Firewood drying experiment in the yard.

[jimbarry]

5 weeks ago we posted this info online about how much hardwood weighed for a specified volume of 32 cu ft. 

20230414 Hardwood weighs how much? - YouTube

It's now 5 weeks later and today we are checking in to see how much moisture has been lost with just natural air flow.

20230521 Firewood weight after 5 weeks - YouTube

[doc henderson]

nice study of your weight loss.  It would be interesting to weigh in and out of the kiln, and air-dry vs wet, and see what it costs to remove a pound of water.  

of course, air dry is free unless time really is money!  

[jimbarry]

nice study of your weight loss.  It would be interesting to weigh in and out of the kiln, and air-dry vs wet, and see what it costs to remove a pound of water.  

of course, air dry is free unless time really is money!  

Time is money when those that do not plan for the next year's wood. 
Our kiln costs about CAD$0.16 a pound to remove water from hardwood that is an avg 30% moisture content at the start and finishes at 20% MC at the end of the drying cycle.

[doc henderson]

sounds best to let the sun and air do all it can, in the time you have.

[Big_eddy]

Be really interesting if you would select a split from each crate, split it in half and check the moisture content as well. See how the moisture content changes over time. I would predict it drops quickly at first and then slows down, but I could be way off. As the wood develops more and more microsplits while it dries, it might actually start to dry even faster.

[bitternut]

Your post has given me the thought that I should take a sample piece of my recently split load of wood and check the outside and inside mc every week or so. Would be interesting to see how the drying progresses.

[Hilltop366]

Interesting, I wonder what the difference would be if the top was covered on one crate. Maybe next time.

[jmur1]

That's a great idea you have.  I always wanted to get some drying data on this stuff.  I would try to keep track of the daily humidity, breeze and temp.  You hit another important note about the spacing of the wood.  They say the ends are responsible for a significant portion of the drying.  Having a starting weight is perfect.  

I use one of those little handheld moisture meters and will spilt the wood then check the centers.  Usually I give some warning to people if its over 18%. Have you checked yours in this way?



jmur1  

[Stephen1]

How much weight do you loose kiln drying? 

[jimbarry]

Interesting, I wonder what the difference would be if the top was covered on one crate. Maybe next time.

We plan to conduct this test in the near future.

That's a great idea you have.  I always wanted to get some drying data on this stuff.  I would try to keep track of the daily humidity, breeze and temp.  You hit another important note about the spacing of the wood.  They say the ends are responsible for a significant portion of the drying.  Having a starting weight is perfect.  

I use one of those little handheld moisture meters and will spilt the wood then check the centers.  Usually I give some warning to people if its over 18%. Have you checked yours in this way?



jmur1  

The ends of the wood pieces are where most of the water evaporates from.  I occasionally split a piece and check with a hand held device. Even wood that's been sitting stacked in crates with good airflow for a year is typically around 30% MC. Typical results in our yard. To get the MC to 20% or less it requires indoor storage (after air drying outdoors for a year) for 3-6 months with good air flow, or, run i t through the kiln.

How much weight do you loose kiln drying?

2 cords on average takes out 200L of water when drying down wood from <>40% to 20%. 2.21LB in a litre of water.

[stavebuyer]

My experience building a double stack pallet did not work out for me. My work area at the time was shaded, so I didn't get the benefit of direct sun or wind. The inside ends rotted and sprouted mushrooms. What did work in those unfavorable drying conditions was cross stacking and maintaining a minimum of 3' spacing between the stacks. I also had several cords tightly stacked in single stacks. After 2 years and lots of mushrooms I had to restack all of it with space between the rows and cross stacked so there was space between pieces.

The relevance to your situation is that the tightly stacked pallets, while efficient for handling, are going to significantly increase the drying time. The wood is only going to be drying from one end.

Final size of the split, as well as the length of the split also influence the drying rate. You can take some freshly cut green rounds and split them into finely split kindling and it can be fully dry in matter of days. 

% of exposed surface area, volume of air flow across the surface, temperature, and humidity are all influencing factors.

I would be curious to know how much improvement in drying time would be achieved with a single row pallet?

[jimbarry]

I am sure a single row of pallets would improve drying time. Or even an extra foot or so of space between rows. But I don't have a football field sized space available, so there's that. 

Here's the update after 8 weeks total drying time.

20230622 Firewood scaled weight after 8 weeks - YouTube

[g_man]

This is good info. I split my wood in the spring and let it air dry in rows (mostly) for the summer before I put it in the wood shed. I never had any idea how much I was gaining or how long I needed to leave it out. Thanks for posting this.

gg

[Stephen1]

Great post. I have been using the metal totes for my firewood. I also use my sawmill slabs for firewood. I sort hardwood and softwood into racks 3x3 and trim to 8' lengths. I keep the hardwood and then cut and split and stack in the totes. 2 rows of wood in each tote. I thought about cross stacking but did not. Now reading Stavebuyer,  The next batch I will cross stack and compare. 

[barbender]

Jim, have you ever considered a single row pallet/rack? You have a mill so you could cut whatever stock you need to build them.

[stavebuyer]

Great post. I have been using the metal totes for my firewood. I also use my sawmill slabs for firewood. I sort hardwood and softwood into racks 3x3 and trim to 8' lengths. I keep the hardwood and then cut and split and stack in the totes. 2 rows of wood in each tote. I thought about cross stacking but did not. Now reading Stavebuyer,  The next batch I will cross stack and compare.

I found hardwood slabs especially hard to get dry. My theory is that the smooth band-sawn surfaces don't provide as much surface for drying as irregular shaped split round wood and drying time is more akin to thick stock lumber than firewood. 

[barbender]

I think the main problem is slabs lay together tighter in a pile.

[trapper]

I try to pile my slabs so no cut sides face each other after they are cut to length makes a bulkier pile but allows more air flow.

[jimbarry]

Jim, have you ever considered a single row pallet/rack? You have a mill so you could cut whatever stock you need to build them.

Early on we experimented with different sized crates; 1/2 cord, face cord, etc.


 


 
The 1/2 cord crates didn't work out for two reasons, too heavy and the middle row did not dry as well (obviously). The single row crates allowed for good drying but travelling over ground with a skidsteer was precarious. Traveling with two at a time was a little better but the crates were too tall, still tippy.
This was the first incarnation of the current design we use.


 
It quickly evolved into this design.



 

Hardwood end crates are generally 1/3 or 1/2 cord size. All the pieces dry well, whether covered or not.



 

Bulk kindling crates look like this.



 

One thing about the crates we currently use is that two fix into a 6ft6in box nicely.



 

We do not delivery though. It all gets dumped into the truck.

20230211 Firewood Kiln unloading for delivery - YouTube

The only different size crates we use for firewood is for 12" long pieces. Seen here on the left in the kiln.






The crates are easy enough to knock down for transport if a client wants to purchase.



 

Slabs storage 



 

 

[barbender]

You have a lot of R&D into those👍

[jimbarry]

Another thing when using crates that are 4ft wide and 3 ft tall, each row on the crate is the same number for its volume and its length. Examples; 16" long wood pieces stacked in a row 4x3ft is 16 cu ft. If the pieces are 14" long, the volume is 14 cu ft. 12" is 12 cu ft. You get the idea.

[fluidpowerpro]

Your skids are almost identical to what I use for my personal firewood needs. I first started with the tall, single row design and like you found, I switched because they were too tippy when moving with the fork on my skid steer. I then switched to shorter 3 row skids. I have not noticed any issues with the center row not drying but I don't doubt it's wetter. When I load the stove I probably get a mix of dry and not as dry, so everything still burns good. Right now I've got about 25 skids in rotation and I burn about 12- 14 per season so most have been drying about a year. 
The main reason I like using skids is it greatly reduces the number of touches for each piece of wood. If you think about how many times you handle the wood from start to burn, it can get out of hand if you don't do it smart. If the terrain allows, I'll pull my splitter into the woods as well as some crates, and it goes into the crates right there. 
Each fall, I then just use my skid steer and place the skids under a long 8' wide lean to I have on one side of my building. 
In summary, if you have the equipment to move them, skids are the way to go.

[stavebuyer]

I found bulk piles and handling with a grapple bucket to be the most efficient, but I wasn't selling KD and needing to load and unload a kiln either.

[jimbarry]

I found bulk piles and handling with a grapple bucket to be the most efficient, but I wasn't selling KD and needing to load and unload a kiln either.

If we weren't KD'ing, that's exactly what I'd be doing.

[DMcCoy]

Wow!  That's a lot of firewood and different pallet designs.  Thanks for taking the time to post the videos and information.