I don't recall hot glue being mentioned as a masking tool before. Theoretically, it should work the same as rubber cement. I would recommend using low temp hot glue as the high temp kind could take your silver paint right along with it. One drawback may be controlling the size of the bead, and also the stringing effect is seems to have.
Like any new idea, test it on something other than your armor first and see how it turns off in the event it doesn't go as planned.