Firewire and canisters

[genereyn]

I'm going to use Firewire initiators to launch canister shells. A couple of methods have been described to do this. One is to poke (using a brass awl) a hole through the bottom of the shell. The other is to poke through the fuse hole in the side of the shell. In both cases the initiator, with the shroud in place, is inserted through the hole into the lift charge.

I like the idea of the bottom poke because it's easy to do and seems to me like there would be less restraint on the shell as it lifts out of the mortar.

The "problem" I encounter, however, is that the shroud, now vertical, doesn't penetrate nearly far enough into the lift charge from the bottom in order to simply cover the initiator and the hole with a piece of tape. The lift charge cavity is already filled with black powder and there doesn't seem to be room to accommodate the length of the shroud. Removing the shroud certainly would work but doesn't seem like a good idea. It also doesn't seem right to leave part of the shroud sticking out of the bottom of the shell preventing the shell from sitting on the bottom of the mortar.

Inserting the initiator through the fuse hole in the side is also easy to do and the shroud, now horizontal, doesn't take up much more space that the original fuse. I'm just concerned that this placement might tend to more restrain the shell as it lifts.

I'm aware that in either case the initiator wires themselves should be restrained either by a screw in the rack or by a hole near the top of the mortar.

[MtnViewPyro]

I have never seen going through the bottom, so I will not comment on that. However, I have shot a ton of shells when I poke where the fuse is. With this method, the hole is almost created for you already. So, you really don’t mess with the integrity of the shell. To ensure the firewire stays after ignition, I just use the screw method. Below is a video of me doing it. I might be proven wrong, but I think this option would be your best option.
https://youtu.be/1IkLqwddJu4

[Rick_In_Tampa]

I can't think of any good reason to poke a hole in the bottom of the shell. Especially when you already have a hole in the side that leads to the lift charge. The wire from the initiator isn't going to take up any more space than the original visco fuse that you're replacing. So that's a wash. Going through the side IMHO is the only way to do it.

[genereyn]

Allow me to pursue this a bit further. If I use the "double-loop" method of securing the initiator wire through a small hole drilled in the top of the mortar, what prevents the lifting shell from taking the mortar with it? And, regardless of the securing method, "double-loop" through the hole, or wrapping the wire around a screw in the rack, what typically happens? Does the wire break at the securing point or is the initiator head ripped from the rising shell?

[cptnding]

Just to give you another point of view.....
Most of the time I use fuse on mortar racks. To me it is faster and cheaper and takes up less cues. The only canister shells I have used that are reliably marked for effect are the 76 Super Nova shells so generally I only use canisters for "sky puke" moments and finales. I use a ton of Excals because they are the best price due to proximity of a Jakes warehouse close by. I think they are top notch shells bit the effect labeling is a joke.
When I want one at a specific point in the show I use Firewire and place the match through the bottom. For me it seems quicker. Some shells have a thin disc on the bottom and some only have paper so I find it faster to poke a hole there as opposed to going in through the fuse hole. If you do it this way don't try to go straight in with the match. If you slide it in at an angle as if you are trying to lay if flat against the bottom you will have no problem. Same angle as if you were going in through the fuse hole. Small piece of tape over the hole and you're done. I've poked through the fuse hole and it seems to take more time to me because you have to enlarge the hole to fit the match shroud.
As for securing the wire I've done it both ways and looping it around a screw is much easier. If you do secure it to the tube it's not going to pull the tube out. The velocity of the shell coming out of the tube will break the wire instantly. For me it looks like the wire usually breaks at the match head. When I go through the bottom the match head and wire are always intact. I guess it may give a little more resistance to the shell if you are going in through the fuse hole but you are not going to notice a difference in height.
Either way you do it will be fine. Just go with whichever method you like.

[MtnViewPyro]

The wire appears to break most of the time when wrapping it a few times around a screw. I agree with cptnding, efiring shells takes up a lot of cues. The more I get into efiring, the more I get away from shells. Sky puke and filling sky is almost all I look to shells for now.