Ceramic casings

[xoo1246]

My mom does ceramics and has an owen where you could make ceramic pieces. I was thinking that maybe one could use something like this:
<a href="http://w1.478.telia.com/~u47802930/P5210001.jpg" target="_blank">http://w1.478.telia.com/~u47802930/P5210001.jpg</a>
<a href="http://w1.478.telia.com/~u47802930/P5210002.jpg" target="_blank">http://w1.478.telia.com/~u47802930/P5210002.jpg</a>

to make beautifull pyrotechnic shells both before and after use. I remember reading that the chinease used ceramic dragons filled with BP to scare their enemies. I'm only spawning, hope you don't mind. Anyone has any other ideas how you could use ceramics or the owen.
Oh, and the fragmentation from thease wouldn't be that nice(sharp).
Another thing is that I can get inexpensive metal oxides when she orders clay.

<small>[ May 21, 2002, 03:43 PM: Message edited by: xoo1246 ]</small>

[kvitekrist]

I know pirates used clay grenades filled with BP.

something like this:
<img src="http://home.no.net/gjalring/sp/gr.GIF" alt="" />

made in 5sec :)

[inferno]

Itd throw some nasty shrapnel, pretty much like glass, and would be much heavier than plastic. A good casing for stars is the plastic containers out of kinder surprises, and i saw a post with little plastic egg things which were pretty much the same.

Overall i think youd be much better off with paper or plastic casing, the ceramics would be heavy, a bit harder to load, and more dangerous. Also, if you accidently dropped one, it would smash.

[Microtek]

A low-explosive filler would likely cause the case to rupture before all the filler had deflagrated and would sling unpleasant fragment around - stoneware is notoriously poor at withstanding stretching forces. However, if a high-explosive filler was used, the casing would be pulverized by the shock, and only relatively harmless dust would be the result. A possibility for an offensive type hand grenade.

[xoo1246]

Yeah, it's very brittle, I didn't think of using it IRL, only playing with tought. You could make grenade bodies, but then you could use plastic as well and with better results(strength,elastic)

[xyz]

If you're talking about using it in grenades then it would be a lot better than plastic because it is heavier and the shrapnel will have a lot more kinetic energy stored in it.

[Zambosan]

Not at all. It's a crystalline solid, so it'll cleave pretty easily and the internal pressure will not get near what it would with a tough plastic shell. The velocity of the fragments will be much lower, and even though they're heavier, K.E. = 1/2 m*v^2.

[Bitter]

How about vacuum forming thick plastic instead ? Apparently, it can be done from home relatively cheaply.

[Arkangel]

How about casting something with GRP resin?

First you take a latex moulding off a pineapple grenade, then you
make an inner case by wrapping glass rovings around something like a bit of inflated innertube, wetting them with resin and then letting them cure. After that, you pop the casing inside the mould, and fill up around it with casting resin (with minimal catayst/accelerator, as it will overheat and crack all over and be very weak.

Once that is all cooled down and cured, you take off the latex mould and then you have a nice, neat hollow body, ready to fill.

[inferno]

Ark: i assume glass rovings are glass shavings or something? It'd shatter. I think the best "grenade" is a crater maker with a soda bulb (CO2 cartridge). But anyway back to topic, plastic or paper would be much better for fireworks, lighter(=less lift charge, more height etc), less dangerous, easier to load, not susceptible to shattering...

[Arkangel]

Fibreglass rovings are a kind of string made with glass strands, used either in a cloth called "woven rovings", in a "chopper gun" for spraying the glass/resin mix onto a moulding, chopped into smaller pieces for casting, or the way I'm describing, wrapping round and round a moulding along with the resin. On a larger scale, they make grain silos from this material, winding it on like a big cotton spool. For this application it would be really strong, and you'd get a pretty high bursting pressure.

[Bitter]

I suppose it would be possible, but the resins used for fibreglass are not the most suitable for the desired purpose. Polystyrene is a pretty brittle plastic even with the glass reinforcement. Epoxy would be a little better, but pretty expensive. I'm going to attempt to try vacuum forming 3mm PVC in the not too distant future. I'll tell you how I get on.

[Arkangel]

I've worked with GRP for much of my life, and I can say that it is a very little appreciated material in terms of strength. If I talked about Carbon or Kevlar rovings then people would be more impressed, but not based on massive experience. Fibreglass is reputedly stronger than steel, weight for weight. The trick with something like this is getting your construction so that it bursts evenly.

GRP is made with polyester resin, which I think is a quite different material to Polystyrene. I have stopped a .22 LR slug with 6mm of GRP laminate, so with most LE's it shouldn't just shatter. Plus if you surround the central container in an exterior of resin (shaped like a pineapple grenade) It's going to shatter along the break lines of the mould.

Moving it slightly back on topic, when we're talking about fabricating bursting casings, I thought about casting in plaster of Paris. With BP it might be effective do you think?

<small>[ May 31, 2002, 11:16 AM: Message edited by: Arkangel ]</small>