Cascading Firework Comet Mortar Rack
NOTE: This project uses PVC pipe. Skylighter does not condone the use of PVC pipe for firing any type of pyrotechnics. We suggest using cardboard tubes instead. In the materials list at the bottom of the project you'll find the 1/2" ID tubes we suggest.
Thanks to Geoffrey Kassin for this one.
"One summer, during the weekend following 4th Of July, some friends of mine who have a band were scheduled to play a private party. I furnished some flash pots, some small soup-can cremoras (fireballs), and about 80 Class C artillery shells. Everyone loved it.
Then at the Pyrotechnics Guild International convention in Fargo, North Dakota last August I saw the R.E.S. close-proximity display. WOW! I was inspired to try and figure out how I could do a similar show on a dime-store budget. I had about 400 1/2-inch diameter dragon egg (crackling) firework stars, about 300 3/4-inch emerald green to white flitter firework stars. The question was how could I fire them in precise, rapid succession? I do not have the money for 700 electric matches and thousands of feet of shooting wire; and I cannot get quick match. I lay awake in bed for many hours trying to think of a solution.
The solution for the tubing came quickly. I would use 1/2-inch and 3/4-inch I.D. schedule-40 PVC conduit (you could also use 1/2-inch ID cardboard tubes from Skylighter, a little safer than PVC). That solved the tube problem, but how was I going to fire them in precise, rapid succession? Friday night, I finally figured it out.
Saturday, I began building one short rack of 50 1/2-inch tubes. I went to Home Depot and bought two 12-foot lengths of 1/2-inch I.D., schedule 40 PVC conduits and one 12-foot long 1 x 3 maple board. (I chose maple, because it is hard, the surface is smooth and straight and I can get a good seal between two pieces of it.) I cut the PVC into 4-inch lengths. I cut the 1 x 3 in half into two 6-foot pieces. Next, I drilled a line of 47 13/16 diameter holes about 1.5 inches apart, all the way through one piece of 1 x 3. It’s important that all the holes be in a straight line. Using my Dremel tool and a sanding-drum bit. I slightly enlarged each hole enough so that I could glue each 4-inch length of PVC tightly into a hole. Once the glue dried, using the router base for my Dremel tool, and a slotting bit, I routed a slot 1/16-inch wide and 1/16-inch deep down the under side of the 1 x 3 mortar tubes base board. Now there was a 1/6-inch deep channel joining all the mortar tubes together. I then drilled a 1/4-inch diameter hole through the end of the 1 x 3 into the first mortar tube. I tightly screwed the blank 1 x 3 to the bottom of the mortar tube rack, so that the 1/16-inch channel was now completely enclosed.
Next, I loaded one gram of FG black powder into each of the mortar tubes, then dropped one dragon egg into each mortar tube on top of the powder. I then took the whole thing to a friend’s house that has a big front yard. I inserted an electric match into the 1/4-inch hole in the end of the board, all the way into the first mortar tube. I have a small electric firing system I made from radio shack parts. A length of visco fuse can also be used.
I hooked it up, pushed the button and 47 dragon eggs launched 30 feet into the air in about one second! It was beautiful. The fire traveling down the 1/6-inch channel from the black powder in the first mortar tube is enough to ignite the 2nd lift charge and so on.