Rusty 71.2 steel tank

[jusgus]

A Dive Buddy recently gave me two steel 72's that he no longer uses, but the tanks have been sitting around empty for several years. Both tanks need hydro testing and one is clean as a whistle inside and the other is rusty enough that I need to tumble or whip it before the hydro test.
The last time I had this problem was in the 1980's when I found an early 1960's small steel Voit 1800 psi tank in a barn. The tank was completely rusty inside and had a 1/2" valve. Fortunately, I was able to borrowed a home made tumbler from a friend and the tank is still passing VIP's and Hydro's today. Since then I have lost touch with the tumbler, but I have been told that a whip will work.
The tank that I need to clean now has a 3/4" valve. Can anyone point me in the right direction as to buying, building or borrowing a whip or tumbler.

[swimjim]

http://s247.photobucket.com/user/Deepsi ... ry/Tumbler

Here are some build pictures of the tumbler I built using tread mill parts donated by Karl G of this forum. It has served me well. The wooden wheels I covered with bicycle innertube to grip the tanks. I found ceramic abrasive on the net fairly cheap and I've been able to remove the brown liners used in 72's from the 60's and 70's fairly effectively. You can probably source the tank cleaning and flash rust preventer through Bryan.

[jusgus]

SwimJim, Thanks for the pictures, I am impressed. I like the workmanship as a whole, but how in the world did you cut four round wooden rollers?

[pclarke1]

If I had to guess I would say they were made with a hole saw. http://www.mscdirect.com/product/detail ... 0=04256962 (I was just looking for a picture with this link, you can get them much cheaper).

[Bryan]

Rollers used on boat trailers will work as well. I have seen skateboard wheels used too. Takes a bit of torque to get two cylinders full of tumbling media rolling but not near as much to keep them rolling.

[swimjim]

Yep, I used a hole saw on the drill press. I had one that matched the dimension of the roller bar. That was something like two inches or so. For the outer, the biggest hole saw I have is a four inch, so that's what I used. The first time I did it was before I bought the drill press and I did those with a hand drill. The edges weren't quite square which caused the tanks to bounce a little. I lost a little efficiency in the process. It did work however. When I bought my drill press I redid those and my tanks roll nice and smooth now. Cut the four inch blanks first giving you a nice guide hole to work with, then cut the hole out of the doughnut with the smaller saw. Then slide them on applying a little wood glue where you want the roller to sit. Works pretty well. The motor from the tread mill turned out to be a 12 volt unit. The control board that came with it was probably why the treadmill was scrapped in the first place. No problem. I use my battery charger to run the thing. It turns over a tank at about 60 RPM. Just what the doctor ordered.

Jim

[jusgus]

Well thanks for those pictures, I am still wondering about a whip because that is NEW technology to me, and I would be obliged if anyone could enlighten me with information about the apparatus and the pros and cons of the process.