I'm a dj by trade and also do balloons.

I do weddings also and I have seen a few times above the dancefloor a clear balloon stuffed with confetti and it pops on the first dance showering the floor with confetti.

Anybody know how these work?

Quick repost here lol.

Found these balloon detonator box things which uses a 9v battery turn a key and press button then a detonator cap pops the balloon.

Anyone had any experience with anything like this.

http://www.balloonaticasylum.com/index. ... -equipment

The Detonator works.... but you have to run cable, and recover the box (but if you are stopping on site - should not be a major problem, else you have to charge a deposit) the tried and tested method is a  "Pin Wand" less tech but guaranteed....... a  long "wand" with a fitted pin on the end..... for you or a trusted helper...to use at the right moment.

The Other alternative is the remote detonator, it is what I use (created myself) using squibs (same as the dets you describe) but again requires a deposit for the safe return.  

Most exploding balloons (18" or 3ft) are filled with small 5" balloons as well as confetti / flutter fetti (rice paper) since a lot of places have now banned confetti of any description...
 
for a link to see another view on exploding balloons (specially when you have not got the height)  https://www.youtube.com/watch?v=WEI6WD2W6wg

hope this helps a little.....