Cargo conaiiners and Cor-Ten steel

[old jupiter]

Q: Admin, why am I not able to edit and fix that title-bar?? Would you fix it for me (and then delete this line)? Embarrassing!!

So far as I have read and been told, cargo/shipping containers are customarily made of Cor-Ten A (or an equivalent ASTM weathering steel). By the Cor-Ten manufacturer's own description (U.S. Steel, now owned by Mittal), this alloy is not recommended for use in marine climates, yet this is where cargo containers spend most of their lives. It is further stated that painting Cor-Ten interferes with the formation of the protective oxide layer, yet cargo containers are customarily coated with an expensive rubbery paint. Finally, it is stated that any places on a Cor-Ten structure that collect and hold moisture and dirt tend to corrode faster than alternative steels.

This all seems to call for a bunch of "whys?"

I have a 45' "high-cube" container I'm using as shop-space. Works well for me, and I enjoy looking at all of the creativity others have applied to the use of containers as shop, business, and living structures. But my container has a number of deeply rusted places that I'll have to deal with this summer. Not just surface rust, but places where big layers and chunks are coming off. Yes, I have read up on the recommended wires and proceedures for Cor-Ten. I'm so old that the container and any repairs will surely outlast me by many years. Still, I have to wonder about the standard practices here, why this steel was chosen, and then mis-used, and if anything now can be done to improve on what's been done by the container makers.

Does anyone here regularly work with containers, or otherwise know about the issues? So far, most of what I've found by googling is by folks other than welding professionals.

Finally, I'm wondering whether mobile repair-patching and customizing of containers for private owners might be a good part-time gig for a semi-retired guy. I'd like to hear thoughts on this for those who do it. From observing photos posted by these owners, happy owners, of work done by fellas you could only describe as welder-wannabes, who not only weld real ugly but who seem to have no feel for structures and loading, it would seem that expectations in this niche are rather low.

[aametalmaster]

I would copy the orig post minus the title line and start another thread then delete the orig post. I can't even edit any of it...Bob

[USMCPOP]

How about this?

"It is possible to paint weather-resistant steel. The requirements of such a paint system do not differ from those required for normal grades of steel. One significant advantage that occurs when doing this (as is common in containerised storage) is that damage to the paint does not result in under-creep corrosion to the surrounding painted area."

http://www.residentialshippingcontainerprimer.com/CorTen

As I understand it, CorTen doesn't have much if any advantage over regular steel in a marine environment regarding corrosion. However, it is stronger than many run-of-the-mill steels, and so a lighter gauge can be used to save weight.

[old jupiter]

How about this?
"It is possible to paint weather-resistant steel. The requirements of such a paint system do not differ from those required for normal grades of steel. One significant advantage that occurs when doing this (as is common in containerised storage) is that damage to the paint does not result in under-creep corrosion to the surrounding painted area." .

Thanks, Pop, but I'd like them to see my examples of under-creep corrosion. And I have seen an advisory on another site that Cor-Ten is best left un-coated, though naturally I can't locate it at the moment. I had seen the site you linked, which does have some good info.

I think I might take Bob's suggestion tomorrow, and copy/paste this so I can clean up the title bar. Possibly then others won't take me as a clod, and will add their experiences.

(EDIT) Naw, to heck with it, if I delete my part the rest would remain hanging here.