[Keith Seymore]

I can't believe I haven't already posted this story:

I was talking with some guys here at work and the subject came around to the '63 Corvettes, specifically the ones with the RPO Z06 (40 gallon) fuel tanks.

The big fuel tank was one of the first applications of "blow molding" technology, where a bag of parrafin is dropped into a female mold and then air is used to press the plastic into shape (like a plastic milk jug). These tanks were made at Chevrolet Flint Manufacturing where my dad was working on the project.

The desire was to fill the entire cargo area with fuel so, in order to a make the die, the toolmakers attached the rear portion of a Corvette coupe to a "Keller" (a machine which duplicates shapes by tracing them, photo attached below) and used the actual body to make the die.

The next problem they encountered, though, is that the bag of parrafin would not "fill out"; that is, when they hit it with the air it just blew out the bottom of the bag and went "PPPPPPPPPPFFFFFFFFFFTTTTTTTT" (think of the sound a balloon makes when letting the air out).

They struggled with this issue until time was getting tight and the pressure increased to deliver a production run of parts. Dad was driving home one day, after his usual 10 or 12 hour shift, thinking about how to solve this problem. As he drove, he looked over at someone's front lawn and their sprinklers were running. Noticing the fan shaped pattern of the water, Dad thought "hmmmm"....

On the way into work that night he stopped by the hardware store and bought two little sprinkler heads. He went in that night, attached one of the heads to the air drop and POOF formed a perfect tank. He shot 10 or 12 more, set them over in the office to be inspected, removed the sprinkler head and put it in his locker. Then he went home and went to bed.

About the time he got to sleeping real good the phone rings. It's his boss: "SEYMORE, GET YOUR #$%^& IN HERE AND SHOW US HOW YOU MADE THESE FUEL TANKS OR BLAH BLAH BLAH etc. He got up, drove back into work, put the little sprinkler head back in the mold and shot several more tanks. They made the rest of the production run and you can see the results here, a production option that was available over the course of a couple years.

In the attached photo, the Keller machine is shown in the General Motors Area Research Center, where the first 300 Corvettes were produced in Flint, Michigan.

K