How To Make Fireworks Rockets With Green and Red Tails

Thanks to Dave Stoddard for supplying this little article. These magnalium sky rockets are really quick to make using a rocket press; they're uncomplicated, yet very different than your average black powder sky rocket. Enjoy.

I have developed a couple of magnalium-based sky rocket pyrotechnic formulas over the past year that works well for sky rockets in the one pound to four-pound range. The benefit of magnalium-based sky rocket compositions is that they can be mixed, pressed, and flown in a matter of minutes. There is no potassium dichromate to mess with, and no drying time or extended prep time required for the sky rocket composition. This makes these sky rockets ideal for people to be able to build and fly on the same day.

First, some background -- Doc Steinberg and Doc Barr originally came up with a magnesium red sky rocket pyrotechnic formula that was published in the PGI bulletin in the late 1990's. The problem with the magnesium sky rockets was that it took too much time to prepare the sky rocket composition, and the use of potassium dichromate in the mix made it nasty to work with. I developed a magnalium pyrotechnic formula based on the original magnesium pyrotechnic formula, and Doc Steinberg worked with me to tune the choke, pressing forces, and other elements to get the sky rockets to perform well. If you build these sky rockets correctly, a four pound sky rocket will fly at least 1500 feet high, or more.

Doc Steinberg and I published the first pyrotechnic formula, for red magnalium chuffer sky rockets, in the December 2004 PGI journal. I have since gone on to develop formulas for green and yellow sky rockets as well. I flew four-pound versions of the red, green, and yellow sky rockets at the recent FPAG 4F event in November. Note that all of these sky rocket compositions are pressed on standard black powder sky rocket tooling using a choke (nozzle) that is as tall as the inside diameter of the tube is wide (on a tube that is 1-1/4 inch inside diameter, the choke would be 1-1/4" tall). The height of the choke is important as it makes the size of the exit smaller due to the taper of the spindle. The formula for red magnalium chuffer sky rockets is as follows:

Red Magnalium Chuffer Sky Rocket
Strontium Nitrate 55%
Magnalium, -325 mesh powder 28%
PVC powder 10%
Parlon 7%
Vaseline (dissolved in Naphtha) +2%

I grind the strontium nitrate in a coffee grinder to get it as fine as possible. DO NOT grind mixed ingredients! I have since discovered that the VM&P Naphtha is responsible for the chuffing effect, and allowing the naphtha to evaporate completely from the mix results in no chuff whatsoever. With good strong paper tubes, like the parallel tubes sold at Skylighter, you could probably omit the Vaseline all together. Do not use Vaseline if you are making this sky rocket composition for one pound (3/4 inch ID) sky rockets or smaller.

If you look at the oxygen percentage in the strontium nitrate (by molecular weight), you find that Sr(NO3)2 is 45.36 percent oxygen. I suspected we could make a green version of this pyrotechnic formula by substituting barium nitrate for strontium nitrate. Barium nitrate is 36.73 percent oxygen, so you need to increase the percentage of barium nitrate to get the same quantity of molecular oxygen as in the red pyrotechnic formula. We had the first successful flight of this pyrotechnic formula at a Crackerjacks shoot. Here is the pyrotechnic formula for the green magnalium sky rockets:

Green Magnalium Sky Rocket
Barium Nitrate 60%
Magnalium, -325 mesh powder 25%
PVC powder 9%
Parlon 6%

The barium nitrate is ground fine in a Wal-Mart coffee grinder before use. Note that there is no Vaseline in this formula. We omitted it, as barium nitrate is not as vigorous an oxidizer as strontium nitrate.

These four pound sky rockets fly perfectly. You could probably add 5% VM&P Naphtha if you wanted to get them to chuff (a nice effect), although I have not tried this for the green sky rockets yet.

Finally, if you look at the color spectrum, you will find that yellow is between red and green, based on angstrom wavelength of the emitted light. I estimated that a mixture of 60% green pyrotechnic formula and 40% red pyrotechnic formula would create a nice yellow magnalium sky rocket. I flew these at the FPAG 4F shoot in November 2005 with excellent success. In one particular flight, we estimated that one of the yellow sky rockets went over 2500 feet by counting the time between sky rocket heading brake and the time we actually heard the report (about 2.5 seconds). If you were to mix a yellow sky rocket composition without mixing the individual red and green sky rocket compositions, the pyrotechnic formula would look like this:

Yellow Magnalium Sky Rocket
Strontium Nitrate 22%
Barium Nitrate 36%
Magnalium, -325 mesh powder 26.2%
PVC powder 9.4%
Parlon 6.4%

With my rocket press, I have been using 2600 pounds of force to press these sky rockets. If you have a copy of the PGI article John and I published in December 2004, I provide a calculation for converting pressure to force based on the size of the ram in your press. You can use more force, but the additional compaction slows the burn rate somewhat. All of the chemicals and paper tubes that were used to make these sky rockets were purchased from Skylighter.

For four-pound sky rockets, we used sticks that were 1/2" square and 7 feet long. The sky rocket tooling we used was standard black powder sky rocket tooling (from Skylighter, Wolter or Harrison).

The choke (nozzle) is made from bentonite clay. I add 30% grog and 5% additional paraffin (Gulf Wax) dissolved in VM&P Naphtha. The percentages are very loose here. Some people use more fire clay; some do not use any. Mix the bentonite and fire clay together. Then melt the paraffin wax in the naphtha and mix the melted wax into the clay. Spread the clay out on newspaper and let the naphtha evaporate from the mix. It only takes 30 minutes for the naphtha to evaporate in 70 degree, sunny weather.

A few safety notes: Don't hammer these sky rocket compositions. They are equivalent to a form of flash powder. Wear cotton clothing and appropriate safety gear when mixing and pressing these. Don't make these sky rockets if you do not have a legal place to make them. It isn't worth the risk.

Dave Stoddard

Materials Needed
Read and review these Fireworks Safety Articles before starting any fireworks project.
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