How can i make a basic firecracker into a waterproof firecracker?

I need to be able to use these fireworks (equivalent of m80's ) for a film sequence and they need to be lit above water and go bang down below. any help would be appreciated. thanks in advance.

caarntedd6 years ago
I've seen fuses used to ignite small detonators that in turn set off sticks of high explosive (ICI Powergel). The fuse cord was coated with a shiny yellow finish which may or may not be waterproof, but under this coating was a layer of a bitumen like substance which melted as the fuse burned.

The explosives handler told me that this was to maintain a waterproof seal while the fuse burned. The bitumous layer was waterproof. One end of the fuse is crimped into the det. and inserted into the explosive. The other end melts as it burns and keeps the fuse sealed, keeping water out.

So if you can coat the fuse with something similar to this maybe it will burn under water. 
Re-design6 years ago
Dip them in lacquer and let dry. The fuses may be a problem but give them a try that way.