In the UK you can buy such things ready to fire, they're often called "flameburst generators". I believe they sometmes use a mixture of napthalene and BP to avoid the difficulties associated with inflammable liquids
I appreciate the advice guys... does anyone know what the amount of BP is to the amount of gasoline and how both are packed and set up in oder to fire? I was told one time that a BP b**b placed under a small bag of gasoline in a mortor and fired is the trick.... how much BP, how much gas, is it in a bag or not? size of mortor.
Thanks