Fracturing Aluminum

We're making propellers over on the Chugger's Group. Right now guys
are mostly gluing-up the blanks that will become propellers. One of
the things that needs doing is creating the TEMPLATES that will be
needed in the final stages.

The templates are in the Files archive, full scale, so all we need to
print-out the templates then GLUE them to whatever we're using to make
our templates from.

Beer can stock will work. Ditto for shim brass, card stock and so
forth. Glue the pattern to the paper, cut it out with a scalpel. Or
glue it to the metal, SCORE the metal and flex the metal back & forth
until it breaks along the line of the score mark.

"Doesn't work," sez the Big Fella on the phone. He's been flexing his
templates for TWO DAYS and hasn't had one break yet. In doing so he's
convinced himself that the PROCESS is in error; that it's impossible
to cause beer-can stock to break along the score mark. And along
about there he pops the top on a cool one... which of course proves
he's wrong.

Soup cans. Sardines Bully beef... are all examples of having metal
FRACTURE along a SCORE MARK. Clearly then, the process DOES work.
Which means, when it DOESN'T the fault must lay somewhere OTHER THAN
in the basic principle.

(So... where? Probably in the flexing. I recall having some
problems with it when I first did it (using shim brass... beer came in
STEEL cans back then). The alloy used for shim stock is fairly soft
and takes longer to fatigue..)

-R.S.Hoover