If a terrific electric razor wasn’t enough to put you of shaving, I have another potential bathroom terror. Self-heating shaving preparation composition. Or self heating shaving cream to you and me.
This horror was invented by Ronald E Moses and Philip Lucas in the mid sixties. And the patent was assigned to Gillette Co LLC, because of course the evil empire of shaving would back this baffling idea.
Please note that the patent contain no drawing, nor any other illustration. So I had to search for public domain illustrations myself.
Now, the basic idea is sound enough; we all like to shave with warm lather. And while you and I and other sensible shaver would soak our brush in hot water, use a nice scuttle, and in general, y’know, be sensible about it… these two fellows had a different take on warm lather.
Well, warm shaving preparation composition.
Let us take a couple of steps back. Away from soap. Away from shaving cream. Away from common sense and sanity. And into the realm of exothermic chemistry. In short; self heating chemicals, applied directly to the skin.
These jokers came up with the idea of having a shaving preparation in two parts. One containing an oxidising agent, and the other containing a reducing agent. Or, as they would be called by rocket scientists; an oxidiser and a fuel. A hypergolic oxidiser and fuel, to be specific, since the reaction would start as soon as the two parts are mixed.
Or as the two guys put it in the patent text:
It has now been found that by providing a composition in two parts adapted to ‘be mixed with each other during or immediately before use, one part containing an oxidant and the other a reductant, sufficient heat is evolved by reaction of the ingredients to produce a sensible rise in the temperature of the mixture.From US patent 3,341,418
As an added bonus, most oxidizers are also corrosive. So a self-heating shaving preparation composition would be a kinder egg of things I wouldn’t want on my skin.
The two eggheads points out that some of the components used in shaving cream and other cosmetics – foaming agents, foam boosters, germicides, alcohols, acids, oils, and so on – are suitable as reductants. In other they oxidises in the right conditions. Or, to you and I, they can burn.
As for oxidizers, they are coming up with a long list of fun chemicals. Various peroxides, persulfates, and perborates. Chemicals that are familiar to anyone who have read the fantastic book Ignition! by John D Clark.
As a side note; if you haven’t read Ignition!, I strongly recommend it. It is freely available online.
In short, potentially terrifying stuff. And while they were talking of low concentration and controlled release of the heat… they also talked about placing the two parts of their self-heating shaving preparation composition in a two compartment pressurised aerosol container. Any leak between the two compartments would result in a runaway exothermic reaction. Which would result in increased pressure. Which would turn your can of self-heating canned goo into an improvised hot goo grenade. With a side order of sharp shrapnel.
So if rubbing corrosive chemicals on your skin in the morning wasn’t enough to put you off… you got a potential bomb on your bathroom vanity. Happy shaving!
You can read the full patent text over at Google Patents.