DO NOT PAY THAT SORT OF MONEY!!
Here is a basic guide for a gas/petrol blast:D
Gas fireballs are widely used in movie effects. They are quite simple to construct. It is simply petrol that sits on top of a BP charge or similar. Here is a simple example of this theory:
Step 1. Fuse (any sort of fuse that yo care to use) a film canister as shown in the diagram.
Step 2. Cut off a corner of a Ziploc bag or such like (cut enough as to make a pouch 3 inches deep). Then get a second film canister and place the bag corner in it. Fill the bag with 20ml of petrol.
Step 3. Fold up the top of the pouch and twist the bag closed. Take a wire tie and tie the baggie closed .
Step 4. Pour in 5g or more of Black Powder ( or what ever combustion that you can get your hands on) into the fused FC. Next insert the gas filled baggie and put the film canister lid on.
Light and take cover to test. Will produce a decent little fireball but is very flammable ina confined area. To cut down on the flammable part simply only use blckpowder in a larger dose and pack the rest of the FC with cotton wool.
Click here for a small pic
PIC
[Edited on 20-6-2003 by Grant]