How to Build a Chopper Gas Tank

A chopper embodies the American spirit more than any other machine. Built from a motorcycle frame and inspired by the imagination, just sitting on one can give you an idea of what it must have been like to create an entirely new nation. People love choppers and respect them more than any other bike, and the one thing that gives them the most character, aside from the monkey hangers and wheels, is the gas tank.

Instructions

1

Sketch out your envisioned design. Make a detailed drawing with exact measurements and follow it precisely right through the end of your project. Include the attachments for the tank to the frame (usually two in back and in the front), as well as the gas cap, and hole for the fuel tank shut off valve and fuel line. Review several tank designs, blueprints and styles to create yours.

2

Create a life sized cut out from poster board measured right on the frame of the bike, so you can see the shape and use this as a template to cut your steel.

3

Cut the metal pieces for the tank from this mock-up design. Use 12 gauge rolled steel or similar metal sheeting and a steel cutter to make each piece. Cut a piece for each side, the top and bottom, following your dimensions precisely.

4

Shape the curl of the side pieces by wrapping the steel around a large barrel, a roller, bucket or anything else that mimics the curve you are looking for.

5

Cut a form from wood in the exact shape of the bottom of the tank and the top, then line up the two side pieces on this form. Use braces or clamps to hold the steel to the form. Check to ensure the pieces fit.

6

Press the top end curl using a steel press or shaper; you can also try to bang this around a solid form with a metal hammer, just be sure the form you use is up to the task.

7

Round the edges further with a beading machine fitted with the correct dies to achieve the edge and shape you want your edges to have. Then tack weld the two sides together.

8

Cut the top of the tank and shape the curve in the same way, either use a hammer and form, beading device or metal shrinker to get the results you want. You can shape the top curve in the center by pounding out the steel over a form or mallet bag. Smooth out the bumps with a steel roller.

9

Tack weld the top to the tank. Then cut your hole for the gas cap, and check to ensure the hole is the right size by dry fitting the cap and gasket in place.

10

Smooth out the welds using a metal grinder, be careful to cut just the metal weld and inspect carefully for holes and a consistent weld bead along the entire seam.

11

Cut the bottom of the tank from the sheet metal and fit it to the tank. If it is flat, you will just have to cut the sheet metal, precisely and weld. If there is a curve in this section, repeat the steps mentioned above to create your curve. Then tack weld, and smooth out your bead with the grinder again.

12

Fit the bung for the petcock or fuel valve and attach the tank mounts, fitting them in place by positioning the tank on the frame itself.

13

Attach the tank to the frame and ensure that everything fits. Then make any final improvements to the gas tank; smooth out any bumps and grind down any weld beads that need attention.

14

Prime and paint your tank adding the graphics you want on your tank.