I've had this Maine 'buoy bell' wind chime for about eight years now. I really like it. It has the haunting melancholy sound of a bell buoy at sea being tossed by wind and waves. It is made of COR-TEN steel which is designed to rust on the surface to create a protective barrier against further rusting. It came painted black on the outside and was supposed to develop this rich rust patina naturally over time. Well, the unpainted inside did rust completely after about a year, but the outside only rusted slightly, near the bottom, even after exposure to the sun, rain, and snow of the northeast for eight years. I wanted it to have a nice rust patina that looked like it had been hanging on the eaves of a lobster shack, at the end of a pier, for many a year, being splashed and buffeted by nor'easters and sudden gales. Seeing it was taking so long, I decided to take things into my own hands and, ah, "help" mother nature along and accelerate the process. I searched the net and found mostly dangerous methods to induce rust on steel using highly caustic or acidic chemical solutions. However I finally did find a simple safe method, using on-hand household chemicals, buried deep within a thread on the subject at a metalworking forum. I got spectacular results which have not only withstood the wind and rain of the southwest but have actually improved with the help of mother nature. I like the results so much, and there is so little practical information on the subject that is accessible to the general public, I thought I'd share this simple method with the instructables community.
Judging by the number of posts on forums asking how to do this, I see I am not the only one who wants to actually promote, rather than prevent, rust on iron and steel objects. I found out the basic information for doing this at the very cool ArtMetal forum: http://www.artmetal.com/blog/bob_turan/2009/04/rust_promoter . I'm guessing that there are more than a few instructables members who have a similar desire to prematurely age some iron/steel artifact, so I encourage people to post pictures of their resuls in the comments and add tips on how they did it so we can all learn. This method is not set in stone. Posts about useful variations on the method are always welcome.