plating, anodizing, & finishing Q&As since 1989
Painter ask if aluminum contains sulfur and mercury
I am a painter and work with sulfur and cinnabar. I am interested in finding out what the composition of aluminum is as I am painting on flat sheets of aluminum. Specifically, I am wondering if sulfur and mercury are components of aluminum? Any light to be shed on this matter would be greatly appreciated.
- Berkeley, California, USA
Lori, while aluminum is an element, the sheets you're painting are likely an alloy, or mixture of metallic elements. I'd guess you have 6061, or 3003, or maybe 1145. These are the most common, readily available sheet alloys in the States. Those numbers are just jargon for the designation system the Aluminum Association has come up with for the various aluminum alloys. E-Funda has a good general explanation of aluminum alloys, at http://www.efunda.com/materials/alloys/aluminum/aluminum.cfm. There you'll see that the common alloying elements are magnesium, copper, and zinc, and that wrought alloys are rarely less than 93% aluminum.
Sulfur is uncommon in aluminum alloys- it doesn't do anything useful and would merely exist as dirt. Mercury, however, is a definite no-no for aluminum structural parts as it can seep along the grain boundaries and severely embrittle the aluminum. That's the major reason you can't carry your flask of mercury aboard an airplane.
Yet unless you are painting the logo onto the tail of a 747, I see no reason why you couldn't coat your aluminum sheet with cinnebar. Have fun!
metallurgist - E. Aurora, New York