Navy T-34C's have a rubber bladder lining of the fuel tanks. They use jet fuel so it's not an issue of ethanol but more of a if there is a leak just replace the bladder solution.

Not sure about your fuel tank design but could you not use some sort of a liner?

Mark

On Aug 16, 2013, at 7:23 AM, Ernest Christley <echristley@att.net> wrote:

I think this is going to be the solution, Lynn.  The tank isn't exactly smooth at the outlet, so I'm going to have to make some modifications to the general concept, and I may end up with a bit of unusable fuel, which I don't have now.  But, I have a bulkhead fitting on hand, so I'll at least give it a try.


On 08/15/2013 12:41 PM, Lehanover@aol.com wrote:

If the tank is smooth on the inside. You could hand ream the hole out to big enough for a bulkhead fitting. The long run of the fitting would go into the tank. Make up a thick aluminum disc, big enough to cover the crack. Use fuel tank sealer in the hole and under the washer. Tighten the jamb huts with sealant under each.

You could have the same washer under the bottom side as well.

Now the crack is covered top and bottom with sealant and washers. Trim off any excess fitting and radius inlet to improve flow. The fitting can now be pointed in any direction.  I can make a drawing if you need one.

 

Lynn E. Hanover  

 

 

 

In a message dated 8/15/2013 10:30:37 A.M. Eastern Daylight Time, echristley@att.net writes:

The Delta has one ~50gal tank that sits behind the back seat.  Not
wishing to fight the compatibility issues between epoxies and whatever
the government may mandate be put into our fuel supply next year, I went
with an welded up aluminum tank which I epoxied into the turtleback.

For fittings, I welded in two NPT adapter bungs to the bottom of the
tank.  One for fuel supply, and one for return.   I had a small, seeping
leak at the supply fitting. I needed to turn the NPT-to-AN6 90 degree
adapter one more turn to make it seal.  I got it most of the way around
before I heard a sharp ping.  The bung that I welded in is now split. 
And that split is guaranteed to expand with vibration.

The only solution I can think if is to cut a round hole to remove the
bung, and then construct two plates (one for the inside of the tank and
one for the outside), with a hole in the center for the 90 degree
adapter.  The problem is, the tank can now be viewed as a bomb.  How can
I cut a hole in the bottom of the tank, which will require that I work
in an enclose space, without the possibility of a spark making short
work of everything?

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