# Rough cut lumber drying time?



## MasterSplinter (Jan 12, 2013)

I am using a piece of rough cut pine. The saw mill said it was cut about a month ago. It is in my basement. How long for it to be dried? When can i plane it?


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## Dominick (May 2, 2011)

What's the dimensions? Air dry rule of thumb is 1" per year. Stack and sticker in a dry place. Get a moisture meter and check the MC.


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## MasterSplinter (Jan 12, 2013)

Oh man really. Its 2×12. Im using it for the top ofmy bench. Will that be a problem?


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## Dominick (May 2, 2011)

Your looking at least 2years. Depending on your conditions. Basements usually are damp.


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## MasterSplinter (Jan 12, 2013)

Its winter so basement is either cold or warm and dry. Will it cause a problem with my bench build? Therr is a thread on it. Affordable bench


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## Dominick (May 2, 2011)

Looks like you've already started working on it, so I guess it really doesn't matter at this point. Lol.


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## MasterSplinter (Jan 12, 2013)

Dominick said:


> Looks like you've already started working on it, so I guess it really doesn't matter at this point. Lol.


Lol. Well it does if as it dries it will twist the table. Will it shrink that much?


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## MasterSplinter (Jan 12, 2013)

Dominick said:


> Looks like you've already started working on it, so I guess it really doesn't matter at this point. Lol.


Lol. Well it does if as it dries it will twist the table. Will it shrink that much?


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## ACP (Jan 24, 2009)

I thinnk you'll find each piece is a little different. Do you have a mill with a kiln near you? You might check around and find how much it'll take to dry in a kiln. If you air dry I'd seal the ends and be patient. Doesn't help you much now for a bench, but I wouldn't make it with a wet top. Only disappointment can follow.


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## Dominick (May 2, 2011)

MasterSplinter said:


> Lol. Well it does if as it dries it will twist the table. Will it shrink that much?


You have it lag bolted. It will shrink in the width more than the length. You could elongate the holes to allow for movement. Or you can remove them and stack and sticker. They look like normal 2x12 that you get at a box store. If so you would be fine considering they are kiln dried.


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## scsmith42 (Jan 24, 2011)

MasterSplinter said:


> I am using a piece of rough cut pine. The saw mill said it was cut about a month ago. It is in my basement. How long for it to be dried? When can i plane it?


Wood dries based upon a blend of three environmental factors, and they are 1 – temperature, 2 – relative humidity, and 3 – air flow.
Drying rate is increased with (a) hotter temperatures, (b) lower RH%, and (c) faster air speeds. Temperature and RH% have a greater impact than air speed.

Each species of wood has a maximum safe daily drying rate, and this rate varies based upon three factors: 1 – the species of wood, 2 – the thickness of the wood, and 3 – the moisture content of the wood. The maximum safe daily drying rate can be safely increased as wood becomes progressively more dry.

In general, you can divide the drying process into three stages. These are 1 – from green down to 35% moisture content, 2- from 35% MC down to 25% MC, and 3 – from 25% MC down to final MC (typically 6% - 8% for indoor projects and 14% or so for outdoor projects or framing lumber).

Drying related degrade (damage) can be loosely divided into two categories – physical and aesthetic. 

Most drying-related physical damage to lumber occurs between the time that it is milled and when it reaches 35% MC. This is the most critical stage of drying, and during this time surface checking will occur if the wood is dried too quickly (checking does not occur when wood is dried too slowly) and internal checking (honeycomb) will occur if the drying speed is so excessive that surface hardening occurs. Often times, these checks don’t become visible to the naked eye until the wood has dried below 25%MC, even though they occurred when the wood was at a higher MC%. They key to preventing physical damage is to 1 – end seal the lumber and 2 – don’t dry it too quickly.

Most drying related aesthetic damage also occurs during the stage of green down to 35% MC, and this is usually due to being dried at too slow of a rate. One thing to keep in mind is that aesthetic damage (such as mold or other discoloration) usually requires a temperature between 70 - 100 degrees to occur; if the wood is kept less than 50 – 60 degrees, the potential for aesthetic damage is minimized. So, the key to minimizing aesthetic damage is to make sure that the wood is actually drying instead of being so moist that it is remaining static, and to keep it cool.

There is another minor impact, and that is that wood that is quartersawn takes about 20% longer to dry than flat sawn wood. 

One of the reasons that many experienced people who air dry like to harvest and mill their lumber in the fall and winter is because the cooler temperatures typically prevent the occurrence of aesthetic degrade, and by the time that summer arrives and the temperature rises, the wood has dried enough so that the surface MC% is below that required for the degrade to occur.

The ratio of safe drying rate based upon changes in board thickness is exponential. Drying rates are typically listed for 4/4 lumber, with 8/4 lumber having a safe drying rate being around .4 of the rate of 4/4.

Here are some maximum 4/4 [8/4 is in ()] daily drying rates for typical hardwood species:

Ash – white: 5% (2%)
Basswood – 12% (4.8%)
Beech – 5% (2%)
Birch - 5% (2%)
Cherry – 7% (2.8%)
Maple (soft) – 7% (2.8%)
Maple (hard) – 5% (2%)
Oak- Red upland – 3.8% (1.5%)
Oak – white upland – 2.5% (1%)
Oak – southern Red – 2% (.8%)
Sycamore – 3.8% (1.3%)
Walnut – 8% (3.2%)
Poplar – 15%. (6%)

*Most pine species can be safely dried at a rate of 12% - 15% per day for 4/4 lumber (5% - 6% per day for 8/4).*

Above we have the list of what the drying rates that you want to try to achieve, so how do you do that? The answer is by controlling the temperature, RH% and air flow to stay within a safe range for the species, thickness and MC% of your wood.

Here are three different environments that provide roughly the same safe drying rate (3% give or take) for a typical 4/4 oak board. This is a good rate to target from green down to 25%MC

55 degrees, 44% - 65% RH (or less)
75 degrees, 74% - 82% RH 
90 degrees, 85% RH
105 degrees, 93% RH

For 8/4 oak lumber, the numbers change significantly. Here are some good targeted numbers for green down to 25%MC

55 degrees, 76% - 88% RH
75 degrees, 91% RH 
90 degrees, 92% RH

Now, let’s talk about time. There is an “Old wives tale” amongst woodworkers that lumber requires “1 year per inch of thickness to air dry”. Knowledgeable professionals have been trying to “kill” this rule for a long time, as it simply is not accurate with today’s understanding of how and why wood dries, as well as equipment that is available to measure MC%. 

If you want to learn more about drying lumber, three of the most knowledgeable experts in the US regarding drying lumber are Eugene Wengert (Gene), Joe Denig, and Don Lewis. I've met all three and taken classes from Joe and Don. Their knowledge is formidable. There is a plethora of information available on the internet from them that a name search will turn up.

Having said that, one of the best places to start learning more about drying lumber is with the USDA Forest Products Laboratory manual that Gene and Joe wrote in 2000. Here is a link to it:

http://www.arconlab.com/handyman/woo...0Hardwoods.pdf


Another great resource is the older air drying manual from the USDA FPL, number FPL-GTR-117. This used to be available for downloading; now I think that you have to search further to find it. The manual that Gene and Joe wrote in 2000 is essentially an update of the -117 manual.

There is no one, single "correct" answer regarding air drying, as it depends upon the species, thickness, moisture content of the wood (which changes as it dries) and the external environment (temperature and RH%). As an example, in my portion of North Carolina you can successfully air dry just about any species of 8/4 lumber outdoors if you mill and start the process in the fall or winter. If you start air-drying 8/4 oak in the hot summer months though, you will probably have some surface checking. On the other hand, 8/4 pine and cypress will air dry just fine year round.

In my brother's home town of Phoenix, AZ, if you attempt to air dry 8/4 oak outdoors in the summer, you'll end up with a lot of firewood (and most likely in the winter too)!

Now that I've stated all of the above (mainly for the benefit of other woodworkers who are interested in drying hardwoods and might read this thread), *because of the forgiving nature of pine, basically you are not going to hurt it by drying it in your basement. * 

I would suggest that you stack and sticker the lumber, with some weight on top and a gentle fan blowing sideways through the stack. If you only have a few boards, lean them up against the wall at a gentle angle where air can flow around them. Turn them every couple of days so that they don't develop a bow in the boards. After 4 - 5 weeks the pine should be below 25% MC. Then, bring the lumber into a warm, climate controlled environment (such as your shop) and repeat the process for a couple of weeks. You should then be good to go on your workbench project.

Scott


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## MasterSplinter (Jan 12, 2013)

Scott that is some serious info. Thank you. How do you think it wil dry being bolted to the table.


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## MasterSplinter (Jan 12, 2013)

What should I seal the end with. Shoelace?


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## Dominick (May 2, 2011)

Wow!!!! I guess Scott broke it down and then some. Lol 
Nice job.


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## scsmith42 (Jan 24, 2011)

MasterSplinter said:


> Scott that is some serious info. Thank you. How do you think it wil dry being bolted to the table.


Personally I would dry it properly first, and then assemble. Pine is so forgiving that it's almost impossible to damage it.

Do you have a warm, dry shop where you can stack / sticker it with a gentle air flow across the boards?


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## scsmith42 (Jan 24, 2011)

MasterSplinter said:


> What should I seal the end with. Shoelace?


I prefer either anchor seal or Bailey's end sealer, but you can also use parafin wax. Some folks use latex paint, but it will allow some air loss so you'll need to plan on trimming a few inches off of the ends of the boards if you go that route.


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## MasterSplinter (Jan 12, 2013)

My work shop is in the basement. I will either have to make larger holes larger for adjustin later or make a different top.


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## Tennessee Tim (Dec 15, 2010)

Scsmith42,
I think I've read everything here......I may have missed a D/H in this basement???? This would help with the EXTRA moisture being added....BUT my question is....MY understanding of pine is (may be species type) is without high end heat to lock the sap it will always seep out????....THAT would be awful after spending so much time drying.... Can you, Daren or someone address this.

Thanks and have a Blessed and Prosperous day in Jesus's Awesome Love,
Tim


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## Brian T. (Dec 19, 2012)

I need to ask about the net neutrino bombardment and the rate of evaporation of dark matter. There are a bunch of practical woodworkers here, from rustic furniture to some of the finest wood flooring that you have ever seen.

Outdoors, under shelter and good air circulation, we expect a drying rate of approx (got that?) 1" thickness per year. Here at 53N in the magnificently mountainous Fraser River valley, that means that a 2" slab should be ready to work in a year. . . . bet on two years to be certain.

I'm waiting for birch. 1.25 - 1.5" thick. The vendor refuses to release any wood until "maybe" April. Will cost me $0.85/bf.

My carving wood is free and has been lying out in the weather up on mountainsides for maybe decades. All you gotta do is get up there and give it a kick = gravity will bring it down to the road!


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## scsmith42 (Jan 24, 2011)

Tennessee Tim said:


> Scsmith42,
> I think I've read everything here......I may have missed a D/H in this basement???? This would help with the EXTRA moisture being added....BUT my question is....MY understanding of pine is (may be species type) is without high end heat to lock the sap it will always seep out????....THAT would be awful after spending so much time drying.... Can you, Daren or someone address this.
> 
> Thanks and have a Blessed and Prosperous day in Jesus's Awesome Love,
> Tim


Tim,your understanding is correct and thank you for bringing up this point. What I've observed personally is that sap bleed tends to behave differently based upon when the tree was harvested. Winter harvested logs seem to bleed less sap over time than summer harvested.

Pine sap has a "memory", and it will crystalize at around 20 degrees cooler than the highest temperature that it has been exposed to. In the DH kiln drying process, at the end of the drying process we typically take a load of pine up to 160F to crystalize the sap. In a conventional kiln, sincepine is usually dried at 180F the extra step isn't necessary.

MasterSplinter, what you can do is to build a sterilization chamber in his shop to heat treat the load. It is very simple; if you send me a PM with your e-mail address I'll send you a copy of a article about a method that appeared in FWW a couple of years back.


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## DaveTTC (May 25, 2012)

Thanks for a thread worth remembering all.

Dave The Turning Cowboy


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## scsmith42 (Jan 24, 2011)

Robson Valley said:


> Outdoors, under shelter and good air circulation, we expect a drying rate of approx (got that?) 1" thickness per year.


I don't mean to be rude or offend; but the reality is that the drying rate will vary based upon species, thickness, and the temp and RH% exposure. Leaving wood excessively exposed to air drying results in degrade and material loss.

A disservice is being done to the original poster when he is advised that his pine boards will require "approximately" two years to air dry when the reality is that they will only require a couple of months or less.

Additionally, surface checking can and does occur if the wood is rewetted and redried throughout the drying process, and the longer that wood is air dried outdoors the more potential it has to be rewetted and damaged.

For a lot of hobbyists, if you buy wood green from the mill, dry it yourself, and lose 30% because of drying related degrade, it's no big deal because you still probably saved a lot of money on your lumber. But for a professional, every percent of degrade equates significant loss of revenue, and it is worthwhile to understand and manage the process.

Pine air dries about ten times faster than oak, it is not reasonable to expect that it would take "approximately" one year when the reality is that it will dry down to equilibrium moisture content in about 45 days in the summer or in a warm environment. 

4/4 Eastern Red Cedar will dry from green down to EMC (equilibrium moisture content) in approximately 30 days if started in the summer. The same lumber, if started in November, will take around 90 days due to the cooler weather.

30 and 45 days is a long way from being "approximately" one year...

Oak on the other hand, takes closer to the year that you mention. 4/4 black walnut will air dry down to EMC in around 6 months if some of them are summer months.

In your area in Canada, I concur that it takes longer to air dry lumber than it does in the southern US due to differences in the temp and RH% exposure.

Irrespective on location, the longer that lumber is unnecessarily air dried, the more likelihood that degrade will occur and also that it will become infected with insects.

A hundred years ago the "one year per inch rule" was the best that they had. At the same time, in medicine the best that they had was to "bleed" patients as a means of healing them. Fortunately, our understanding of lumber drying (as well as medicine) has vastly improved in the ensuing years, and today we can lose less lumber (as well as patients) by understanding and applying modern techniques and information.


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## Brian T. (Dec 19, 2012)

Well, let's suppose that you've scaled avalanche debris chutes in early summer, prime grizzly bear habitat, to cut and haul out 5 cords of diamond willow. Stripping the bark, the 2" stuff goes into the 2 yr shed. The 3+" goes into the 4 year shed.
a) if the next six weeks of early summer are cool and wet, the workign wood quality is wonderful.
b) if the next six weeks of early summer are hot and dry (your summer when the bark is too dang tight to pull anyway), you lose your entire investment due to cracking.
= = 
Sure, the 1" per side per year drying times can be argumentative. It worked OK a century ago. I'm positive that wood & trees haven't changed much in that time. Here, we really do have 4 seasons, like a lot of the northern temperate zone. Fora practical, down-to-earth estimation of air-drying times. .. . it works OK. The commercial mills still paint the ends of _ALL_ the wood. Which do you prefer? turquoise green or sky blue?

We have licensed tree prospectors for tone wood here. Martin, Yamaha and National have already come and gone in 2013.

Perhaps 3 key points are
#1 = don't cook your wood in a closed shed in hot summer.
#2 = don't keep your wood in the house where the humidity is so low that the increased drying rate is more likely to contribute to drying stress fractures.
#3 = paint the log ends with anything to aid in evening out the rates of moisture loss. NOT any guarantee but better than nothing (perhaps).


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## PSDkevin (Dec 18, 2010)

If it's just a pine 2x12 i would take my MM to the box store and buy one dried already. Use the other for a project down the road. That'll save you the temptation of using it before it's ready.


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## scsmith42 (Jan 24, 2011)

Robson Valley said:


> Perhaps 3 key points are
> #1 = don't cook your wood [lumber] in a closed shed in hot summer.
> #2 = don't keep your [green] wood [lumber] in the house where the humidity is so low that the increased drying rate is more likely to contribute to drying stress fractures.
> #3 = paint the log ends with anything to aid in evening out the rates of moisture loss. NOT any guarantee but better than nothing (perhaps).


<grin> Well summarized!

One clarification, my comments are with regard to milled lumber, not logs. The drying characteristics of logs are significantly different than lumber.


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