I find the stripe-making mechanism in the toothpaste tube very interesting indeed (re this column). Mind you, I was the kid in Grade 3 who did a science fair project on toothpaste tubes.
What I want to add to Cecil’s wisdom is that Aquafresh, which has stripes that go all the way through the toothpaste (three colours, if I recall correctly), does not have a similar mechanism for keeping the stripes in order; the toothpaste is simply fired into the tube in pre-striped form. I know this because I once turned a full tube of Aquafresh into ordinary green toothpaste by squeezing the tube back and forth to mix the contents.
Cecil’s text does not indicate that there was a barrier between the red and white components of “Stripe”, although Slug’s illustration seems to show one.
John W. Kennedy, I think that’s an error on Slug’s part. The paste is viscous enough that a barrier would not be required to keep the two colours separate, and would only serve to waste the last inch of white toothpaste when the barrier blocks the holes.
jawdirk, I’d guess rifling would only serve to muddy the outer layer of toothpaste. There’d be a lot of friction preventing the paste from turning. But I’m not an expert in toothpaste dynamics, so there it is.
There are (apparently) two different types of striped toothpaste:
White with ‘painted’ stripes - these work exactly as Cecil describes.
And solid stripes - these are merely extruded from one big striped block in the tube, the viscosity of the paste and the absence of voids prevents them becoming too badly mixed (under normal circumstances, although if you determinedly do what stypticus did, you can get them to mix)
I dissected a tube once (I think it was Aquafresh) and there was no fancy mechanism in there, just a large blob with very broad stripes that narrow down as they are extruded through a funnel-like shoulder.
There was a question about this in GQ a short while ago, wherein I posted this crude diagram of what I found when I dissected the tube.
I’m using Colgate whitening, which has two components - a white paste and a green gel. Noninvasive inspection shows it appears to have the two layers up against each other with no separator, except at the nozzle, which has a divider between the two colors. This seems odd given that the two colors have a curvy swirl as the boundary. This is my first time with this brand, so I will find out later what happens as the tube gets used up - whether the two colors stay on separate sides of the divider or not, etc.
The thing I found interesting was how much Slug’s depiction of Cecil has changed from the article in question (linked above) with the current rendition.
CREST Dual Action Whitening is the former variety.
The blue gel stripes are definitely extruded from separate holes because they do not lie flat against the white but bulge out like the beads on red licorice vines.
Mangetout, I was hoping a staffer would answer. I think it is someone else. The very old columns are drawn in that style, which does not match the later style that most of us are familiar with that is Slug’s. Not a difinitive answer, because I don’t know for certain, and can’t cite the name of said previous artist.
