Rules of Combustible Incense Composition
Here are some guidelines to follow when compounding combustible incense. These are for use with the Cone Incense Base #2 recipe above. If they aren't followed, the incense won't properly burn. There's less room for experimentation here than with noncombustible incenses.
First off, never use more than ten percent saltpeter. Ever!
Also, keep woods (such as sandalwood, wood aloe, cedar, juniper and pine) and gum resins (frankincense, myrrh, benzoin, copal) in the proper proportions: at least twice as much powdered wood as resins. If there's more resinous matter, the mixture won't burn.
Naturally, depending on the type of incense you're adding to the base, you may have to juggle some proportions accordingly. Simply ensure that frankincense and its kin never constitute more than one-third of the final mixture, and all should be well.
Though this hasn't covered all aspects of combustible incense making (that could be a book in itself), it should provide you with enough guidelines to make your own. Experiment, but keep these rules in mind.