Aluminum water tanks.

Larry M said:

There is a good discussion on building tanks using epoxy in the book, "The Gougeon Brothers on Boat Construction", 5th Ed. They do not recommend West System for potable water or gasoline tanks. Diesel, sewage and gray water have held up well using West System epoxy though.

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While they are experts...they are not the final say....there have been integral water tanks in glass boats for years...epoxy is used to line many different types of tanks....

Don't know if it's their epoxy that shouldn't be used...there are lot's of formulations and the right ones are definitely needed for ethanol gasoline and biodiesel...but for water I don't see their logig is complete boats are built from the stuff...maybe it's just not economical at their epoxy prices...

Right from their site....

Builders have successfully constructed tanks for potable water, sewage, gray water, ballast and diesel fuel tanks and a limited number of gasoline tanks using WEST SYSTEM® epoxy since the early 1970's. The regulatory environment has evolved within the last thirty years and has placed safety restrictions on various aspects of tank building, specifically potable water and gasoline.


Regulations have made all of boat building more difficult and costly. If the correct epoxy is used...I'm pretty sure under normal temps and usage...it is more inert than the metal and equal to or more so than the polyethylene tanks.

It would take a really good reason to steer me away from a stock polyethylene water tank or tanks. No corrosion, no taste or health issues, and I suspect they are the least costly option.

For those with special needs or who just like to be different from everyone else, consider a bladder tank. Essentially a beavy duty rubber balloon that gets bigger when you add water and smaller as you use the water.

Once again I appreciate everyone's input. My research is showing that aluminum is perfectly acceptable for water tanks with the caution that care needs to be taken to make sure no chlorine gets in the tank. That will mean special filters for filling the tank IF we go that way. I really want some feedback from owners that have aluminum tanks and their experience. I'm not looking for recommendations for what material to use. Thanks, Chuck

Capn Chuck said:

I really want some feedback from owners that have aluminum tanks and their experience. I'm not looking for recommendations for what material to use. Thanks, Chuck

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From some of the posts I've seen (including mine), you have have been given exactly that. Albeit some posts from a second source.

iPad Forum Runner

Capn Chuck said:

Once again I appreciate everyone's input.

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as I said.

Capn Chuck said:

I really want some feedback from owners that have aluminum tanks and their experience.

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My guess is that the lack of response is because, despite the fact this forum represents but a tiny fraction of the boat owners out there, there are precious few boats with aluminum water tanks for the reasons that have been stated.

I suspect that if aluminum was truly a good material to build water tanks out of it would be the material of choice by many if not most boat manufacturers. It's cheap, it's light, and it's relatively easy to work with. Why make stainless tanks when aluminum is so much cheaper, lighter, and possibly easier to work with?

There must be a reason why you almost never see aluminum fresh water tanks, and if it's not high cost or difficulty of manufacturing or high weight, what it it?

Perhaps making a case for aluminum water tanks is like designing and building a house using the formula 2+2=5? There's a good reason you don't use it? I dunno..........

Greetings,
Aluminum water tanks......

SS tanks come back in weight due to the small thickness of the material used (compared to al) and the ease of welding a complete non porous weld plus the inherent strength.

Benn

Tidahapah said:

SS tanks come back in weight due to the small thickness of the material used (compared to al) and the ease of welding a complete non porous weld plus the inherent strength.

Benn

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I did not realize that for a given application like a tank SS is lighter than aluminum. Thanks for the correction.

Marin,
I'm not saying for a given size it is lighter but the weight difference is minimised due to the scantlings.
Cheers
Benn

I have two 120 gallon AL tanks the boat is 27 years old no problems.

Saying aluminum is like saying plastic.
There are many different aluminum alloys that are suitable for different applications and have different welding characteristics.
Some of the bi-metal alloys can/will have a galvanic reaction when submersed in water over a period of time. Some not so much.
There are 'marine grade' alloys that would be suitable and last a long time.
Others can debate the health issues.

I stated early in this thread that we have aluminum tanks. They are 26 years old and doing fine. We don't drink the water because the dissolved aluminum concentrations exceed National Drinking Water Standards for safe consumption. We choose to error on the side of caution. Read RT's highlighted article which he posted after my first post.

Should our tanks fail in the future, I will replace them with polyethylene or properly welded SS.

Page 118 in the September 2012 PM magazine has an article by Steve D'Antonio on this subject. He doesn't recommend Al due to galvanic, pitting and poutice corrosion. His first choices are SS and FRP. Love him or not, here is what he says as a wrap up:

"While aluminum is an ideal material for many boat building and marine applications, its reliability for potable and black water tank use is less than ideal."