When to move wood to a Solar Kiln

[Matrixxdg]

Hi All,
I hope everyone is staying safe. I am a new sawmill owner, right at a year. I am finishing up my solar kiln build (8'x20' Virgina Tech) and have a few questions for everyone.

1. How long do I air dry my stickered lumber before I put it in the kiln?
2. Can I stack kiln dried lumber outside if it is covered or is that defeating the purpose?

Thanks everyone.

MG

[doc henderson]

welcome to the forum.  air drying will take hardwood down to about 12 % here.  the kiln can take it down to the needed 7% for indoor projects in an air conditioned space.  If the wood is above 32% then not much harm in air drying first.  The kiln is faster, so it depends on if you have several pallets of wood waiting for the kiln, then the wettest easiest to dry wood goes outside under cover.  Into the kiln when there is room.  After it is down to 7% MC, it can  be tightly sealed in plastic and outside, or into a conditioned space.  If the wood starts to line up waiting on the kiln, consider another kiln.

[Ianab]

How long wood takes to dry depends on "things". The species of wood, the season, the wind, the local humidity etc. White Oak takes a LOT longer to dry than Red Cedar for example. Moisture meter is your friend.

You can put green wood straight into a solar kiln, adjust the vents to suit, and that will be the safest and fastest way to get it dry.  But it ties up the kiln for maybe 6 weeks?  If you let it mostly air dry, so it's down to 12-15%, then move it to the kiln to finish, then you might finish the load in 2 weeks. Means you can move 3X the wood through the kiln. You might have 6 loads lined up air drying, and one finishing.

Once kiln dried it really needs to be kept sealed or climate controlled ot it will regain moisture from the air and drift up to that 12% level again. 

[Matrixxdg]

welcome to the forum.  air drying will take hardwood down to about 12 % here.  the kiln can take it down to the needed 7% for indoor projects in an air conditioned space.  If the wood is above 32% then not much harm in air drying first.  The kiln is faster, so it depends on if you have several pallets of wood waiting for the kiln, then the wettest easiest to dry wood goes outside under cover.  Into the kiln when there is room.  After it is down to 7% MC, it can  be tightly sealed in plastic and outside, or into a conditioned space.  If the wood starts to line up waiting on the kiln, consider another kiln.

Hi Doc and Ianab.... thanks for the quick response. Doc can you expound on "Wrap in Plastic"? Are  you talking about something like saran wrap or something similar. Shipping Plastic wrap. Also, can you stack and sticker a few slabs and then wrap them or do you have to wrap individually?


Thanks..MG

[doc henderson]

after they are dry, better to dead stack without stickers. then you are trying to seal out outside moisture, or as mentioned it will gradually go back up to 12 %.  I use a well sealed container with a dehumidifier in it.  it barely runs once the wood is down to 7%.  so heavy 6 mill plastic so the wind and sun do not degrade it and or tear it.  I would wrap it neatly like a prevent, and then you could stretch wrap it too.  I would band it and wrap it.  do you plan to sell wood, or save it up for yourself?  there are some other threads that talk about storing dried wood.

[GeneWengert-WoodDoc]

Maybe three wraps of Saran Wrap would be enough for a short (week) storage period.

In any case, all six sides of the pile must be covered, so maybe a 6 mil sheet on the bottom.

The longer you air dry in the open, the more degrade you get, including insects.  So, 20-25% MC is an ideal value for stopping air drying and going into the kiln of any type.  However, some wood, like hard maple, benefits from going into the kiln as soon as sawn.

[YellowHammer]

When wood comes out of a kiln, it should be at its optimum moisture content, bug free, mold free, the best condition it can get.  Unless you store it in a suitable, sealed environment, it will degrade.  

If you leave it outside, or in any uncontrolled environment, it will regain moisture, regain bugs and lose quality.

[terrifictimbersllc]

Also, if you dead stack  dried wood outside (stack without stickers), unless it is wrapped up completely, rain can get in between boards at places and then mold/fungi can grow there and stain the wood.  

Cant trust tarps for anything.  They leak moisture. So pretty much have to keep outside wood stickered.