shipping containers as kilns

westpalm · April 24, 2004, 06:29:17 PM

guys im looking some advice on drying lumber after i have it cut im looking into the future and am only kinda kickin ideas about,,,,
ok recently i got 3 off those 40ft steel shipping containers at good money ... well i pushed two together and took the burnin gear and took the middles out ,,, which gave me an inside area off 40ft l x 16ft w x 9ft6 h ..
being in south florida when the doors are closed the inside temp reaches around 110 deg during the day ...
thats the background ,,,and i guess the question is do i use dehumidifier vacumme pump or just close the doors and let it sit ,,
i know its a kinda general question ,,, but i was kinda hoping someone may have done this we a shipping container and have some advice
thanx lads
;D

DanG · April 24, 2004, 08:45:35 PM

Well, there's good news and bad news. The good news is, you came to the right place, 'cause some real bonafide experts hang out here. The bad news is, I ain't one of'em. I can tell ya a little, though. Forget the vacuum with that sort of chamber. It will collapse long before you pull enough vacuum to do any good. Also, you can't just shut it and forget it. It would get hot ok, but you gotta have some way to remove the moisture. That brings us to the third option you mentioned. Dehumidification would be your answer for a shipping container kiln. Your chamber may be a bit on the large side, though. How much lumber you plan on putting in it? Do you still have the 3rd container?

westpalm · April 25, 2004, 11:16:29 AM

thanx DanG ;D ,,, i was thinkin it was gonna be kinda big ,,, but i can always partition some off ,,, it was only a general question to see wot others think off the idea etc ,,, as for the 3rd container im using that as a workshop (read,, place to hide from herself when the chores needa doin ;D) was gonna cut one side out use material for a roof ,,build a lean to for mill when it comes ,,, as for volume of lumber ive no idea ,,,tho ive gathered up 45 large pine and around 7 big oak ,,,

Don_Lewis · April 27, 2004, 07:57:23 PM

Insulation is the problem. Spray foam would be the best way to go. Otherwise you will have a pile of rust in a few months. And there is no other kind of insulation that will work with steel shipping containers. That's why it always makes sense to buy refrigerated containers.

DanG · April 27, 2004, 09:07:28 PM

Don, I know about the corrosive properties of oak, but what about other species? Is this a problem with all hardwoods, or just oak?

Fla._Deadheader · April 28, 2004, 05:19:02 AM

  Been wondering the same thing as DanG. What about SYP and Cypress???

  Maybe part of the problem is, that all the sawdust that is left stuck to the mills and such, just hold the moisture until things start to deteriorate???

  Our mill turns black where bare metal is exposed and sawdust is left there for a while, and we just do Pine and Cypress.

Don_Lewis · April 28, 2004, 05:30:35 AM

Almost all woods give up acetic acid when drying. Oak is worse than others but it is a factor in all wood. When the air hits a surface that is cooler than the dewpoint, water condenses and corrosion starts. I have heard of containers rusting though in six months with people doing softwoods. Some people believe that tannic acid is the problem but tannic acid does not come out of wood during drying.

Fla._Deadheader · April 28, 2004, 05:46:34 AM

Very interesting. Thanks, Don.

westpalm · April 28, 2004, 08:19:15 AM

thanx guys ,,,sure does add new light ,, im glad i asked ,, didnt know about acid etc ,,,, u guys sure know ur stuff ;D

DanG · April 28, 2004, 09:15:06 AM

Thanks, Don. I've been looking for that info for a while. What metals, other than stainless steel, hold up well in that environment?

Fla._Deadheader · April 28, 2004, 09:34:51 AM

Propane Tanks, BIG Propane Tanks ;D ;D ;D

Don_Lewis · April 28, 2004, 04:12:08 PM

Aluminum is better than steel but not as good as stainless. But all metals stand up pretty well as long as they stay dry....no condensation.

DanG · April 28, 2004, 08:09:17 PM

Great info, Don! 8) Thanks! That's giving me some ideas. ;D

smwwoody · April 29, 2004, 10:54:29 PM

I have built a few kilns from sea containers. I Sprayfoam them real good then I spray mobile home roof coating over the spray foam. hang a fan line down the middle add some vents and finn tube hook it all up to a boiler and a kiln controller. and you are drying lumber.....

Woody

shopteacher · April 30, 2004, 04:06:09 AM

Don: What about coating the inside with epoxy? I see where they use it on metal where it's exposed to some pretty extreme conditions.

Don_Lewis · April 30, 2004, 04:58:42 AM

You could coat it but if the surface is allowed to have condensation on it, it will still corrode. Using spray foam in a container works well but in most places, you can buy a refrigerated container for less than the cost of a plain container plus insulation. Then you get a better surface inside and good insulation, especially of the floor. It is hard to get the floor done right with spray foam because it should be done from the bottom.

DeepForest · May 08, 2004, 10:16:44 AM

HI ... let me ask u one thing, what moisture prcentage r u looking foward to get. Im in florida to, and i think that now in summer u gonna be able to pull it over if u dont have high expectations.
I manufacture solid wood flooring, and drying its been a complicated issue always.

Don_Lewis · May 08, 2004, 01:32:22 PM

If you are selling it locally, 8-10% should be okay

Raccoonman · June 24, 2004, 12:10:20 AM

8)
Greetings Ya'll, I'm a newbie to the milling/drying end but It is something I've always wanted to do to extend my business one step closer to the tree.
I coated a container used for a solar kiln with pickup truck bed liner for a friend of mine almost 5 years ago. Not a sign of any corosion from the inside or out. The salt air creates surface rust on the outside to a degree but its easy to deal with. Its a fairly hard surface ( not the spongy one) and doesnt take a mark after a load has been drying on it for over 2 months. Its a setup that I am looking at also when I start drying.