Drying Cedar

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ednl

ed
Senior User
I have a question perhaps some of the sawyers or "driers" could help me with? I have a friend who has been air drying some eastern red cedar boards. He will bring them into an un-conditioned shop to acclimate for a month. If he uses it for indoor furniture should it be further kiln dried not just to bring down the moisture but to kill bugs? Does one even have to worry about bugs in cedar - whether used indoors or out? Isn't that one of the main attractions for using cedar in the first place - e.g. bugs ought not to attack it? Thanks for any insight you may have in this regard.

p.s. Just curious, if one who cuts up logs is called a sawyer, exactly what is someone called who kiln dries those cut up logs?
 
J

jeff...

My experiences with ERC is it pretty dry right off the stump and I have seen bugs in ERC but only carpenter bees and ants. Check it with a MM it's be ready to work for inside use when it's MC is 6~10%.

Thanks
 

Kyle

New User
Kyle Edwards
The only problem you may have with furniture is possible sap bleed through. If the pitch is not set it can flow under your finish marring it later.


just an fyi.
 

redhawknc1

New User
Wayne
Kyle, Jeff or any other sawyer....Would be great to add general information about proper procedures of air drying any species that we might buy from you that is wet (green)) so we want ruin it. Or point us in the direction of finding this info. I have a small supply of red oak and walnut and was wondering the appropriate way to air dry. Thanks for your consideration.
 
J

jeff...

Kyle, Jeff or any other sawyer....Would be great to add general information about proper procedures of air drying any species that we might buy from you that is wet (green)) so we want ruin it. Or point us in the direction of finding this info. I have a small supply of red oak and walnut and was wondering the appropriate way to air dry. Thanks for your consideration.

Wayne, there are many ways to air dry lumber but let me give it my best shot. Others please feel free to comment / correct what I'm about to write.

I'll use black walnut for an example... Only because it's one of the easier ones to dry...

1st is to know some characteristics of the lumber you want to air dry. Understand the max moisture content loss per day, it depends on the species and thickness. if you know the MMCLPD (max moisture content loss per day) for say 4/4 then 8/4 would be 1/2 of that 12/4 would be half of 8/4 again 12/4 would be 1/2 of 16/4. MMCLPD of 4/4 black walnut is right around 7%, so 8/4 would be around 3.5%, 12/4 would be around 1.75% and around 16/4 would be less than 1% (.875). If you exceed the MMCLPD, you can almost be assured there will be splitting and face checking. Because the wood is drying too fast.

2nd is to know if the wood your wanting to air dry is prone to bug infestation. Black Walnut (heart wood) is not - it's it's own natural insecticide. Black walnut is pretty toxic to bugs and humans. As a side note saw enough of it and you'll know what I mean :roll:. One of the big benefits to kiln drying is sterilization (bug kill) and pitch setting (soft wood) this is where the load of lumber is brought to a certain temperature and maintained for some amount of time. I don't know the exacts here (kiln dudes chime in please)

3rd is proper sticking, Sticking involves placing a row of lumber down and placing sticks (1" thick strips of wood) in between the rows spaced 12 ~ 16". Make sure you support the ends of the boards so have a row of sticks within a few inches of both ends. Here is an awesome example of some 8/4 BW that's sticked for air drying.
walnutstacked1.jpeg

Make sure you keep it up off the ground and provide a (roof) for your stack, an old piece of tin works great... just about anything would work aslong as you keep the direct sunlight and weather (rain) off the wood. Strapping the pile never hurts either it'll keep some pressure on the pile and help it dry straighter. Some people use weight (lots of weight) instead of straps. Position your stack north to south in a shady to semi shady area. Most wind blows from west to east and you definitely don't want to "cook" your lumber by stacking it in too much direct sun, doing so would exceed MMCLPD easily.

4th how long to reach equilibrium? Great question, all kinda depends on the weather, right now were cooling off some, I most defiantly would not sell green hardwood lumber in the middle of the summer, especially something like oak with a 4/4 MMCLPD of 3%. But I wouldn't hesitate to sell it this time of the year (later summer early fall). Why? because the chance to exceed MMCLPD is high also in the summer months it's ideal time for bug infestation and mold growth... But this time of the year is good, less chance to exceed MMCLPD, less chance of bugs and mold growth.

Overtime properly sticked lumber will reach equilibrium with the environment it's in. best one could ever hope to achieve outdoors is around 12~15% in North Carolina. When your stack gets to that magic number it's ready to be used for outdoor projects. this could take up to one year (depending on the weather).

5th What about lumber for indoor use? think back before air conditioners, dehumidifiers and forced air heat. ok I'm not that old but you get what I'm saying. We humans like our constant temp and humidity levels and we maintain it by machines. the interior of our home demands wood to be drier than it would be outdoors. Your target is 6~10%, 8% is ideal. so how do you get your stack down that low? three ways I know... Have it polished off in a kiln, dehumidify it yourself, stack it up in the living room for up to 6 months :). Once your lumber reaches 25% or below you can "beat" on it a little more... What I used to do before I met Scott was bring the stack into the shop, re-sticker it, make a trap tent along with a dehumidifier and run the dehumidifier till my stack reached 6~8% it took several weeks to suck the moisture out of the lumber. the tarp/dehumidifier method is good for a small amount of lumber maybe upwards of 100 BF, but is not practical for much more. If your shop is climate controlled then you can bring it into your shop , point some fans on it and let it accumulate to the environment it's in could take several months.

There's probably more I'm forgetting but this is the high-level executive answer...

BTW - it's much easier, far less hassle and quicker to buy kiln dried, of course it's gonna cost more...

Thanks
 

redhawknc1

New User
Wayne
Thanks so much for the explanation. Funny, the pic you added is currently my wallpaper on my computer. I saw that stack of walnut when I bought a bench from him. That is what got me to thinking about airdrying some for myself. Therefore the question...By the time I buy all the block and timbers, etc. and wait a year, am I assured that my stack would look as good as his? Very tempting to try at the prices of buying green wood from a sawyer versus kiln dried. Is it ok to have different species of wood in the stack as long as its stickered properly,separated, same species for stickers, etc? Guess I just would like a stash of a couple hundred board feet of a few domestic species for future work and trying to save a little money. Not sure this is the best way.
 

scsmith42

New User
Scott Smith
A couple of things to add...

The most degrade in drying lumber occurs when it is above 25% MC. Thus, the most critical drying time is from green down to 25%. Dry too fast, or too slow, and degrade results.

Once you're below 25%, you can safely increase the drying rate w/o worrying much about damaging the lumber.

Now the interesting thing is.... the defects caused drying from green to 25% will usually not show up until the lumber below 12% or so.

For home hobbiests, as Kyle has mentioned before storing your lumber in a warm areas - such as an attic - is a great way to take it from 16% down to 8%. Dr. Gene Wengert - who is one of the acknowledged experts re drying lumber, commonly keeps his own stock in his attic.

It's ok to mix different species in your air drying stacks. The things that are the most critical are your sticker spacing (I use 16" myself), the sticker size (1" is common for air drying) - my stickers are planed to 1" square, having your stickers all lined up on top of one another (very critical!), using DRY stickers - not green, and keeping sun / rain, etc off of your piles. Ideally, for air drying you would have your stack indoors in a dry area. Outdoor aternatives are to cover the piles (such as depicted in the photo), and use a shade screen type of material around the pile. The photo in Jeff's post also shows good sticker alignment from top to bottom.

One correction to Jeff's great post - the reduction rate for doubling the thickness is .4, not .5. Thus 4/4 oak which has a targeted daily MC% reduction rate 3% drops to 1.2% if it's 8/4.

If you want to learn more about drying lumber, the USDA has some great publications available. I have some on my computer, and am happy to e-mail them as attachments to anyone that would like them. They are quite large (and voluminous), and I'd recommend you only get the manuals that are applicable to you.

Regards,

Scott
 
J

jeff...

Wanye, Yes you can stack more than one species at a time and in the same stack. One thing I would suggest if you want to get started soon is to go with something easy to air like walnut for your first try. Poplar is also very easy to air dry, so is ERC, as is Pine and Cypress. One thing your going to have a problem with in pine, cypress and ERC is setting the pitch. I don't think poplar needs the pitch set, it's considered a hard wood.

Oak is a tough, so is sycamore, because it has a low MMCLPD, I would wait a few more months to buy that green for air drying.

What you want to do is slowly bring the MC down to 25% or less - green to 25% is the critical stage so don't try and dry it too fast or you'll risk degrade by defect. By drying in winter months, you don't need to be to concerned about bugs, mold and exceeding max moisture content loss per day. Draping landscape fabric over the stack will help slow down the drying, keep the water off the stack, most bugs out but still let some air through... Once summer rolls around you should be below 25% and then you can be a little more aggressive with it.

Just remember time is your friend when it comes to air drying lumber, don't try and dry it too fast in the wrong kind of weather.

Just as an example - I had a stack of oak waiting to be kiln dried, had it stickered like a good sawyer should. but it was the middle of summer. I covered the stack with a tarp during the day and uncovered it at night, believe it or not in those two weeks, I still lost almost 1/3 of the stack because it exceeded MMCLPD and checked. this is one reason I don't sell green hardwood lumber during the sumer months. I would hate to sell a load of hardwood lumber to one of ya'll only to find out it checked because it dried to fast. But now that the season is changing, I most surely will be selling green lumber again.

Thanks
 

redhawknc1

New User
Wayne
Found a lot of info on the USDA Forestry page http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr117.pdf
will need to reread a few times, but I,m starting to get a better understanding. Can get complicated. Thanks so much for the input. I think a lot of woodworkers would be interested in this info that you have provided. Think I'll start preparation for a site similar to the pic. Have a local sawyer sawing walnut next week, might give it a try!
 
J

jeff...

Found a lot of info on the USDA Forestry page http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr117.pdf
will need to reread a few times, but I,m starting to get a better understanding. Can get complicated. Thanks so much for the input. I think a lot of woodworkers would be interested in this info that you have provided. Think I'll start preparation for a site similar to the pic. Have a local sawyer sawing walnut next week, might give it a try!

That's great, give your local sawyer a try. BW is one that's pretty easy to air dry. I don't think you'll have much problem drying it, just try and remember not rush it. I'm glad I could lend a little insight, I usually confuse people - like I've said before I learned most of what I know by making mistakes. Mistakes are great teachers... So I can defiantly tell you what not to do :-D

I didn't noticed before but I see Scott has replied, he knows a ton more than me on this subject. You be in good hands now...

Thanks
 

Kyle

New User
Kyle Edwards
It looks like it has all been said here.

Drying your own from green really is the best method for walnut for the color. You will always have some wood in a through and through cut log that has defect, but even THAT is usable in some application.
 

redhawknc1

New User
Wayne
....so, would a utility building with good ventilation, not in the full sun, with minimum electricity for maybe fans for air circulation, and of course stickered properly be a good ideal if available to the woodworker? Learning about wood from stump to stock has been great! Thanks to each of you!
 

scsmith42

New User
Scott Smith
Wayne, re the utility building, I would consider putting the lumber inside it once it was below 25% MC in the summer, or anytime in the winter.

The biggest concern would be excessive heat/humidity inside during the summer - could cause degrade due to drying too quickly or being too moist between the stacks.

What you ought to consider is to build your own solar kiln. They are not much more complicated to build than a utility building, and a great way for a hobbiest to dry lumber.

Scott
 
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