RP Propellant

Amount Wanted Print Recipe










Suitable Substitute


Use +1% boric acid

Individually grind all chemicals as fine as possible (except the aluminium), using a coffee grinder or mortar and pestle (the finer the powder is, the faster it will burn). Ball mill the potassium nitrate, charcoal and sulphur for at least two hours. Screen the aluminium into the meal using the screen method until the mixture is homogenous. The meal may be used as is, but it is preferable to moisten with a 25% solution of alcohol, knead and force through a 20 mesh screen to granulate it. This granulation procedure makes it much easier to work with while loading into cases and also makes is somewhat more powerful. To do this mix up a solution of about 75% water and 25% isopropyl alcohol (do not add any more than 25% alcohol). The alcohol makes the water wetter by breaking down the surface tension of the composition and allows the water to be absorbed easier. The drying time of a composition is also reduced as alcohol evaporates faster than water. Add some of the solution to the composition and mix well. Keep adding until it is damp enough to clump together if you squeezed an amount in your hand. Don’t make the mixture too wet or it will make granulating the composition impossible. If this happens, just add more dry mix. The spherical aluminium is not for effect, but it rather a phlegmatizer. It does produce an interesting tail effect, which is probably a glitter related reaction despite the fairly low sulphur content. It burns more rapidly compared to standard meal powder and is an effective rocket propellant, especially in smaller rockets.

Author: Alan Yates

Source: http://www.passfire.com/

© Fireworks Cookbook 2021