Read the anodizing article, nice to add that to my repetoire of ways to get into trouble with a chemistry set (thermite was fun too!). I really liked this part:
This creates hydrogen (just like charging a battery) which is very flammable. This stuff burns at the speed of thought when ignited, so do be careful. (Read as Remember the Hindenburg?)
It reminded me of the official NASA rocket technician's SOP on dealing with invisible flames from hydrogen fires. Now that's scary! The book says to extend a straw broom into the area suspected to be an invisible hydrogen flame. If the broom burns, you're right! No, I am not making this up. Here's a marketing blurb for a gizmo to "see" the flame, also a picture of the old fashioned test.
http://www.techbriefs.com/spinoff/spinoff1997/ps1.html
Hot!