Fire Dept. seeks advice on Aluminum Tank Corrosion

A. Bill, you have done well to get twenty years of service from your aluminum water tanks. If they are now developing leaks, here are two options to get tanks which do not leak. The first would be to cut the tops out of the old aluminum tanks, clean up the corrosion as best you can and then line the tanks with 1/2" polyethylene plastic on all six sides. You should be able to find a shop that can weld the seams of the polyethylene together. Where outlet or inlets are needed, install bulkhead type fitting through the polyethylene material before sealing on the plastic lid. Depending on the size and shape of the tanks, you may need to install cross braces to stiffen the aluminum structure and use flexible hose to make the connections to the bulkhead fittings.

The second option would be to fabricate new aluminum tanks duplicating the original design. Either of these two options should get you another 10 to 20 years of service from your equipment. Attempting to remove the oxidation and repair the leaks in the current tanks could prove difficult. Typically, the aluminum will oxidize over a wide area. Attempting to patch all the leaks or thin spots will result in fabricating a new tank.

A. Additional details may elicit some suggestions. Is the corrosion from the inside of the tank, the outside, or both? Is there significant corrosion at attachments to other metals (steel, brass)? Does the tank contain a manhole opening for working inside? Is the tank detachable from the truck? Can the manufacturer tell you the Al alloy? Have you gotten a replacement tank cost? A method I used on extensively rusted steel in a non-pressure application was sandblast, epoxy primer (allowed to cure), fiberglass both sides, and topcoat.

Many Thanks for the question and responses - they are helpful to me - I am a Firechief in the process of making a decision whether to spend the extra $ to go stainless steel of half the $ to buy a new aluminum tank for our water tanker...3000 gallons...any and all advice guidance would be much appreciated...Thanks again