^^^^.....this
It just plain common fact no matter what you do to wood it's going to do what it wants to. Wood is going to swell when it gets in an environment that has a higher humidity than what it is processed in and it is going to shrink on the other end of the spectrum. If you keep it some where in the middle it is going to have less contraction and expansion reaction as opposed to being in an environment such as one where the RH is generally in the low teens to single digits and the finished product ends up in a higher 60-90 percent range. I immediately realized this when I made the move from Michigan to AZ and lost over 20 assembled butts bringing it from an 70-90 to a 9% RH. Some of them shrank over .010 into a smaller diameter without even cutting on them.
No wonder Tad's shafts are famous for being straight.
He has no AC or humidifier.
Just good SoCal climate between the ocean and the desert.
You know like at Disneyland.
You cannot relieve or remove stress by cutting. You can only remove wood by cutting. Time has nothing to do with it, either. All you are doing is removing wood so the shaft can equalize stress by warping, then cutting it straight again & repeating the process, hoping that eventually there'll be no more stress. But it's just hoping. The stress doesn't go away because you cut wood away. At a certain point, it may find equilibrium but the chances that it's at the 13mm point is as good as playing the lottery. There's nothing mystical about wood. It's a well studied & documented science. Just not many cue makers subscribe to & study it.
What Dave is referring to is environmental moisture exchange & is something altogether different, but no less important. He actually addressed the OP's question more directly than anybody. I'm not sure what the OP wanted a dehumidifier for, whether for stability reasons or keeping the wood at a constant medium humidity so it doesn't expand or shrink too much when it's shipped to it's new home. We have two completely unrelated subjects going on here.
Define stress please.
I think it's a term not set in stone.
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I should have been more specific in my original post, but the thread kind of took a different direction which was perfectly OK. Thanks to all the posters thus far. Thanks for sharing your insights and opinions.
Back to the original question and a little more background information. We had hurricane Irene come through here not long ago, followed by days of drenching rain from tropical storm Lee. I was unhappy with the fact that for days the RH in my shop was 80% or more. I turned on the AC many times to bring the RH down, but I do not keep a temperature controlled shop, just AC and heat when I'm working there. In order to not run an AC unit more than neccessary, I elected to run a de-humidifier. One of my big concerns was the machinery that I have in the shop and the likelyhood of advancing rust with high humidity. I totally forgot to mention anything about machinery, so naturally everyone thought I had shaft and wood concerns.
I was thinking that 55% RH was a decent number to reach for, but was wondering where anyone else kept their shop. I know many don't have temp. controlled/humidity controlled enviroments for their woods, I apoligize again for the confusion of my original post.
Thanks,
Alan
Back to the original question and a little more background information. We had hurricane Irene come through here not long ago, followed by days of drenching rain from tropical storm Lee. I was unhappy with the fact that for days the RH in my shop was 80% or more. I turned on the AC many times to bring the RH down, but I do not keep a temperature controlled shop, just AC and heat when I'm working there. In order to not run an AC unit more than neccessary, I elected to run a de-humidifier. One of my big concerns was the machinery that I have in the shop and the likelyhood of advancing rust with high humidity. I totally forgot to mention anything about machinery, so naturally everyone thought I had shaft and wood concerns.
I was thinking that 55% RH was a decent number to reach for, but was wondering where anyone else kept their shop. I know many don't have temp. controlled/humidity controlled enviroments for their woods, I apoligize again for the confusion of my original post.
Thanks,
Alan
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To prevent rust, the shop must be a few degrees above the dew point.
As humidity rises , the dew point approaches the ambient air temp.The lower the humidity, the lower the dew point will be for a given temp.
If the temp gets low enough, even at %55 you can still have rusting equipment.
As humidity rises , the dew point approaches the ambient air temp.The lower the humidity, the lower the dew point will be for a given temp.
If the temp gets low enough, even at %55 you can still have rusting equipment.
For those who wish to learn more on this subject this is a very good book. It is a little technical so it is noy a easy read.
http://www.leevalley.com/en/wood/page.aspx?p=20150&cat=1,46096,46127&ap=1
http://www.leevalley.com/en/wood/page.aspx?p=20150&cat=1,46096,46127&ap=1
I would be willing to bet that you will have movement in your wood (pun intended) at 80%.
My work area is usually 40% to 52%. It takes a little dip in the winter to the mid 30's. I keep an air conditioner on most all summer to keep it even. I don't seal anything. If it is going to move I would like to see it. I have only had a few pieces squirm. One butt warped in the winter and I left it hanging until summer and it straightened out. I cored it while it was straight.
I live near Athens Georgia. Athens is about 80 miles north of Macon. That is where they start having the hair grow in the trees because the humidity is very high all summer. We don't have extreme humidity here except if it gets rainy. Most of the summer it is 55% to 65%. If it gets hot and dry, it drops to 35%.
You can have humidity that is too low and it is just as bad as too high. Wood will shrink and move at a very low humidity and swell and move at a very high humidity. It is best to keep it at a relatively stable level somewhere between 40 to 55 percent.
just my opinion
Kim
I have been in south Florida for over 20 years and never used a dehumidifier. In the summer, the dew point is never ever below 70 degrees and the relative humidity runs around 90% every day. My work area is air-conditioned from May through October and the wood storage room only gets A/C when I leave the door open. The rest of the year my shop has open doors all the time. I don't check R.H. or wood moisture content.
The only thing I do do is take a long time with the wood. Shafts get a turn everyApril and handles and fronts during the summer. Any wood that warps a lot once gets trashed as does any wood that twice moves even a little between turnings.
I would really avoid always keeping my shop at a constant R.H. unless I could be sure that the cues I make would always be in the same atmosphere. Twice in 20+ years I have had a shaft move when it got to its new home but in each case, within a week the shafts had returned to straight. Varying conditions over time produce well seasoned wood.
If it is so damp that iron rusts, the dehumidifier is a good idea but as mentioned it will be expensive to run all the time. If it doesn't feel too muggy for you, it probably isn't too muggy for the wood either.
The only thing I do do is take a long time with the wood. Shafts get a turn everyApril and handles and fronts during the summer. Any wood that warps a lot once gets trashed as does any wood that twice moves even a little between turnings.
I would really avoid always keeping my shop at a constant R.H. unless I could be sure that the cues I make would always be in the same atmosphere. Twice in 20+ years I have had a shaft move when it got to its new home but in each case, within a week the shafts had returned to straight. Varying conditions over time produce well seasoned wood.
If it is so damp that iron rusts, the dehumidifier is a good idea but as mentioned it will be expensive to run all the time. If it doesn't feel too muggy for you, it probably isn't too muggy for the wood either.
Not set in stone by cue makers, but well defined & known in other wood working industries. Stress is the internal tension inside the wood that causes it to curl, cup, warp, crack, etc. It happens when the outer surface of the wood dries before the core, and the shrinkage of the shell compresses the core, thus creating tension. In a mild but exact way, it's like a compressed spring. You ever see mud dry up & crack & distort/curl up around the edges of the cracks? That tension of shrinkage due to moisture loss is what causes the cracking & distortion. No different in wood, except that the wood fibers are bonded together & resist cracking, unlike dirt. So instead of cracking, it warps. Just like fruit withering up as it dehydrates. It alters the shape, and until that shape can be altered, the tension remains. That is stress. It doesn't go away by cutting. It is revealed by cutting. It can only be relieved by equalizing the core of the wood with the surface of the wood.
Here's a round about explanation of stress, easier to understand than my explanation. http://www.modernwoodworking.com/article/conditioning-relieving-those/1112
even better : http://www.modernwoodworking.com/article/conditioning-relieving-those/1112
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Ignorance is bliss. When I started, I had no ideas about wood. Stress, shrinkage, warpage were something I had no knowledge of. BUT, through the years I wondered WHY some pieces moved & others did not. They were cut at exactly the same interval & from the same board. I discovered that the blanks cut from the interior of a plank all reacted the same. They were more stable & required less time between cuts, to keep them from moving. Then I examined the grain & structure of the planks, that I was buying. I discovered that, WHERE the blank is cut from, in the plank, makes a difference in how it reacts to the enviornment. Younger cuemakers buy their wood in 2x2 squares or rounds & have no idea where, in the tree this piece has come from. Such a pitty. You are left to the whims of the seller. My advice is to buy wood that has the longest hang time that they can buy. For example the wood that I am using to make cues today was bought 10 or more years ago & stored in a natual enviornment, with no artificial outside influence from humidifiers. My wood lives WITH me. When I need the airconditioning on, it is also effecting the wood. Maybe I'm still in the dark, but MY cues don't warp. There must be something to my ignorence...JER
P.S. qbuilder... You & I agree on nearly everything, that has to do w
ith the wood.
P.S. qbuilder... You & I agree on nearly everything, that has to do w
ith the wood.
Great read. Thanks.
Athens is a great place. I moved here from Syracuse 16 years ago. I hate to go back even to visit.
Kim