How did they get the stripes in Stripe toothpaste?

Dear Cecil: Being typical college students, my friends and I were sitting in my room this Friday discussing our favorite childhood toothpaste brands. One of us recalled Stripe toothpaste, which was characterized by its incredibly straight red lines. We started joking about cans of polka dot paint and the like when it suddenly occurred to us that we had no idea how the lines came out so straight. Cecil, could you tell us how this seemingly impossible feat was accomplished? Tom G., Evanston, Illinois

Cecil replies:

There is little, it seems, that the mind of man can’t accomplish once it sets itself to a task. Striped toothpaste is only a beginning.

The stripes were created by a special device that was fitted to the nozzle end of the tube: a tube within the tube, if you will, about one inch in length and perforated with a ring of small holes around the top.

Toothpaste tubes are normally filled from the flat end, which is then folded over and sealed. In the case of Stripe, a red toothpaste was first filled around the special fitting; the white toothpaste, filled second, held the red toothpaste in place at the top of the tube.

When the tube was squeezed, the white toothpaste would run through the special inner tube, while the pressure of the squeeze simultaneously forced the red toothpaste through the tiny orifices at the end. With the flow of red matched to the flow of white, the toothpaste emerged from the nozzle perfectly striped.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.