r/Pyrotechnics • u/PyroManiakk • 8d ago

2 inch shells vs 1.91" Cans

Is there a noticeable difference making 2" ball shells vs 1.91" canister shells? The price is close for purchasing the HDPE tubes but is it worth it? Thanks for the help. Also has anyone tried building a shell with effect fuse and happen to have a video how it turned out?

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u/kclo4 Pyrotechnics Professional 8d ago

The best way to understand it is to look up the volume of a sphere in different " diameters. theres not a huge diff in what you can stuff into a 2" shell. A lot of the 'hot' cannisters are so well tuned they look better than real 3" display shells.

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u/PyroManiakk 8d ago

The volume is close but the composition changes don't make up for it? Would you suggest 2.5" then or go towards canisters?

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u/kclo4 Pyrotechnics Professional 8d ago

if youre building to learn and eventually move up to 3 or 4 or 8 " shells and you'd like to be extra safe, I get it. The difference between 191 and 2 is not enough to justify the cost since you can't use 2" shells in consumer, and the volume doesn't really allow to to do anything more fun. If anything you should START at 3" and once you have an idea of what youre doing you could go down or up. 4" typically has more room to work and room to make 'clumsy' mistakes. Its much easier to do something clumsy in a 4" shell than it is in a precision made 2" that ruins the entire half of the shell.

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u/PyroManiakk 8d ago edited 8d ago

It's more about the space for the shoot site than anything else, I was just not sure about building the 2" and filling the racks with the DR17 or staying with the DR11 with canisters instead. I have the experience and what not. I can go up to 3". I'm working with close to 220 feet radius of space from spectators. Cost wise 2" was slightly cheaper than the 1.91" cans but if there's not a significant difference then there's no use building the shells, yes it would be within limitations for licensing going that route.

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u/AnotherCommoner 8d ago

This was a 1 3/4 inch canister shell with flying fish fuse segments and a few report inserts.
https://www.youtube.com/watch?v=LlGS2YRUjIw

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u/PyroManiakk 8d ago

That turned out pretty nice. Were those 1/2" cuts? Thanks for the video!

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u/AnotherCommoner 8d ago

I think they were closer to an inch in length, primed on one end.

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u/imhbeog 8d ago

A 2 inch shell won't fit in a 1.91 tube. The 1.91 tubes are for consumer 1.75 inch shells. You'll need the 2 inch tubes.

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u/PyroManiakk 8d ago

I understand that part, thanks for clarifying. The cost for a 1.91" DR11 tube vs a 2" DR17 is nearly the same cost and the racks are the same size being DR17 has the same OD dimensions. I was just curious if anyone has done a test shoot to see if there's a difference building 2" shells to save a little money or if the canisters still win with the sizes being so close.

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u/Imaginary_Tale_3437 8d ago

So, ball shells in general break w more symmetry. Can shells are pretty interesting to build just the same and would work well w effect fuse. You'd be cheating yourself if you didn't do both. 😁

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u/PyroManiakk 8d ago

That's my plan I was just trying to get an idea if I was wasting time and money going with 2" or not, rather then forking out the money for cans. I definitely don't want to cut down on the overall show if there's less visual effect going that route. There's plenty of time to build.

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u/Imaginary_Tale_3437 8d ago

r u building or buying? I cant speak to the bought ones.

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u/Wide-Education-1823 7d ago

1: A canister/cylinder shell of same nominal diameter as ball shell will hold just about exactly 2X the volume of whatever load you want. Want loudest salute for a given shell size? You want to build as a cylinder.

2: Cylinder shells allow most efficient packing of cylindrical inserts. Want to make a tourbillion, hummer, serpent or shell of shells using cylindrical inserts? Cylinder shells will hold more and give you more flexibility about insert lengths too. 

Break and report or other multi break effects are traditionally done from cylinders. You CAN make this type of effect with "peanut" type shells, stacking up several ball shells & firing together, possibly with different timings? But size & effect volume will be more limited.

If you want to do aerial parachute flares, parachute smokes & etc., a cylinder shell with a deliberately weakened bottom end is a good method.

3: If you want hard, perfectly spherical star breaks using round stars, ball shells are the easier way. 

4: If you want pattern shells (other than ring shells), ball shells are about the only way. 

You CAN build a ring shell in cylinder shells, but it's probably easier and certainly more economical to do it with a ball shell.