I need some wiring advice. I have managed to survive
until now just using wire nuts for my home projects, but
I am at the point where it would be nice to use crimp connections
in a switch or outlet box, connecting 14 or 12 ga copper
wire.

Here's my question. When I go to Home Depot, all they
carry for crimp sleeves appear to be made out of copper
or some copper alloy. Anyway, these sleeves are pretty
soft. They deform pretty easily (too easily, I imagine),
and they fail my pull test. To top it off, the crimping tools
at HD are pretty cheesy.

My only experience crimping wire is non-electrical, but there
you use a "swaging tool" and a steel crimp sleeve. Once it's
set properly, it's almost as strong as the wire.

So far, I've just been staying away from electrical crimping,
as I don't want to burn the house down, but it would be very useful
to be able to do some safe crimp connections.

Any advice gratefully accepted.