guys thanks so much for the advice. I am going to try and stay away from putting any holes into the brick. The building is not mine, and the owner said that I could hang a sign as long as I am willing to cause zero damage. I like the idea of the epoxy putty and putting the hook into that so that I could just chizzle that away whenever I am done...Are there anymore ideas that we might have overlooked?
Well I was almost gonna mention a 1/4" plastic shield and a screw on hook. And if it was just you afraid of damaging your own property, I, like some of the others here, might of tried to reassure you that that's pretty much industry standard, and not to worry about doing "damage".
But I see that you were told not to by the land lord not to. So yeah pretty much gonna have to go with the putty stuff, I have never used it but it looks good on the commercials.
How big is the sign? if not to big then 2 hooks, one at each of the top corners. if the sign is huge then you can put as many hooks as will fit in the width of the sign, that should hold it.
When you do go to "chizzle" them off, and there's any damage, just remind the land lord that he didn't want any holes in the wall.
It would be easier to fill a little 1/4" hole in the mortar joint than patching a spalled brick face. But that's only if that putty is so good that it actually requires a chisel to take it off, probably not though.
I suspect you'll be alright with the putty.
Good Luck. JB.