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A comp based on a hypothetical composition posted by Mike Swisher in the following thread: Mike Swisher Posted 5/12/2009 2:55 PM (#69707 – in reply to #69667) Subject: Re: Swisher Sweets (Blue) Member The characteristics of the fuel are “proper” only with respect to the oxidizer. Shellac is a good fuel with chlorates but does not burn well with potassium perchlorate, for example. On the other hand, sulphur is almost too good a fuel with potassium chlorate; it gave good results and was much favored in the nineteenth century, but it makes a mixture too sensitive for the ordinary handling stars experience in a firework factory. Sulphur appears to work well with potassium perchlorate in this particular composition and its desirable properties appear not to be outweighed by excessive sensitivity. However, to be on the safe side, I’d advise treating stars of this composition with the same respect one would handle chlorate/resin stars. I think their sensitivity to friction and shock is no worse, though I have not carried out objective tests. You can’t just substitute sulphur weight-for-weight for red gum. Red gum has more than twice the oxygen demand per unit of weight than does sulphur. In other words, for every ounce of red gum you remove you will have to add more than two ounces of sulphur, to maintain an equal oxygen balance. I looked in Frey’s book for a red perchlorate/sulphur composition, and oddly enough red is one color for which he gives no perchlorate formulae. Many times the nineteenth century texts suggest a way to go, but in this case that isn’t so. I haven’t tried it, but why not just replace the copper oxychloride in the blue star with strontium carbonate? Or try a purple, mixing (let’s say) 2/3 strontium carbonate and 1/3 copper oxychloride, in place of all copper oxychloride? The formula for blue calls for 12% oxychloride, so the suggested proportion would be 8% SrCO3 and 4% Cu oxychloride. It is by making experiments like this that you’ll discover your own favored compositions and in the process will learn how to adjust in mixing to do what you want to do.
