drying pine and fir for farm use

[paulwheaton]

I'm thinking of setting up a solar kiln just to heat the wood enough to kill bugs and set the pitch.  

So, I would air dry the wood for a few months and then give it a coupel of sunny summer days in the solar kiln.

The wood would be for all outdoor use.

Would this be an effective plan?

[Ga_Boy]

Paul,

You stated that you would air dry the material first.  If you air dry it down past the fiber saturation point; that's around 20% to 30% MC you reduce the risk of doing dammage in the kiln.  To minimize damage during the air drying phase there are steps you can take.

I would guess that sucess for this process is determined by what the material is used for.  It is not kiln dried material, but it is sterialized.  Not being dried to 8% range you could still have movement after the projects are completed.

If this is a risk you are willing to accept then give it a try and see what happens.  The worst case is you end up strange looking with fire wood.


Mark

[Brad_S.]

Paul,

Welcome to the forum!  8)  8)
My opinion is it would depend on what you mean by "farm use". If you mean board and bat siding, for example, then it would be over kill to set the pich. I have many buildings sided with AD lumber. Unless you're using a very sappy wood like spruce with pitch pockets, or plan on machining the wood before you use it, the pitch is no big deal.
If you don't already have any infestations, then there is no need to sterilize either. My undertanding of entomology is that critters living in a log before it is cut need moisture, (i.e. ants or pine beetles) and even air drying makes that environment inhospitable, so they leave/die. Sterilization is usually reserved for dry wood lovers like powder post beetles, and wood that will be used in indoor environments. Even then, after you sterilize, since you are using the wood outdoors, re-infestration is possible, and with some species, likely.
Lastly, to do either, you have to achieve and sustain a 160 degree temp for an extended time, and I don't think you can do that in a solar kiln without supplimental heat, in which case making an insulated chamber with a heater may be easier.
My two cents worth.  ;D  There are those who know much more about drying than me, so wait for someone to second this before adopting it as fact!

[DanG]

Welcome, Paulwheaton! That's exactly what I'm trying to do with my "horse trailer" kiln that is discussed in the "Solar Kiln" thread below.  I'm also going to use it as a learning tool, so that I can build a permanent kiln for hardwoods.

It is my understanding that pine is pretty much bulletproof in a kiln.  I know that one large mill near here, is putting it into a 240 degree kiln for 20 hours, straight off the saw.

I'm pretty sure that setting the pitch is important if you want to paint it, or the sap will just run out through the paint.

I think you're on the right track, but a couple of days might be just a bit optimistic.

[paulwheaton]

Ga_boy,

I'm planning on building a pig shelter, a dock, an outhouse, a firewood shed and other miscellanous farm projects.

"The worst case is you end up strange looking with fire wood."  How did you know what I looked like?  And how is heating my wood gonna change the way I look?   :D

Brad_S,

I have no spruce.  I have just fir and pine.  I do have a fallen cedar log that I might try to cut.  

I figure that the idea is to get the heat into the middle of the board.  I've heard several folks say that if your boards are two inches or less, it makes it much easier to get the heat in the middle.  Kinda like with a turkey, the longer you have the heat, the deeper the heat penetrates.

Maybe the first solution is to just not bother with it.  It sounds like I might be fine with just air drying.  And then,if I get ambitious some day, I could do something with solar by day and wood heat by night.

DanG,

This is the first I've heard of the painting thing.  Thanks!   I'm not planning on painting most of this, but I would like the option.  

240 degrees is mighty hot!  I think that's pretty well beyond solar!

[paulwheaton]

So the moral of the story sounds like:  I'm not going to gain much by running this wood through a kiln at this time.  Because of what I'm using it for, I might as well just air dry it.  Should the day come that I want to paint it, or use the wood for indoor projects, then I should look at drying it.  

Does that sound right?

[DanG]

Sound's about right, Paul.  For most of the projects you're listing, air drying sounds like overkill.  I'd just nail the stuff up green.
On the outhouse, you could reap an extra benefit by using green stuff. With the shrinkage, you will get cracks in the walls. Most of the outhouses I have been in could use the extra ventilation. ;D :D