I have (2) auxiliary 50gal. aluminum fuel tanks on my boat. I would like to convert 1 of the tanks to Fresh water holding. The tanks can not be removed without removing either engine, and I would have to cut a hole to install a bladder, both of which are last resorts.Is there a chemical or solution that I can use to clean the tank?
I doubt it, but I'm primarily chiming in to support the dry ice suggestion. Before you create any sparks around fuel tanks, put dry ice in 'em. An exploding empty fuel tank can easily kill you. I suspect that you'll have to go with a bladder at the very least. Maybe you wanna hire a pro for this one.
If you do not get a direct answer from someone who knows the answer, maybe a boat builder conversant with all aspects of aluminium might be able to help. The one which springs to mind is Sea Otter Boats in Chesterfield, England - they are probably the experts in all things aluminium. They do have a web site.
No, aluminum has very large molecule and will absorb whatever you put in it, the bladder is your safest bet. To cut the tank, assuming it is diesel, you can put dry ice in the container to remove all oxygen. If it is gas, I would look for another place to put the bladder, for me, it is to great a risk even with dry ice.
