8 replies to this topic

[pritch]

As the topic and description said. I know this stuff is solid so would be good for rocket motors but whats it like in a maroon for example? Would it be dangerous if it blasted apart or is the aim of most pyro technics to make sure the paper bursts first?

oh and I have got the powdered version so I can choose how thick I want it.

Edited by pritch, 23 April 2004 - 07:25 AM.

[Matt]

a) You should use a clay that has been used in pyrotechnics for a reason, such as powdered kitty litter and bentonite.

B.) A "maroon" shouldnt contain any clay, I could be very wrong but as far as im concerned any salute type device should be all paper, paste, string and or disks. However if you are aiming for smaller commercial type cracker devices I would still suggest bentonite or kitty litter and hot melt glue.

c) no shrapnell as the whole plug would come out and well... I suppose it would be shrapnel but not the kind that will dig into your flesh, rather feel like youve been hit by a very lightweight rock and yes your priority is to rupture the case, not blow a plug.

Hope ive answered your question and perhaps steered you into a more suitable substance for plugging tubes.

-Matt

edit- damn smilies...

Edited by Matt, 23 April 2004 - 09:03 AM.

[Kembang Api]

Hi Guys,

In the place where powdered kitty litter is not available, This is what I used

Nozzel or pluging clay:
Gybson powder 3 parts
White Porland cement 1 part

Mix well and store. When using it just damp it with water ( Very little) and mix it, till it look like it start turning into small grain.

I used it for all my rocket nozzel and end plug.

[pritch]

Thanks again mat. Even though we have allready talked on msn. Anyhow I used this stuff this morning just to make my rocket casings end plug. Basically the main problem is its very akward to handle and you can ram it down like you could clay. It squirts up the sides of the ram(or at least trys to) and just makes a mess. Its very hard to get a good straight result but I think I may have managed although I gave up trying to get it straight and ended up with like an un even surface inside. Its pretty much dried now and seems to be ok.

[chim-chim]

I've used straight, unground, clumping kitty litter w/ blue freshness crystals.
It holds with a good ramming. I don't use it for nozzles because it come's out rougher, losing performance, but I use it for top plugs on rockets, at the bottom of fountains, end-plugs for helicopters and spinners etc.
Just cheap I guess, because I have plenty of commercial grog and bentonite, but unground Litter is a little neater to use too.

[Phoenix]

I sometimes use Plaster of Paris, which is basically the same thing as all purpose filler, to plug one end of tubes where I want to composition to be loose, such as salutes or inserts. I use clay for the first plug, as it is quicker and can be rammed against the bench, but for the second plug, on top of the powder, I use Plaster of Paris, hot melt glue, or a wooden plug. These, of course, do not need to be rammed or pressed. This is necessary as doing so would solidly compress the charge or crush the stars.

In the case of ground salutes, the paper shreds or splits, and the plaster/glue/wooden plugs remain intact, but they only ever seem to go a metre at most, and do not seem dangerous. However, as Matt said, hot melt is probably safer as it is less dense. The same applys to wooden plugs. Clay plugs tend to be destroyed, which is actually safer, as the dust produced isn't going to get very far at all. That is partly why clay is preferable where possible. Presumably they do the same in the air.

For larger aerial maroons the construction is much the same as star shells - cardboard discs held in place by pasted paper and spiking. However, for a quick, easy, and very low density 20mm diameter plug, half a wine bottle cork serves nicely.

[pritch]

well so far my shell is 5 cm with an id of 10mm. has about a 10mm end plug. My casing never used any glue btw. I just wraped one layer of masking tape around the outside. Ive also cut like a pac man shap out of a piece of card and made a nose cone which is quite solid. I then cut a bigger pac man shape out of masking tape and fastened it down like that. So overall I have a quite tight, nicely streamlined rocket. made of card, masking tape and filler.

My kno3 and sulphur doesn't arrive until tomorow so im still considering what my best option would be for the nozzle.

[BigG]

Plaster of paris is used heavly in the construction of firework and is considered safe. In case of a blow through, this staff powder itself and does not present denger.

[RegimentalPyro]

B&Q do a generic polyfilla-like substance that is actually a foam. The result of this is that it is very light, strong and yet extremely resistant to heat. Once dried it can be easily drilled just by finger twisting a drillbit. It's also pretty cheap - ?1.99 for a largish tube.

Because it is foamed, I suspect that shrapnel would not be the problem it would be with a filler of a higher mass. I've used it to good effect with 5c sugar bottle rockets.

[Note to US citizens and other aliens: Pollyfilla=Spackle]