Rocket Attack

Today we're building a small rack for multiple (sixty) mini single-shot mortars called "Sky Rocket With Report". A moment after ignition this item answers with a small caliber pop at mid-height (50-60'). They cost twenty cents each. On its' own, it is not very exciting. But based on last year's experiment, multiples all at once can provide an interesting interlude between longer lasting effects.

Once again the item diameter is measured. 0.41 is about 7/16.

Wanting to allow reasonable space between each tube to run the visco (½"), and depending on the config (4 x 15, 5 x 12, 6 x 10, etc) a corresponding-sized block of wood is required. Even numbers are more desirable to make the visco run economical - i.e. one visco fuse delivering ignition to two items at once, instead of one. I decide on 6 x 10, and find a block that is 7" by 15" in the scrap heap. Equidistant intervals are then marked (in this case every 13/16").

A grid is drawn lining up with the 13/16" marks. Given the 6 x 10 layout, it is decided that the length will face the audience, and the effect will be fanned perpendicular as a result. Mounting angles will be 2, 7, 12, 17 and 22 degrees in both directions. These angles are marked on the grid lines.

The drill press plate is angled to accommodate the desired angles. The drill press has a built-in angle gauge but it is not very fine, an angle finder is used for tuning.

Holes are drilled, stopping short of going through the block using the limiter on the drill press. The block is turned around to drill the same angle in the other direction.

All sixty holes are drilled on the grid, at the desired angles. The act/sequence number is written on the rack to ensure proper firing order in the show.

"Sky Rocket with Report" is unpacked. The plastic points used to help submerge the tube in soil (and make the 'live' end more obvious to the user) are removed easily.

Quick fuse visco is cut to estimated length needed. Zip ties are pre-pulled to make fastening easier. The first two tubes are inserted into the drilled cavities and fastened, starting a pattern that will continue until completion - each tube's ignition fuse running in the same direction as the linking visco. This provides greater contact in the off chance a portion of either fuse does not spit fire / ignite.

Drilling the holes the same size as the diameter of the tubes makes for a perfect pressure fit, avoiding the need for any adhesive use.

Zip ties are hung on the length of visco to make the process more efficient.

The Sky Rocket's green fuse is long, and this will be used to our advantage; when attaching each pair of tubes, the previous two are included in the zip-tie bundle virtually guaranteeing ignition.

After each row is complete, the surplus pulls are cut from the zip ties.

The efficiency of the visco run can be seen running in an "S" pattern, with two tubes served per pass.

The rack is complete and can be considered armed.

Prior to putting this away, it is wrapped in tinfoil and taped up, making it reminiscent of a shiny store bought cake. This is simply for safety, much like a tape fuse covering found on any consumer firework.

The plan is to repeat this process with racks of 60 Air Bombs, 36 mini Air Bombs and 12 more Sky Rockets for other parts of the show.