Occasionally a vintage car project may require a custom gas tank. There are many ways to accomplish this, and even some companies that will build one to your specifications. But there are some craftsmen who would prefer to tackle a task like this on their own. This article will show one way to do this.
We will follow the process used by Don Houseman, a highly talented metalsmith who prefers using aluminum for his tanks. Aluminum has properties which make it ideal for tanks – it’s relatively lightweight, easy to form, and it will not rust. Also, many aluminum tanks are left in bare metal, and if they are well-crafted, they can become a focal detail point on the vehicle.
The vast majority of gas tanks are rectangular, which eases the fabrication and allows them to fit efficiently into most spaces. A rectangular tank has six sides – the front, back, top, and bottom, plus the left and right sides. While it’s possible to make a tank from six pieces of metal, it is far better to make the four largest parts from one piece of metal by making bends in three corners. A little time spent laying out and bending a blank for this style of construction will eliminate a great deal of welding, and make a stronger, better-looking tank.
Let’s watch Don as he builds the beautiful gas and oil tanks for his hand-built roadster. These tanks were made to fit closely behind the seats, but you can use these techniques to make a tank of virtually any size and shape, which could fit in any suitable space in a project vehicle. (Corresponding caption listed below each image)
The first step is measuring the space where the tanks will go and determining the desired shape and dimensions. These tanks will fit behind the seating area, matching the slope of the seat backs.
Next, a layout of the tank profile is made to determine the size of the blanks needed for the tank body and end caps, and the locations for the bends. Don is using .080-inch thick 3003 H-14 aluminum.
After the largest blank is cut to size, the edges are curled where the joint will be welded, by using Round-Over dies on a beading machine. This ensures all the corners on the tank will have a uniform radius, and it will reduce the distortion from welding.
Next, the bends are made on the tank body. Don is using a shop-made radius bender, which attaches to the edge of a workbench. Don buys his aluminum with a white PVC covering on one side to protect the finish and leaves it in place as long as possible.
This bender has a hinged apron similar to a commercial bending brake, which pushes the metal against a 2-inch diameter top die, forming a bend with a uniform radius.
With the final bend made you can see how well the edges of the tank line up. This tight fit-up is crucial when welding the seam.
Next, the seam is joined with a few tack welds, then worked lightly with a hammer and dolly to perfect the alignment, then tacks are made every 1-inch. Don is using a Miller Dynasty 350 TIG welder.
The baffles must be fabricated and fitted before the end caps are installed. Here Don is using Mittler Bros. Punch and Flare dies in an H-frame press to make holes in the baffles.
A sheet metal brake is used to form flanges on the edges of the baffles.
The baffles are checked to ensure they fit correctly.
Here Don is rolling parallel beads on each side of the baffles. These beads will reinforce the tank and reduce the chance of distortion when plug welding the baffles into place.
Here’s the tank with all the beads formed. The line of tape provides the ‘stopping points’ for the beads, ensuring uniformity.
In this photo, Don is drilling 3/8-inch holes for the plug welds that will hold the baffles into place. Pro tip – you can use sheet metal screws to hold the panels tightly together when making the plug welds, then remove the screws and weld the holes shut.
Looking inside, you can see the sturdy plug welds that hold the baffles in place. Don used 3/32-inch diameter 1000 alloy filler rod for all of the welding on the tanks.
Two bolt circles are needed on the top of the tank. This is the layout for the submerged fuel pump, and the fuel level sender is fitted on the other side.
Here the fuel pump is being fitted into place. The small rectangular box at the bottom isolates the pump from sloshing when the level gets low.
Once the baffles are welded into place, the edges of the tank can be curled with the Round-Over dies on the beading machine.
The dies work perfectly in the straight sections of the tank, but the corners will need a little tuning-up with a hammer and dolly.
The end caps are cut to size, the edges curled, and they are carefully fitted in preparation for welding.
Here Don is tack-welding the end caps into place.
Look at the nice, tight fit-up Don achieved. The better the fit, the better the weld.
Here’s the tank completely tack-welded together, with one of the vertical seams welded. Now you clearly see the benefits of getting a good fit-up on all the joints.
Don’s engine has a dry-sump oil system, so he made an oil tank in the same style as the gas tank.
Viewed from the front, you can see how well the tanks fit behind the seat in the roadster body, maximizing storage space in the trunk area.
Don devised a simple system of stainless straps to hold the tanks into place. Note the clean and accessible location of the filler tubes for both tanks. These tanks will be a focal point of his roadster whenever the trunk lid is open.
You can email your questions to Ron Covell, [email protected], or mail a letter to: Covell Creative Metalworking, 106 Airport Blvd. Suite 105, Freedom, CA 95019. You will receive a personal reply. Ron has many videos on YouTube, and full-length instructional videos can be streamed or downloaded from his website, www.covell.biz, along with a schedule of his nationwide workshops.