Custom 18 gallon aluminum fuel tank

[kabacj]

Design goals:

18 gallons in one tank for vehicle weight balance and simplicity of installation
In tank fuel pump
Use fuel safe fill plate so I can switch out the tank later for a fuel cell and keep all of my plumbing
Sump system with trap door to drain the tank to the last drop

I started the process making cardboard models

Then I drew the cardboard models in google sketchup

These were not big enough only around 12 gallons and did not have room for the fill plate

I tried a few variations that would allow for filler and fuel sender using two locations

Didn't like that and it was still too small

Finally I had a design that fit with minor frame surgery, was big enough, and took the fill plate and looked nice. I find if it looks nice it often works well too. If it does not work well at least it looks nice. Ha!


Time to start making parts


First step was the top

I am using a fill plate designed to connect to an internal bladder. I wanted to use all the same hardware with my bladder less tank

To do this I needed to cut and weld in a ring to receive the fill plate bolts

First I cut the top plate out

I ended up using two pieces of 1/4 inch plate to make the ring because I had the smaller pieces laying around and I could make the ring with less waste.



I welded up the ring and welded it to the top plate. Drilled it and tapped the holes for 1/4 -28



Next I cut and bent the front sides and bottom

The tank has 15 flat facets but is made from 5 plates. Top , bottom , two sides and the front.

Boy was that a pain in the neck. The sides are like origami.

The cardboard flexes and is much more forgiving then the aluminum. I ended up with more facets then planned .

Finally I tacked it mostly together and ran out of argon.