Full disclosure: I've only watched the anime and I'm still working my way through the manga (current on volume 5-6 of the Viz 2 in 1 re-release) so I'm mainly looking at the anime here.
I know it's a common fanon thing to portray Akane as frequently using a comedy oversized mallet out of nowhere, but I'm curious to know how many times she's actually used it.
I know when I watched the anime series, I only counted two instances. Once was during a shared dream that everybody had due to Happosai, in which Akane malleted Ranma in the dream. The only other instance was a later episode which had Akane launching Happosai with a mallet for exactly the reason you think.