Metal shipping containers are constructed from Steel, but typically a special kind of steel often referred to as “weathering steel” or COR-TEN. Metal Shipping Containers and Steel Strength Steel storage containers are renowned for their strength. In addition to the natural strength of the steel alloy being used, containers are constructed with their steel formed into a corrugated pattern. This corrugation creates additional strength (particularly vertically) and is the reason why cargo ships can stack them, fully-laden, several deep. Steel shipping containers are rugged, can take a lot of punishment, and are often exposed to extreme weather conditions on their journey.
“One-trip” Metal Shipping Containers
“One-trip” containers are metal shipping containers that have undergone only one single voyage (usually from Asia to the United States). In one sense they are used containers, but since metal containers are manufactured in Asia and have to get to the U.S. in order to be sold…well, they must be shipped, right? And while the shipping company is at it, what’s the harm in using them to contain other goods while they are going in that direction? In fact, this approach allows the ultimate cost of a “one-trip” shipping container to be defrayed for the purchaser, relative to what it would cost brand-new i.e. shipped totally empty. So in a sense, “One-trip” shipping containers are new, while in another they’re used. Either way, they represent a bargain in our opinion!
Steel’s Insulating Properties
Steel does not have great heat insulating properties; if you have goods that need a stable environment, then climate controlled storage bays in a self-storage facility may be a better option for you. However, steel can provide an effective windbreak and we often see steel shipping containers being used in applications such as little league hot dog stands, fit-for-purpose hunting shelters, and the like.
COR-TEN is U.S. Steel’s trademark for its brand of weathering steel. COR stands for “corrosion resistant”, while “TEN” stands for “tensile strength”. Sometimes it is referred to as CORTEN without the hyphen, or simply as a type of “Weathering steel”. What Metals are in these alloys? Metals usually contained in COR-TEN steel include Iron (of course!), chromium, copper, manganese, and nickel. Materials that are technically not metals but are elements of the alloy include carbon, silicon, sulfur, and phosphorus. Some versions of COR-TEN also include vanadium.
Steel Storage Containers and Rust
COR-TEN is a special type of steel which is designed to be durable and rust-resistant. Ironically, the way it gets its “weathering” property is by fighting fire with fire, so to speak…COR-TEN steel left uncoated develops a very thin patina of rust, which then protects the underlying steel from rusting further. COR-TEN’s weathering properties notwithstanding, it’s customary to paint steel shipping containers, to provide an additional layer of protection. If and when the paint fails, then COR-TEN’s natural properties will come into play, resulting in the anti-rusting patina.
Oil versus Water-Based Paints
The vast majority of metal shipping containers are manufactured in China. The Chinese government recently mandated that going forward, shipping containers are to be painted with water-soluble paints rather than oil-based (i.e. organic solvent-based) paints. This is expected to raise the general price of shipping containers by $150. Fortunately, there are high-quality water-soluble paints available (generally acrylic based), which perform similarly to oil-based paints in terms of durability. When refurbishing containers, Outback Storage now uses water-based paints.
The Importance of Maintaining the Metal Shipping Container’s Surface
Pits, scratches, and crevices can act as traps for water or dirt. For COR-TEN to develop its patina, it needs to undergo a regular cycle of being wet and drying; staying wet interferes with this cycle and can result in a surface without a protective patina layer. For this reason, Outback Storage Containers pays particular attention during our refurbishment process to grinding away any extant rust on the container prior to painting (leaving rust underneath paint could lead to further rusting). Our goal is for each container to have a smooth, rust-free surface prior to the painting process for maximum long-term protection.
Selecting a Metal Shipping Container
Key things to consider when selecting a metal shipping container include:
- Size/Volume – will it be adequate for your purposes?
- Exterior condition – are there significant dents, holes, or rust?
- Door condition – does the door open and shut freely and securely?
- Floor condition – is the floor rotting or in good shape?
- Appearance – is it painted to blend in with, or contrast against, the surrounding area?
- Delivery logistics – where will the truck offload it? Will there be room to turn around?
Outback Storage’s Metal Shipping Containers
Outback Storage takes detailed photographs of all of our inventory and makes them available for your perusal on our website. You can browse inventory ahead of time before making a decision – and avoid selecting any containers that are aesthetically displeasing. Take a look at our inventory here! Containers For Sale