aluminum water tank refurbish

[cwhofman]

with such a large bladder, how do you stabilize it?? seems like it would be a half full 60 gallon run away train?

Chris

[fnq grumpy]

Seems to be a secret that took me years to finally hear of but aluminium tanks with fresh water need magnesium anodes (as does all aluminium in any water). We had an aluminium water tank with more and more white corrosion product blocking outlet and pump screen but made of thick plate and not leaking. Fitted magnesium anodes as per hot water systems in Australia and no more white product.
If tank is not leaking, I would clean as well as you can, fit an anode system electrically connected to tank, anodes disappear fairly slowly, screen to collect any white lumps from tank and probably the end of the issue.
Never seen an aluminium water tank fitted with anodes or seen magnesium anodes in a chandlery, Australia or US. Common knowledge in other industries I eventually find out but a dark mystery in the boating world. Other than some aluminium boat owners, many of whom use zinc anodes anyway which are of little help to them.

[Frankly]

Can't imagine with the access you seem to have to not take a shot with epoxy. Water tank epoxy (usually steel tanks) is available and if you have any concerns put in a small poly tank for drinking. We did that years back (added poly tank) because of the concern of treating questionable water with chlorine (bad news for aluminum) and has worked out quite well.

I am looking at a 26 YO built in aluminum tank and trying to figure how to get inside when that day comes. Of note is how much the inside condition has improved since our long distance cruising is in the rear view mirror and we usually fill our tank with unchlorinated well water.

[Captain Puget]

Having gone through cutting out my aluminum diesel and water tanks last year (in pieces), I am not sure I would recommend this process .... a real pain.

If I had to do the over again, I would keep the existing leaky tanks in place and cut a hole in them to insert bladder tanks (keeping the tanks as a form to support the bladders. Cheaper, and the new bladders are easy to maintain, take out and clean, or replace as needed.

[papalagi]

My aluminum water tank is 30 years+ now, and it starts to show signs of corrosion. I bought me a big can of latex, the type used for sealing cisterns. ...and approved for drinking water of course. Latex products are also used to make water proof barriers in bathrooms, and the material got the properties needed. A rich layer, a little web for stabilizing, and another rich layer will do I hope. The aluminum tank will from then on, act as a support only.
I go for an other 30 years!

[geoleo]

My 30+ YO alum 2 -100 gallon watertanks were loaded with white alum oxide discs. Fortunately it had large access plates on top. We were able ro scrape and rub with 3M pads in almost all areas. Then we rolled and brushed 4 coats of food grade epoxy in almost all areas -tough job! Now just the 30 yo hot water heater with alum tank causes foul water ---however we do not drink hot water!