Star Primes
From PyroGuide
Star primes are compositions that provide the activation energy necessary to light stars. Although some types of stars are known to ignite easily even without a prime e.g. black powder type compositions and chlorate compositions, it is a common commercial practice to prime stars no matter what they are made from.
Priming is good advice, since primes drastically reduce the chance of a star refusing to ignite or getting blown blind. On the other hand primes are sometimes used to form a protective barrier between two incompatible chemical compounds such as sulphur and chlorate. However, adaquately prime your stars and spare yourself the disappointment of getting through the trouble of making a shell and then have all your stars blown blind.
Note that some high temperature primes require ("outer") primes theirselves to be lit successfully.
Alongside common compositions (as listed below), many amateurs make use of other priming solutions that involve plain black powder combined with metal additives which make the resulting prime burn hotter. In this manner it is common to see e.g. 5% of finely devided silicon added to hand mixed BP, which will give a cheap but very reliable prime ensuring ignition in almost every case.
| Black Powder/ "Scratch mix" | Hardt #3 | Hardt #4 | Hardt #7 | Thermite | Red Thermite | Veline Superprime | Ofca Chlorate | Hardt #6 | Shimizu Igniter B | Shimizu Twinkler | |
| Potassium nitrate | 75 | 64 | 35 | 38 | |||||||
| Charcoal (airfloat) | 15 | 13 | 25 | 20 | 30 | 30 | 15 | 6 | |||
| Sulphur | 10 | 8.5 | 5 | ||||||||
| Potassium perchlorate | 35 | 55 | 65 | 37 | 74 | ||||||
| Silicon | 38 | 7 | |||||||||
| Meal D | 19 | ||||||||||
| Ferrotitanium -100 mesh | 9.5 | ||||||||||
| Aluminium (bright) | 45 | 3 | |||||||||
| Magnalium -200 mesh | 5 | ||||||||||
| Wood meal -70 mesh | 6 | ||||||||||
| Iron oxide (red) | 55 | 5 | |||||||||
| Lead tetraoxide | 80 | 22 | |||||||||
| Ferro-silicon | 20 | ||||||||||
| Potassium dichromate | 5 | 5 | |||||||||
| Sodium nitrate | 5 | 80 | |||||||||
| Red gum | 12 | ||||||||||
| Dextrin | 5 (add. %) | 5 | 5 | 5 | 5 (add. %) | 5 (add. %) | 4 | 5 | 4 | 5 (add. %) | 5 (add. %) |
Examples:
| Star composition | Inner Prime | Outer Prime |
| C6, C8, Tiger Tail, Willow | none, Black Powder | |
| D1 Glitter, Better Pearl, Winokur´s | Black Powder | |
| Perchlorate based color (Organic) | Black Powder | |
| Perchlorate based color (Metallic), Veline´s | Veline Superprime | (Black Powder) |
| Chlorate based | Hardt #4, Ofca chlorate | |
| Barium or strontium nitrate color | (Veline superprime) | Black Powder |
| Silver wave, high Al contents | Thermite, Red Thermite, Hardt #7 | Black Powder |
| Ammonium perchlorate based color | Hardt #6, Shimizu Igniter B | |
| Ammonium perchlorate or nitrate based strobe | Shimizu Twinkler |