Mini Kiln? Would it work?

[OlJarhead]

I am seriously considering this option with perhaps an added DH for the final stages.

Hard to say if it will work the way I want it to though because it will need to be at my offgrid cabin.

For not I'm going to put a dehumidifier in my garage and a fan and let them run 24x7 until I can get the wood moved but I injured my back the last couple times running a saw (and milling) and need to take it easier for a week or so!

Hoping the stacking (standing up) I did with a DH and fan will be enough to protect the slabs and I sprayed the blue stain that was forming when it was in the back of my truck (all of 48hrs) with a Fungicide in hopes of stopping it.

[doc henderson]

i have done a fair number of slabs under tarps and clear plastic, stacked and stickered on my drive, uncovering during nice breezy weather, and had box fans between the stacks.  i got a WM (walmart) accurite thermometer and humidity with a remote station for 28 buck.  will get it started and i got mine down to 9% MC.  look at timbergreen farms simple solar kiln.

[doc henderson]

http://www.timbergreenforestry.com/Simple%20Solar%20Cycle%20Lumber%20Dry%20Kilns%20at%20Timbergreen%20Farm.html

[longtime lurker]

I'm just going to share a story here, kinda relevant:

Quite a few years back I did a portable job for a friend. Deal was they put up the logs and I sawed what they needed which was a very long list, then sawed out a load (tractor trailer) for myself... plus I got meals accomodation, beer etc. All in all profitable but not ridiculously so which for mine is how business should be when you're dealing with friends.
So I set up the mill, run theirs through over about 10 days, then start on mine which I'm cutting for decking. Weather is dry& cold... heavy frost in the morning, quite windy all the time but dry wind so as I'm sawing mine its stripped out and put on the truck and I've got a sprinkler atop the trailer to stop it drying too fast. Takes 6 days to saw mine then I load the mill on top and leave, its about 2 hours to get onto the coast and then I hit rain and it rains all the way home which is about another 3 hours up the road. So this wood should be wet right? Fresh trees, wood stored under a sprinkler, then rain most of the way home it should be you'd think.
I stick a moisture meter in out of interest when I'm unloading.... cant believe the result, keep sticking it into boards all through the various packs.

15% MC.

Do not discount the effect of airflow, was the lesson I learnt. 150 miles more or less of hiway speeds in the rain is worth about two weeks in a kiln, and I didnt get much degrade either (stuff doesnt stain or rot, and checking & end splits is usually the major degrade in those species)

Just something to bear in mind when you're building a kiln, or trying to effectively dry wood without one.

[OlJarhead]

Simple Wood Drying Kiln - YouTube
This guy is clearly reading from his own script but he does make a very small kiln that looks like it could work rather well.  Not sure about the heat source for it, that might be the biggest problem, but otherwise, it looks like it would do for small batches.

Thoughts?  Ideas?

[doc henderson]

it will work, i think you could start outside and use clear plastic and no insulation.  open it up on clear sunny/windy days for a bit to air dry and wrap it to get to interior MC in the end.  the humidifier is several hundred dollars and at high moisture esp. with oak, the tanic acid will destroy the coil in a few years or so.  When i did a plastic wrap, i used two WM fans at 16 dollars each and a remote thermometer and hygrometer.  14 dollars on amazon.  I have a dehumidifier in my storage container, but that wood is already dry.  just to maintain.

[doc henderson]

maybe you have already stated, what kind of wood and what thickness?

[OlJarhead]

English walnut with 9/4 and 5/4 thicknesses.

I bought a $165 Dehumidifier and am willing to destroy it as long as it lasts a year or two ;)

I like the idea of doing the same thing outside.  My thoughts at the moment are:

1 -- stack and sticker in the driveway here where it is drier than at the property (and warmer) and cover with roofing material to keep the sun and rain off (not much rain really -- maybe 8inches a year).
2 -- when it gets down to around 16% either have built a small solar kiln at the property (hard to check though since I am not there often enough) or plan to build a small garage kiln.  All the stuff I have is under 8 feet (mostly 4 to 6 1/2 feet) so I could do an 8 foot by 4 foot super mini kiln. 

I won't be able to heat to 130+F in the garage without something like he did (heat lamps) though, whereas a solar kiln with the panel at 60 degrees would likely be able to hit that and then some (ideally, a solar kiln would have an adjustable panel that can tilt from 15 degrees above and below your latitude so it can be adjusted for winter and summer operation just like my ground mounted solar panels).

It will be a while before the wood is down around 16% though (probably faster here since it's such a dry climate but still, time will be needed).

[doc henderson]

i have air dried all my walnut out side with a cover and at 12% just moved into the heated and cooled shop.  retains color well.  walnut dries pretty easy and i am not sure the checking has much to do with how it has been handled so far.  at high MC air movement is important, and at lesser MC the lower humidity is more important.  the checks appear to be mid heart wood and maybe in line with the pith that was already destined to split.  @GeneWengert-WoodDoc .  the plastic cover can sort of take care of itself in terms of drying after you air dry.  looks like you are having fun, take care of your back!

[Ianab]

This guy is clearly reading from his own script but he does make a very small kiln that looks like it could work rather well.  Not sure about the heat source for it, that might be the biggest problem, but otherwise, it looks like it would do for small batches.

Thoughts?  Ideas?

The little DH unit will create some heat just as part of it's operation. You aren't trying for commercial kiln heat or drying rates, you just want a warm dry "inside" environment in the "kiln". If your shed isn't heated, then a couple of lamps on a thermostat would give enough extra heat to keep the DH in it's operating range. So for bringing "air dry" wood that's 10-20% already, down to 8% or so, it will work. At that level the wood isn't going to release a heap of corrosive tannins, which is what usually kills home DH units trying to dry green wood. 

Basically make the box as big as you want, then you can use it as wood storage, If you can keep the Humidity in the box around 45%, then any wood that's in there is going to settle to about 8% MC, and stay just that way.

[OlJarhead]

Having built a solar pop can heater and wanting to test it I happened to still have a small temperature logger that I decided to place in the garage this weekend while we were gone.  I wanted to compare the humidity of the garage with outside air readings as well as what the little DH was saying and I learned a few things:

1.  The reading on the DH is the humidity of it's exhaust air and NOT the rooms humidity.  While it read around46% which was close to outside readings the actual humidity in the garage ranged from a high of just under 74% to a low of 68% (the high was on Friday and the low on both Sunday and Monday).
2.  The garage remained a fairly steady 70F all weekend despite a wide range of temps outside which is consistent with higher humidity inside the garage.
3.  The humidity is dropping, albeit slowly, but I can see why some mention rust etc on things in their garages due to the high moisture content and chemicals coming out of the wood (tanins?)

I have my stickers now and just need to get the pile stacked and stickered etc so I hope to achieve that today if at all possible.  Then I'll order a moisture meter and start seeing how things go from there (outside).  This gives me my garage back, is what I am familiar with and I can then have lots of time to ponder the kiln ideas and decide what might be best for me but I'm thinking the garage mini kiln is likely what I'll do since it keeps it here, at home vs 160 miles north at the cabin ;)  I can then start working on tables once I get it down to 8%.

Might have to get some bug killer though just to be safe.

[doc henderson]

I am sure if the humidity has been high, then to begin with you are pulling moisture that has been at equilibrium form every porous item in your garage.  adding heat will drop it as well.  but sounds like you are working on the next plan that is better for you anyway.  Best Wishes.

[OlJarhead]

Thanks -- I have the lumber stacked and stickered finally.  Lots of end checking that is now worse than before despite the high humidity and of course it's in the upper 80's now and the humity is 21% so I expect I'll see some more rapid drying now but have the ends sealed and can hope the checks don't get too much worse!