Glenn Ashmore wrote:
I am beginning to wonder if locally built aluminum tanks are a good
idea. Every shop around here is tooled up for 6061 but marine tanks
need to be 5000 series. I will have to supply my own 5086 and TIG
welding rod and the best price I can find is in New Orleans. $130 a
4x10 sheet plus about $100 shipping. Still, a lot better than $300 a
sheet in Atlanta but not as good as $65/sheet for 1018 mild steel locally.

If I go with aluminum I think I will have to machine my own fittings.
There are very few sources of 5000 series aluminum fittings and the
selection is limited. It will be fairly simple to mill and tap some
NPTF fittings from 1" round for welding onto the tank.

I would like to hear some discussion of mild steel vs aluminum. Total
cost of mild steel tanks is about half that of aluminum but weighs about
twice as much. In this case a pair of custom 40 gallon would cost $600
in aluminum with some effort on my part to get the alloy vs $320 for
mild steel and weigh 72 pounds vs 125 for steel. From what I hear, a
well painted and installed steel tank will last just as long as
aluminum. Longer if the aluminum is not properly installed.

Ron White wrote:

I had my aluminum gasoline tanks built by Ezell Industries one of the
three
marine tank builders in Perry Fl. I let them decide where the baffles
were
( a wise move) also they provided the tank fitting and valves which
some of
need to be al. rather than ss or brass. One thing to consider also is the
pickup tubes, they made these with nylon? tubing swaged onto the al
tank top
fittings. Some other people I talked to were not up to speed on the
issue of
not using metal pickup tubes as they are subject to vibration and
fatigue.
Wouldn't want the pickup to break!!! I was very happy with Ezell and the
good work they did.
Then Painting, which I did. This system is my standard and I use it on
any
alum. thing I make for boats.
1, clean with acid ectching solution ( like, Ditzler DX533)
2 prime with dupont Variprime 615S self etching primer.
3 finish with several coats of 2 part epoxy primer.
For exposed alum. things, add about three finish coats of a urethane
enhanced enamel like Limco 1234.
All of the products are availble from automotive distributers I think the
key is using the variprime as is bonds to aluminum like nothing else I
know
of..



Either aluminum or steel will probably outlast both you and me. I've
seen diesel tanks for equipment on trucks made from steel that have
never been painted that were over 30 years old. I'm thinking about
making mine out of steel, but I plan on some type of coating inside and
out, just not sure what brand yet. Weight is no problem for me with a
steel boat and no plans for racing, just cruising. I would think that
would be a major deciding factor for you. Can you stand the weight.
Cost is always a major deciding factor for me. I have to build on the
cheap. I would think you would have more resources available. Is $300
or $400 a deciding factor? What about a poly tank? I'm sure you've
priced those, about the same as aluminum, but they're ready built.

Good Luck,

Donald

--
I'm building a Steel Robert's 434. You can sneak a peek if you wish by
clicking on me link below.
http://bellsouthpwp.net/d/o/donrayp/
'USA, Home of the best
politicians money can buy'