Shipping connex vs reefer trailer

[bushhog920]

Wanting to build a kiln with nyle equipment and was wondering the pros and cons of a connex vs reefer. Seems like you can get an old reefer trailer ($1500-$3000) cheaper than a connex and it's already insulated. I will be drying mostly pine.

[Al_Smith]

A 40 foot shipping box,cargo ready can be landed for $2324 . Got one this summer .FWIW there must be a thousand people selling these things and some are "used car" sales people ,con artists ,flim flam men . I dealt with a lady in Texas ,box came from Columbus Ohio ,company office was near Cleveland  .No problem sat right where I wanted it .A coat of Rust-Oleum hunter green paint,no more Costco logo . Should last me the rest of my life .

[Mike W]

Reefer hands down at that price, even if you have to patch where and if the reefer unit was removed prior to sale.  insulated already and has a corrosion resistant wall panels for the interior (on most I've seen) and aluminum floor (most I've seen) with better seals.  I have a couple 40' connex containers on site we purchase just over 5 years ago ($2,500 each, delivered to our site) great units solid flooring and such, hotter then you can believe in the summer and just the opposite in winter, interior temp swings significantly during daylight and night time. If I was going to looking into cargo style drying units the reefer would be my first choice, just my $.02 worth as it were.

[YellowHammer]

A shipping container is made of Corten steel, it is designed to passivate in saltwater environments and is designed only for a 5 year corrosive environment service life.  

Kilns can be very corrosive environments, as the acidic vapor from the wood pretty much corrodes everything it touches.

A reefer is designed for refridgeration and does an excellent job as a kiln.

[Southside]

Just to add to this there is a significant difference between an over the road   reefer trailer and a container (conex) reefer.  The latter being a much better investment for a kiln as they have stainless walls and ceilings along with an aluminum floor. No plastic panels / liners to be found. 

[YellowHammer]

 

One of my kilns is a used connex reefer shipping container, high cube (more height is better) reefer and has stainless interior walls, aluminum outside, extruded aluminum floor, well insulated, and double door seal, insulated doors with cam locks. There is nothing to degrade and nothing to leak and nothing to rust.   I've been using it several years and it looks brand new, and if I'd built my kiln out of a basic painted shipping connex, it would be rusting out by now.

[DR Buck]

I bought two 20 ft insulated (reefer) conex containers out of Baltimore for ~$2800 each delivered to Northern VA.    Aluminum floors, foam insulated and heavy fiberglass lining inside.   Been using one of them for years as a kiln for my Nyle with no corrosion.
 

[scsmith42]

The only drawback to a reefer versus a steel container is that the foam insulation in the reefer "may" not be rated to high temps, such as 160F if you need to set the pitch in pine.

When I built my first kiln back in 2003, concerns about the foam insulation breakdown are what swayed my decision towards the steel.

However, foam standards may have changed since then, as Robert and others are not encountering problems with theirs.

[Al_Smith]

If I'm not mistaken the "Corten" steel is designed to get a surface rust which effectively blocks further oxidation of the metal .As such they should last almost forever .Which is not saying they would be a better choice than a reefer .Good option for storage though .
I've got lights and a fan inside of mine which is basically full of house hold items and so far no moisture problems because of moving the air around .

[Al_Smith]

A little info on these things .Most boxes are made in China at a cost of around 2400 bucks .The vast amounts of trade from China has left a glut of these things .The shipping giants have figured the cost of shipping these things back to China was costing them 8 or so percent of their profits and thus they sell them .
They claim they seal  so tight they can float about 2 months in the Pacific ocean if they fall off a container ship which they do every so often .I can't imagine how many cell phones would fit inside a 40 foot box,several thousand I'm sure .
Some have only made one trip and many less than 5 before they are resold .In reality they are nothing but a giant tin can .
What you have to watch if you want one is who you might be dealing with because there are some shady characters out there  .I had one joker claim he controlled every sale of these things in the USA ,like I was stupid enough to believe him .I tried to sell him a bridge in NYC after that nonsense .

[YellowHammer]

Yes, the Corten steel is designed to "passivate" and protect its surface by developing a rust coating over newly exposed steel.  However, the passivation doesn't stop continued oxidation, i.e. a coat of rust, on a metal intentionally design to rust, won't stop more rust, it only slows it down to attempt to extent its serivice life from rusting out in an expected one or two years to a design service life of five.  The passivation effect on steel is not nearly as effective as it is on aluminum.  As such it is a limited life design for sea use.  These containers are made with the most inexpensive of materials, and and such wouldn't be expected or designed to last a long time in a corrosive environment.  They are not designed for it.  

In actual kiln construction, these types of shipping containers sometimes don't even extend to their service life, especially if buying an already used one, and the guys at Nyle @K-Guy tell stories of these types of kiln pinholing and rusting out in a very short time, a year or two sometimes. In DH kiln use, the corrosive vapor is under slight pressure, and is actually driven into any cracks, seams, or compromised areas.  Pinholing was a problem with the ones we bought for service in my old job.  Over a period of years, the corners, seams, etc would look like someone had taken an awl to them and punched little holes into them.  Walk inside, close the door, and look for daylight.  Not a problem for us because we used them for storing heavy equipment, but a significant issue for a kiln. We first bought used ones, maybe a brand new one with lots of protective paint and such might work, (we did start buying brand new ones, with fresh paint and they were much better) but considering how much effort a kiln is to get into service, I wouldn't use anything that wouldn't last at least a decade.  In my case I don't see any degrade at all and expect at least 20 years from a true high cube reefer.    

The other benefit of an insulated shipping container is that they are lined with Aluminum or Stainless Steel and won't rust out in a few years. Nyle offers Container Kiln Packages.

[K-Guy]

From our experience at Nyle we only use insulated containers lined with aluminum or stainless steel. The first container used for our equipment were for pallet heat treating in the early 2000's and customers informed us that the floor fell out in 3-4 years. The tannic acid from the wood combined with the moisture gets under the wooden floor of a steel container and rots the supports under them. We would love it if we could offer our container kilns using steel containers, it would make them even more affordable. We don't for a reason.

[Al_Smith]

If for example you take a piece of bare unpainted steel and subject it to the elements where it's not in contact with the earth it might last a century .Look at the amounts of old horse drawn implements that are over 100 years old .Granted most were sold  as scrap decades ago but some are still usable .
With a box up on rail road ties with a good coat of paint should last a very long time .The floor for example is marine grade plywood and treated with bug repellent ,real thick also .The door seals are very robust ,About the only thing that would degrade them is the ultraviolet rays of the sun and with a coat of paint that should shield  them from same .All that plus each door has a double cam lock rod  ,tight .You have to make certain the box is level over the door way because if not you won't be able to operate the doors .Mine needs a little adjustment in that area .First though I need to make a fixture to hook the lift point and use a 12 ton hydraulic jack for that task .I broke a 6 ton "farm" jack that was made in the same  country where the box came from .Evidently that item was highly over rated which comes as no surprise .

[farmfromkansas]

I bought a reefer trailer box, 48', and it is all good except it is lined with fiberglass panels, which have a max temperature rating of 160 degrees, so have to be careful about overheating.  The solar panels so far have only been able to achieve about 120 inside the box, but did not get it working till September this year.  Hope to be able to get to 140 next year.

[bushhog920]

Thanks for all the info looks like the reefer is the better and cheaper option. Going to go back for a second look.

[K-Guy]

@bushhog920 

I warn customers to get the information off the manufacturers data plate and contact them. Ask these questions:
1) If it's insulated, to what R value (it can vary quite a bit)?
2) Is the floor insulated?
3) Can the lining and the insulation take temps up to 160°F? Remember these are made for cooling and some insulation that they use breaks down with higher temps.

If the floor isn't insulated, I recommend putting down 2" blue board rigid foam insulation and setting it on top of it. This gives a barrier from the ground sucking the heat out.

[rweiss1110]

I have a 18 foot container that I use as a dehumidifier with fans kiln. and I can dry about 400 bd/ft of oak in about 8 weeks. I just put a load of cherry  in there to winter. What do you think if I let the fans run throughout winter until it warms up, will it help to evaporate any moisture? Mind you I live up here where the temps get below 0 for 2 months.

 

[bushhog920]

 
 

 
 

well got a 40' reefer shipping container now. It's a 2017 model looks almost brand new reason it was taken out of service was it got bent in about a foot on the top front corner. All the other containers were 20 yrs old, rusty, and doors beat up and $800 more. Most important to me was the doors were in good shape and no rust .h  the hole in front is not a problem I plan to remove the a/c unit and build doors at that end and make it a continuous kiln setup. Next step is to get it set in place and give nyle the call they been waiting for. What an adventure it was getting it and me home. I have a plane and flew 2 hr Montgomery AL to Savannah GA to look at them. Found damage to the prop and couldn't fly back. Joked with the seller and said if I buy it now can you deliver today and I catch a ride home with the driver? Well 1 hr later it was loaded and I was on a 6 hr ride with a stranger and got to hear all about the times he want to jail and got shot.  Now that the prop is fixed got to figure out how to get back to Savannah and put the prop back on and and fly my baby home.

 

[Al_Smith]

The 40 footers are light enough they can haul them with a 1 ton pick-em- up .Some have tilt trailers ,some flat beds with rollers,goose neck  .I don't know how they dub them now,used to called "hot shot " .