Painting SCUBA tanks

steel 72's???

First I would find some aluminum 80's or 40's for deoc/travel bottles. I have tried steel and find them way too heavy, even with drysuits and lots of underwear. We actually call them "ankle bangers" because of the odd way that they trim out underwater. Also make sure that they aren't the ones with the liners inside of them because they can't be 02 cleaned then.
Aluminum tanks are much easier to 02 clean because you don't have to add the anti-rust rinse after you have tumbled them.
My father-in-law has used autobody paint to cover up our old rental tanks he runs an autobady repair class at a local hioghschool and has access to all the toys. Some friends of mine just get autobody spray paint and cover them. Then, they repaint them every fall. Whatever process you use make sure that it is a cold process and don't use chemical strippers on aluminum tanks.
I just have the proper depth markings on mine, stickers from the boat store, and don't care what color the tanks are.

Just my experience.

Jon

How high can you pump your deco gas?
My 70' (50%) bottle is pumped to 3,000psi. That gives me more than enough gas to deco out if I loose my 02 bottle- I carry it in an aluminum 80. My 02 bottle was an 80 until this summer when I dumped all of my farce-fins on ebay. That gave me the money to buy an aluminum 40 AND kept me in helium for most of the summer. We cascade our 02 bottles to about 2,000psi. That gives me plenty of gas for my 20' stop.
I also belong to a a tech diving club called DEEPmidwest. We have members from Wisconsin, Ohio, Illinois and even Tennesse. Maybe you would want to start up the Minnesota contingant?
Many of them will be up there next weekend- I heard a rumor of over 25 people next weekend. They usually meet at the North end and there will be a trailer filled with mixing equipment there. My car has all of the freediving bumper stickers on it.
I was hoping to just freedive this time and skip the mixed stuff. Actually I really want to try out my new favorite sport, spearfishing, at Wazee next weekend. I can spend 6-8 hours in the water doing that, compared to the 20-25 minute bottom times we do on mix.

Jon