Looking for HSM article on coloring aluminum, or how do I use the HSM index?

[david a]

Can someone give me the name of that article that appeared in HSM several years ago about anodizing aluminum?
I looked in the posted index, and tried a search here. No luck.. I'm sure I can find it in the index if I knew the article title, or maybe someone could point me to an index arranged by subject?
I too am making modifying parts for a Sherline, I'd like to blacken the new stuff to match the original.
Thanks for your help,
David