42 replies to this topic

[PanMaster]

You could build a press by using flowing water. Connect a 2-way tap to a source of blasting water, and make one smaller and attach a tube to it securely with PVC tape and resin. Put what you want to press inbetween two sheets of wood or metal inside a big plastic bag without any holes. Connect the bag to the tube and make sure its air tight. In theory you can get 10 tonnes by drawing air from the bag due to the action of water carrying it away, no expensive devices required.

[Richard H]

That is fascinating stuff! Are you into mechanics?

Pressing means taking a loose, powdered composition such as black powder and pressing it under high forces (several tonnes) into solid powder 'cakes' ('pucks' for y'all 'merican folks).

Once you have your pressed black powder cake you break it up into grains and sieve it to ensure the product is a powder of uniform grain size. This is called corning.

For more information please click here

[BigG]

Pressing and corning would not necessarily ?improve? burn rate. The idea behind corning is that it increases the surface area that can ignite and allow fire to flow between the corned grains. Let me try to explain.

Imagine black powder pressed into a fountain. The only ?exposed? layer is the top of the fountain. When that layer ignites ? it ignites the layer under it and slowly advances down the layers until reaches the bottom of the fountain. The fire cannot advance quickly because only one layer is available for ignition.

Now imagine corned (!) black powder just drops into the fountain. When you ignite the top layer ? since there are spaces between the corned black powder, the fire just shoot down and ignite the whole fountain almost instantly. The force of the ignition causes the gases created by the fire to ?blast? out of the top of the fountain. This is why corned black powder is also called ?blasting powder?.

So the same powder have the same burn rate, in both corned and powder state ? but by corning we allow more of it to catch fire simultaneity.

I?m horrible at explaining things hope someone out there understands me

BigG

[Pyromaster2003]

hehe, was a very good explanation. it will be like Black Powder coated rice hulls i think, wouldn't it? the air space between them will allow fire to shoot around the bigger surface area. thats why a pile of rice hulls will burn faster in the open than a pile of black powder.

[bernie]

The same principle applies to quick match. Ordinary black match burns at a rather slow rate but if you take 3-4 strands of the stuff and wrap it up with a paper casing it burns very quickly indeed. Again suface area. Directional to boot. Shimizu explains many of these principles in Art,Science and Technique.
I have not checked the link that Mr. Honcho referred us to(because I know it all already:rolleyes:) but should it fail to mention that the corning process is possibly the most dangerous aspect of bp manufacturing, then I just did.

That is a useful link to be sure. I have constructed a corning tool (for the challange)that uses two adjustable rollers. One roller is made of large BRASS hex bolt stock and the other is an alum. roller approx. twice the size and has circumferential(?) groves cut one right next to the other. The brass hex is the hand powered part and the alum. roller is the idler part. I guess you could call it a puck eater. Along the lines of an industrial mop ringer. It ain't a pretty thing but it is functional and you are able to regulate the size of the grains. I was ending up with to much meal D. Clamp it to a bench and of to corning land you go. Is it practical? I don't know. It was fun and educational to build. Do I use it much? No. I just buy the stuff.
If your real hardcore and want real consistency in the puck/cake (desired grain density)you can adapt a pressure guage to the bottle jack or a torque wrench to an arbor press.

INTERSTITIAL I think they call it.

[Edited on 27-5-2003 by bernie briden]

[PanMaster]

This is the UK:rolleyes:
You can't just buy stuff here, anyhow, wheres the fun in buying pre-made compositions? A real pyro makes his own stuff

[Richard H]

Originally posted by PanMaster
This is the UK:rolleyes:
You can't just buy stuff here, anyhow, wheres the fun in buying pre-made compositions? A real pyro makes his own stuff

Yes you can, I have the paperwork to buy black powder! But I agree also that making it yourself is more fun.

[bernie]

Every fireworker worth his weight should at least be able to make good BP. I'm just talking about lift. The other part of fireworks that include any bp components should be made yourself. Otherwise you might as well just go out and buy ready made fireworks. No fun in that at all. Your just lighting matches. This of course does not apply to the good people that display them.

[Pyromaster2003]

a pyro today mensioned about how he seen on TV about the Chinese using BP coated rice hulls IN stars! i have never heard of this before and i think they may have said about BP coated rice hulls being used to ignite the stars in shells. does anyone know if the Chinese do infact add BP coated rice hulls to their stars!?

And while were on the subject, does everyone on here just make pulverone and granulated BP from 'pucks' to produce a break/lift charge or does anyone have any success in producing good quality BP coated rice hulls/grass seed...? I tryed a while back with no success.

[PanMaster]

use ammonpulver as a lift charge, its a powerful gun propellent.

[Pyromaster2003]

yes i use pulverone as a lift and burst but just wondering if anyone had any luck with BP coated grass seed?

[BigG]

a pyro today mensioned about how he seen on TV about the Chinese using BP coated rice hulls IN stars! i have never heard of this before and i think they may have said about BP coated rice hulls being used to ignite the stars in shells. does anyone know if the Chinese do infact add BP coated rice hulls to their stars!?

And while were on the subject, does everyone on here just make pulverone and granulated BP from 'pucks' to produce a break/lift charge or does anyone have any success in producing good quality BP coated rice hulls/grass seed...? I tryed a while back with no success.

I think they probably meant BP coated rice hulls inside shells to ignite stars.

[phildunford]

As I understand it inert seeds etc are coated with bp to give them more surface area and to take up space in big shells. I don't think you need to fill the spaces with pure bp - more power than required and expensive. You do need to fill the space with something, or you will get poor breaks and 'set-back'. Bulking up with hulls etc does the trick...

[BigG]

As I understand it inert seeds etc are coated with bp to give them more surface area and to take up space in big shells. I don't think you need to fill the spaces with pure bp - more power than required and expensive. You do need to fill the space with something, or you will get poor breaks and 'set-back'. Bulking up with hulls etc does the trick...

Almost there. The reason that you don't use only bp is simply becuase it is too much fire power. It will break your stars to pieces before they leave the shell.