For those of you who noticed or participated in
this thread, it is no surprise that the time has come to create my full-custom firework for this year. Due to work scheduling, as well as the legal minutiae of sales dates, etc, I was unable to get the head-start I usually aim for, and so am scrambling to get the beast assembled before the deadline (July 4 evening, obviously). So, without furhter ado, let's get to the disclaimer!
The following photographs are for entertainment purposes only - the author makes no claims as to expertship, or any knowledge beyond anecdotal, with regards to the construction or operation of pyrotechnic devices, and makes no claims as to the safety of any procedure depicted or referred to in these posts. Any person who uses pyrotechnic or explosive devices does so at considerable risk to themselves and others. Any alteration or damage to such devices renders them inherently unsafe and such devices should be immediately destroyed, and under no circumstances should such devices be ignited. Always wear goggles.
The base materials -
I have found that the heavy cardboard tubes that Schluter transitions are shipped in makes a wonderful fireworks container. They are actually far thicker (1/4" wall) than the commercial fireworks tubes, and, being cardboard, greatly reduce the likelihood of shrapnel issues if they should fail. The smaller tube is similar, with a 1/8"-3/16" wall, and, again, cardboard. Never use plastic, kids.
The tubes have been cut down into their final lengths. As well, I have shortened a commercial mortar tube, and got my package of fuse opened. We shortened the tube for both aesthetic and safety reasons - keep the center of gravity low, because you don't want this thing going horizontal if the wind gusts between stages 2 and 3. The star whistle will not be used in the final construction, and, for scale purposes, those hands belong to a 3-year-old. The final construct will feature more yellow tubes (6 or 7) in the first phase, but I ran out, and will have to grab another when I go to work.
A detail of the bottom of the mortar tube. The grey substance is silicone-based plumber's putty - another discovery I made during a prior build. It is non-flammable, non-toxic, and plenty dense to keep from getting blown out of a tube by a launch etc. plus, it's got just enough tack to cling to the inside of cardboard without additional persuasion.
The end of the construction preparation phase - the tubes have been drilled and labelled for the fuse run. The white circle is a light cardboard spacer ring for the top of the mortar tube, to keep it nicely upright during setup and transport.
Bottom details of the tubes - at the end of construction, the bottom of the device will be nothing but putty and cardboard, but the mortar tube goes inside the schluter tube, and I still need to be able to get into it from the bottom for now.
.6 ft/sec yellow visco fuse. I really wish we had an extra week or so so I could play around with the timing on this thing, but we work with what we have.
Final construction mockup - the firing plan is:
Stage 1 - Yellow tubes, will go off in sequence around the circuference, with each firing a roman candle ball and small spark shower.
Stage 2 - Schluter tube (in reality only the space between the inner wall of that tube and the outer wall of the mortar tube - shower of crackling sparks
Stage 3 - mortar tube - one airburst mortar shot.
Now that I think about it, I might want the mortar shot to fire before the shower of sparks - There may be a possibility of the spark shower damaging the mortar tube, which is no bueno. Hmmm.
Anyway, that ends my work for today. Tomorrow, I am hoping to be able to complete construction - finish the cardboard build and fuse run. If time permits, I may go ahead and load the charges tomorrow night as well, but we will have to see. Stay tuned!
