26 replies to this topic

[pyrotrev]

It might be worth menioning an alternative method of cylindrical shell production I've seen from one or two Chinese factories. They use a "stepped" disc made from one that's the former tube ID and one the OD laminated together. These are glued into a 2mm ish wall thickness tube filled with the goodies, the whole thing is then pasted up with paper strips as a round shell would be - seems to work (even wit double breaks) even if there's no string involved.

[digger]

It might be worth menioning an alternative method of cylindrical shell production I've seen from one or two Chinese factories. They use a "stepped" disc made from one that's the former tube ID and one the OD laminated together. These are glued into a 2mm ish wall thickness tube filled with the goodies, the whole thing is then pasted up with paper strips as a round shell would be - seems to work (even wit double breaks) even if there's no string involved.

Interesting stuff Trev. For the purpose I want I will be doing something similar, but I don't envisage needing to much of a pasted layer, just enough to make it gas tight at the junctions. I have a load of 5mm wall tubes arriving next week. fingers crossed they will be strong enough.

[starseeker]

I considered the hole saw method,it worked out fairly pricey ,if they were available over here i could buy a few hundred for the same money.

If all else fails though i may have to go down this route.

[pyrotrev]

I considered the hole saw method,it worked out fairly pricey ,if they were available over here i could buy a few hundred for the same money.

If all else fails though i may have to go down this route.

If you want to cut your own from hardboard this tool:

http://www.plumbworl...tters-1822-0000

may be better. As supplied they're designed to cut a hole of a given diameter in sheet material, so to cut a disc with a clean outer edge you need to grind the angle on the cutter end the opposite way. They have to be used in a drill press or SLOW hand drill in a rigid stand, but cut much quicker than a holesaw and can be set to any size. Works well in thin MDF too, but don't think of using them in paper derived stuff like mill board or grey board.

Edited by pyrotrev, 17 June 2011 - 01:52 PM.

[starseeker]

If you want to cut your own from hardboard this tool:

http://www.plumbworl...tters-1822-0000

may be better. As supplied they're designed to cut a hole of a given diameter in sheet material, so to cut a disc with a clean outer edge you need to grind the angle on the cutter end the opposite way. They have to be used in a drill press or SLOW hand drill in a rigid stand, but cut much quicker than a holesaw and can be set to any size. Works well in thin MDF too, but don't think of using them in paper derived stuff like mill board or grey board.

Interesting find trev,i will give this some thought.

[Karl Mitchell-Shead]

Are your looking at a line of decent cylindrical salutes then Gareth?

[whoof]

Have you tried getting a quote from one of the laser cutting places ?
ISTR thy can cut stacks of material.

Edited by snert, 18 June 2011 - 10:48 AM.

[starseeker]

what size discs are you particularly after?

of all places, teddy bear makers use disks to join the legs, arms and head. they come in different diameters from 18mm upto 76mm and have a 3mm hole in the middle for the joint ropes.

this place sells them in bulk at very cheap price, £3 for 50 76mm discs, I think the discs are around 1/8th thick so if it is not thick enough you could join two togther.

Just a quick update, i have just received some 51mm and some 64mm disc for2.5" and 3" applications and they are perfect,all you have to do is enlarge the hole,perfect thickness etc,no more cutting out cardboard,

[ener]

Or do it a bit easier, especially if you don't have a caseformer:
http://www.pyro-stuff.com/hemi.html
Scroll down for the canister shell casings.

[Mumbles]

How do the breaks from the machine rolled canister shells compare to a more traditional rolled cylindrical casing? My only experience with the machine rolled tubes was with flash bag broken shells really designed to be mass launched during finales. Quantity and speed over quality in those cases.

[ener]

Breaks are perfect, just a not too thick walled casing made of a grayboard kind a like carton. These are used for commercial purposes as well. It's not the material, it's the way how you use it.

[bangkokpyro]

If you are not making thousands of discs why not use an Allpax gasket Cutter. Excellent tool for cutting thick material in just about any size you want. Just one quick turn of the tool and you have a perfectly cut disc. It will even cut 1/8 thick chipboard
A new one is over a hundred quid but you can find secondhand ones on ebay cheaper sometimes. I picked a vintage model up for 70 US, works a treat and I will never have to buy a disc again.