Assuming you are running 12 volts. If you damaged the horn I seriously doubt it was from using 12v for so short a time. As you saw a 6v horn is very loud on 12v and with short periods of usage should last longer than you do.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.