We blast the rust off before painting

Containers rust from the roof down

A storage container leaves the factory with a tough marine coating, and that coating holds up until something breaks it. A forklift tine or a falling limb dents the steel and cracks the paint. Water gets into the crack, and rust starts under the coating around it. On a box that has sat in one spot a long time, the worst of it is usually on the roof, where nobody looks.

Container roofs are thin corrugated steel, and after enough snow loads and foot traffic they sag in the middle. That low spot holds water. In central Illinois the puddle freezes and thaws over and over through the winter, then sits warm all through a humid summer. A roof that holds water rusts from the top down. By the time a stain shows on the ceiling inside, the steel up there is already thin.

The other place containers rust through is along the bottom. The lower side rails and the door sill sit closest to the ground, and they stay wet after every rain. A box set straight on dirt or grass never dries out underneath. The door end wears fast too. The locking bars and hinges get worked every time someone opens the box, and that rubs the paint off the steel around them.

• Every panel checked for rust before we quote
• Power wash to remove dirt and grease
• Rust blasted off down to clean steel
• Primer on before fresh rust can form
• Door gaskets and vents masked off

Container prep decides how long paint lasts

The work starts with a wash. Dirt and grease from the door gear have to come off first, or the blast just drives them into the steel. We power wash the outside and let it dry. Then we walk the whole box, roof included, and mark every rust spot. We also mark any place where the steel has gone thin or rusted through, because those need more than paint.

Next comes abrasive blasting. Rust has to come off down to clean, bright steel with a rough surface the primer can grip. Sanding or wire brushing leaves rust packed in the valleys of the corrugation, and paint over that rust fails fast. Freshly blasted steel can start to rust again in a few hours when the air is damp, so the primer goes on before that happens.

Holes and thin spots get repaired with new steel before any coating goes on, because paint will not seal a hole. After the primer, the finish coat goes over the whole box. For a hard wearing finish we use plural component spray, which mixes a two part coating right at the spray gun. If a step gets skipped, rust bleeds through at the seams within a season or two.

Condensation rusts a container from inside

A container is a steel box with almost no airflow, and steel changes temperature fast. On a cool night after a warm, humid day, the damp air inside turns to water on the cold ceiling and drips down. Around Fillmore that happens a lot in spring and fall. Over time the inside of the roof rusts as badly as the outside, and whatever you store in there gets wet.

If the ceiling inside shows rust, painting only the outside fixes half the problem. The inside walls and ceiling can be cleaned and coated too, with the wood floor covered and protected. Inside work goes slower because the space is tight and needs fresh air moving while the coating cures. It makes sense to do both in one visit, so the container is only out of use once.

Around Fillmore, containers mostly end up on farms and work lots, set beside a pole barn or a row of grain bins. A pole barn has a pitched steel roof, so rain runs off. A container roof is nearly flat and holds it. Setting the box on blocks at the four corners, on gravel instead of dirt, lets air move underneath and helps the new coating last.

Where the container sits changes the job

Marley Industrial Services works in a temperature controlled paint shop in Fillmore and out in the field. Coatings only cure right inside a certain range of temperature and humidity. When it is too cold, the paint stays soft. When it is too damp, it may not stick to the steel at all. In the shop we control those conditions, so the schedule does not depend on the forecast.

Plenty of containers are hard to move. Some are full, and some are tucked behind a building where a truck cannot reach. For those, we do the work on site. Field painting in Illinois comes down to picking the right days. We need dry weather, and the steel has to stay warm and free of dew until the coating has set. If rain moves in, we stop rather than coat wet steel.

Which way makes sense depends on the container and where it sits. An empty box that a truck can reach is often easier to bring into the shop. A full box, or one a farm uses every day, is usually better done in place. Either way, we look at the container first and give you a free estimate before any work starts. When you call, tell us the size of the box and how we get to it.