# Aluminum vs Stainless water tanks



## I33 (Mar 5, 2007)

I have stainless water tanks, 30 years old with broken baffles and beginning crevice corrosion. Repairing the broken baffles is going to run $600 per tank. That still leaves me with old thin-wall tanks with some evidence of corrosion and noticeable oil-canning issues. 

So, I am thinking about replacements. Custom rotomolded tanks are the most expensive--the molds are the biggest expense. Would sure be nice though. But I will not consider welded seam plastic tanks. Too many reports of split seams. 

New Stainless tanks are going to be above $4000. 

I would like to hear opinions on using 3/16" 5052 aluminum tanks for water. How much does the chlorine in municipal water accelerate corrosion in aluminum? What other "gotchas" do I need to be aware of?
Thanks,


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## Faster (Sep 13, 2005)

We had aluminum tanks in our previous boat, we owned it 12 years and it was 10 years old when we bought it... no significant issues. We did periodically muck the tanks out (some crusty white 'nodules' cropped up from time to time) but we never had any serious issues. AFAIK they are still going strong 5 years on.

Whatever way you go try to be sure to have good cleaning access to all baffled compartments!


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## mitiempo (Sep 19, 2008)

How many tanks? How large? $4000 seems expensive to me based on the stainless fuel tank I had custom made for $500. Possibly standard size rotomolded tanks will work.


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## wwilson (Jul 7, 2000)

I33 said:


> Custom rotomolded tanks are the most expensive--the molds are the biggest expense. Would sure be nice though. But I will not consider welded seam plastic tanks. Too many reports of split seams.
> 
> New Stainless tanks are going to be above $4000.


Gil,

I had a 40-Gallon ss tank with baffles custom welded in Annapolis in 2001 for $500. It is hard to believe that inflation has run that rampant since.

wrt your plastic tank idea. Sounds like you have done some homework. But have you checked out the non-custom Ronco marine tanks? They have a long list of seamless tanks for which someone else has paid the non-recurring cost. Here is a catalog .pdf link http://www.ronco-plastics.com/newRonco/images/MarineTanks_2010_.pdf
If you could adapt one or more of these to fit your space - it would save thousands and provide first rate water storage.


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## sailingdog (Mar 19, 2006)

I would recommend going with the Ronco tanks as well. 

As for the aluminum tanks, the white encrustations are aluminum corrosion byproducts from the tank being exposed to chlorinated water.


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## Waltthesalt (Sep 22, 2009)

I hunted around salvage places till I found a good used plastic than that fit. After cleaning it works fine. I had an aluminum fuel tank built. Need to be careful on mounting aluminum so there's no place where you can have eawater water up against the tank for a prolonged time. I sat the tank down poly strakes to avoid this.


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## mintcakekeith (Nov 5, 2009)

Not sure about aluminium for drinking water,isnt there some connection between aluminium cooking utensels and altsiemers ? or is it just me cant remember .K


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## timebandit (Sep 18, 2002)

What bunk!

When I was a airplane fixer upper in the early 60's they told us to be very worried about cuts and alum. poisoning and one other thing, something to do with fires and landing gears. I remember now, the seals in the strut were made from Teflon and when burned it produced a poisonous gas.

When wine makers start using plastic and alum. then I might think about it.



mintcakekeith said:


> Not sure about aluminium for drinking water,isnt there some connection between aluminium cooking utensels and altsiemers ? or is it just me cant remember .K


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## Shack (Sep 5, 2006)

*Aluminum Fresh Water Tank*

Faster & SailDog,
I am looking into an aluminum water tank, but I can't decide whether to paint the inside or leave it bare.

Corrosion (an little white globs) is the chief concern, but I think that using distilled water and maybe an annode in the tank might be sufficient to resist corrosion.

What do you think?

I don't want to drink bad water and then ...uke


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## ulferlingsson (Jun 10, 2010)

Anode protection of aluminium? Have you considered anodizing the tank instead? Might be a hazzle to get the cathode inside, but other than that, it should do the trick.


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## mitiempo (Sep 19, 2008)

I'd leave it bare inside. A water tank is a lot more likely to corrode from the outside in. Make sure you install it in such a way that it doesn't sit in water.


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## Shack (Sep 5, 2006)

*Anodizing?*

Ulfer,
That is an interesting suggestion. I would be working with an itegral tank and baffling. What would be involved with anodizing process for a tank like this? Should the parts be anodized during construction or is this something that could be done after construction?


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## Shack (Sep 5, 2006)

*Aluminum tank interior corrosion*



mitiempo said:


> I'd leave it bare inside. A water tank is a lot more likely to corrode from the outside in. Make sure you install it in such a way that it doesn't sit in water.


Mitiempo,
This is exactly my consideration. _Assessing the probability of corrosion inside the tank_. Many sources identify the small chlorine content from dockside water as a source of internal corrision. It may initially be a minor issue, but over time it might make a difference.

Currently my choices appear to be:
1) Risk small amounts of corrosion (in the long haul) 
2) Paint the interior then have it flake off over time ...presenting the happy task of trying to strip and recoat the inside of a tank. (PITA!)
3) Leave it bare and take measures to reduce or eliminate long term corrosion (anodes, distilled water supply, etc)

_By the way; some context here may help to answer the standard question "What's it worth to you." The vessel is to be used as a full time liveaboard._

Thanks!


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## mitiempo (Sep 19, 2008)

There are hundreds or thousands of aluminum water tanks in use. I doubt any have been coated inside. Anodizing would have to be done after construction, as would painting, as the welding would destroy the coating if it was done first.


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