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What hemi next


Merlin

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I have successfully made the 4 inch ball shells so I am thinking of moving up one more time. Just from observation (maybe flawed) it appears to me the 5 inch shells are not particularly popular as compared to the 6 inch. What do you experienced guys recommend when moving from a 4?

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Everything up to 4 inch. I have not bought any hemis or tubes yet.

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Merlin 6" ball shells are the biggest shells I build. Just be prepared for the amount of composition that they take to fill.
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Merlin, I build all sizes up to 8 inch. I would suggest 5 inch. To me 5 is a great size, and is the cutoff point cost wise. I dont hesitate building some 5s and test firing them. But I rarely, if ever test a 6. 6s start to become expensive to build. 5s bteak huge.. you will love em.
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Sounds like 5's will be where I top out. The 4's are actually quite good compared to 3's. So 5's it will be. Maybe after that some multibreaks.

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My opinion differs a little bit. First and foremost, I would get comfortable and established with 4" shells. It will help you in the long run once you have them breaking nice and symmetrically, and have all the details down.

 

If I were looking to move up, I'd actually consider going to 6" instead of 5". I love 5" shells, and even still I'm recommending 6". I just feel like 6" offers a lot more opportunity for new effects and shell types. It's the smallest shell I feel comfortable building multi-petal shells in, and beginning to put complex rising effects on for instance. I've tried with smaller shells with mixed success. It just feels, to me, that the extra room available in a 6" vs. 5" makes the difference.

 

That's not to say that smaller shells cannot produce these effects. I've seen beautiful shells by a member who used to frequent here, vh718, who successfully make multi petal shells, and beautifully complex effects in shells smaller than I could have ever dreamed of. He has some techniques or skills that I apparently just don't.

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Also, give paper hemispheres some cosideration if your still using plastic. There inexpensive and you may be pleased with them. No plastic shards laying about and I think they break better than plastics. I still pick up plastic pieces and I haven't shot one in a very,very long time.
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That's funny Mum, I was thinking of VH when you said you need larger shells to make good multi-petals. I agree with you, it is very difficult and frustrating trying to make smaller multi-petals. His 4" saturn is incredible.

 

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Mumbles certainly raises some good points. It really depends on what you are looking to do. To add to what I said above, I agree that 6's certainly offer more room for inserts, double petals, etc. I guess I was thinking more in terms of cost, and shooting a bunch of them. I won't hesitate building a few 5's and test firing them, but 6's is a different story. The 6's do use quite a bit more comp than the 5's. It's a decision that is probably best made after trying em.

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Remember that a 6" shell weighs about a kilo Net explosive content, so that's a kilo of cost and time you have to make. IMO 3 and 4" shells are fine for a show with some 6's if you have the time and money. Complex effects may need a big hemi.

 

Learn about paper hemis for environmental reasons, there is a lot less clearing up to do.

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You can do a lot with fives. Personale i had rather build fives than sixes especially canisters, i guess because i am cheap. LOL.

Gregh did you build that shell?

Edited by dynomike1
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I'm with you on the cylinder part Dynomike. You can do most anything in a 5" than you can in larger cylinder shells. I guess in essence to me 5" cylinders are the smallest "big" shell, and 6" ball is the smallest "big" shell. Big meaning the size where a larger repertoire of effects becomes available or at least easier.

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I have decided although I can make shells and get some right I need to improve my 4's first and then maybe go to 5's. The 6 level sounds cost and labor intensive to produce components to load it . I will likely make some 5s when I have done all I can with the smaller ones. I have not even tried 4" canisters yet.
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When your 3" and 4" shells are good then look at the reasons to make bigger ones,

Effects- you can build more complex effects inside a big shell -inserts, leaves, petals, shell of shells etc.

Time - a big shell can take seven seconds to rise so it goes a long way up so you can use long time effects like ling hanging willow shells (tiger tail / slow gold etc) and the effect hangs for a very long time. BUT stars for a 16" shell can easily be 32 - 45mm DIA as balls or cylinders so you will use LOTS of material;

 

In the UK a professional guide to safety distance will be 1 metre for every 1mm of shell diameter or more if you can. for big shells this limits the diameter of shell that you can fire from many locations. I don't want to be within 400m of a home made 16" shell at launch and few amateur builders have that much wire or wireless firing system. Don't build shells bigger than you have space to fire safely.

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You are absolutely right . I suspect a 5 is all I can get away with max. My 4s didn't present any problem as I have 400 yards on all directions. Actually I have a mile to the west property line. Are you in England by any chance?
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The standard in the U.S. is a radius of 70 ft per inch of nominal shell diameter. Many display companies use a rule of 100 ft per inch. If you have 400 yards (1200 ft)in all directions, you could shoot a 12" shell.
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The standard safety distances are about similar, but still don't say that you SHOULD fire shells that big. They are usually suggested by insurance companies to indicate where they find the risk insurable, As most amateurs don't have insurance, it's better to err on the safer (smaller) side. Even the firer has to get out of the safety zone so either that's a lot of visco, or a competent firing system.

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Merlin, with 400yds clearance in all directions, you can build and shoot however big you like. (Obviously unless you want to build a 16 or something.. lol).

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Arthur, the only regulations in NFPA 1123 about the crew is that the firing panel needs to be 75 ft from the closest rack to the lead. 6" shells and under can be hand lit, Larger shells must be electronically fired.7" and 8" shells can be manually fired should the ematch fail and you add an additional length of safety fuse.

 

So, to be compliant one only needs to be 75' from the large shell and wearing proper PPE.

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And how many accidents happen (to amateur builders) because they do NOT wear any or suitable PPE????

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Are you referring to accidents while building or while shooting?
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I have been lurking for a while, recently made an account and have now found my first thread to respond to!

 

I have not started building yet, I am currently in the learning stage and soaking up everything I can get my hands/eyes/ears on. This is the first time I have heard the term PPE used in conjunction with the actual building of shells. I understand the need for general protection while building, and the need for full PPE while in the field, but A) is full PPE really needed while building and B) does full PPE not restrict finer movement that may be needed when building shells?

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starxplor,

 

PPE is recommended while mix certain chemicals and compositions that run a higher risk of igniting while processing the materials. If you limit the amount of materials in front of you you can get by with less P.P.E. but when you have larger amounts of volatile compositions in open containers that you are exposed to, it is worth your time to wear appropriate P.P.E.

Many accidents have occurred while making black powder, flash powder, rocket fuels etc., proper grounding and work space conditions, ignition sources, low humidity, non-sparking tools, are basic considerations when working with Pyro comps. There are a number of articles that have been written by pyrotechnicians that cover many aspects of safety measures and considerations when working with Pyro materials. (Bill Ofca is one)

Edited by mikeee
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Amen💥
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