Quoth the Platinum Hammer of Durability's description...or, at least, something along those lines.
Use it once? Poof.
That is cruelly vague wording at its FINEST. I understand that the hammers are consumed, but you can use OTHER hammers on a particular object, but nowhere is that specified in the item's description. And even if I misread it or something, you don't say that above statement on what is actually a consumable item. That's just unfair.
So, I just blew my Platinum Hammer from the Hot Time event on a robe I'm planning on ditching in about a week. Weeeeee.