Can I mill KP?

[Richtee]

Or is it not a good idea? Do I NEED to mill it even? Looking for a burst between BP and whistle... this a good choice?

[tentacles]

You mean KP as in, K perc and charcoal, right? *Never* mill perchlorate/fuel mixes.

 

The only exceptions I've heard of are to add a couple percent fuel to the oxidizer as an anticake while milling. This is typically done with whistle mixes as an alternative to milling the complete fuel. The chance of ignition with a very fuel poor mixture is lower than with a mix that's optimized, supposedly. At the very least, an ignition would be *far* less energetic than the optimized fuel would be!

[Miech]

Pyroguide says it can be wet milled, but that doesn't prove anything. The components however need to be very fine and well incorporated for a good performance. I'd just make a huge batch of airfloat milled charcoal and sulfur in 3:2 ratio. Wether you need BP or KP, you only need to mill some oxidizer and screen it in. Both compositions have the C and S in the same ratio.

 

I personally wouldn't mill it. That stuff has lots of power for its weight and can even be set of by striking it hard with a hammer.

[Richtee]

Pyroguide says it can be wet milled, but that doesn't prove anything.

 

Right... I had heard something of this... I knew whistle was a no-no. Thanks for the news guys...guess I'll just screen it like the whistle and try it out.

[WarezWally]

Do it

 

Whats the wortkst that could happpend?

[WarezWally]

Pardon, but unless this is an attempt at humor that isn't very good advice, IMHO.

 

Its a joke, just like when someone asked me if they could use double sided tape to stick a dryer to a wall

 

/C2H6O

[TheSidewinder]

Stick a dryer to a wall????

 

This requires more details.

[qwezxc12]

I know that this topic is essentially closed, but I thought the following info is worth sharing, mostly because the chemistry of pyrotechnics is often lost in the process. From a post on rec.pyrotechnics by Mike Swisher:

 

A useful gauge of the relative "stability" of oxidizers is may be had by comparing their heats of decomposition in kcal/mole. From Conkling's "Chemistry of Pyrotechnics," they are respectively:

 

Potassium nitrate +75.5

Potassium perchlorate -0.68

Potassium chlorate -10.6

 

Potassium nitrate requires the constant input of heat from other sources (the combustion of fuels). Its decomposition is endothermic by itself, therefore not self-sustaining.

 

Potassium perchlorate does not require a great input of heat from the combustion of fuels, its decomposition being mildly exothermic. Hence, compositions based on potassium perchlorate do not require the initiation energy that those made with saltpetre do, are accordingly more sensitive, and must be handled more gently.

 

Potassium chlorate is substantially more exothermic in its decomposition than potassium perchlorate. It easily sustains its own decomposition once that has begun. This is why compositions made with chlorate exhibit greater sensitivity to initiation than do those made with perchlorate, and much greater sensitivity than those made with saltpetre.

 

Saltpetre-based black powder can and many times has ignited in the process of milling, even though saltpetre decomposes endothermically, and black powder is thus relatively insensitive to shock and friction. Hopefully this helps to clarify why it is not a wise idea to ball mill or otherwise grind perchlorate compositions.

Edited December 26, 2008 by qwezxc12

[Mumbles]

Yes, just screen the KP. I find charcoal is the key component here. Commercial airfloat doesn't have the oomph to get good breaks. I've used both cowboy brand and willow charcoal with excellent success.

[Swede]

A good topic for APC would be "screen machines." I refer to devices other than ball mills, or manually screening, to gently mix sensitive chemicals; forms they come in, and how to make them. Shimizu goes into some detail, and many of the threads on flash discuss mechanical options to diapering.

 

Whether to use such a machine (like PVC "cups" mated together, then inverted repeatedly) with a particular comp, requires experience, but it would be an interesting thread. Comps like whistle, or KP. Obviously static needs to be dealt with. I guess the reason I'm thinking of this is because such a device can be far more remote than working a screen. You can have some sort of blast shield between you and the comp being mixed.