6 replies to this topic

[EnigmaticBiker]

Hello!

Not been doing pyro recently but something occurred to me that might be useful.

Had an idea that a suitable lubricant might make ball milling easier, reduce reactions with air and possibly produce a smaller particle size.

Did a bit of research and came up with the patent below.

It is done industrially, to produce reflective flakes, with really exotic solvents (organic titanates).
Other common solvents can be used, carefully selected for the metal involved.

http://www.freepaten...om/4486225.html

I have a few ideas for solvents but haven't milled metals (yet).

Anyone tried it?

[portfire]

i dont think this will work as your not only milling one compound but two or more , so if you wanted to mill kno3 with a solvent , then used it in a comp it could become dangerous.

Edited by portfire, 18 August 2006 - 08:07 PM.

[EnigmaticBiker]

i dont think this will work as your not only milling one compound but two or more , so if you wanted to mill kno3 with a solvent , then used it in a comp it could become dangerous.

I was specifically thinking of metals, not oxidisers.

A common problem (I've read about) when milling metals is the reaction of very tiny particles with air, another is sparking.
A SUITABLE solvent might exclude air and cool any "hot spots", then, when milled sufficiently, filtered or the solvent allowed to evaporate.

eg. propan-2-ol (Isopropyl alcohol) might work with Aluminium, any heat would be dispersed by evaporation (It does not usually form an explosive mixture with air).
It is unlikely to form a compound with Al or Mg at low temperatures.

I must emphasise that this is speculation about an idea that might be useful to experienced pyros - selecting the right combination is crucial.

eg. Milling Mg with diethyl ether would amount to a suicide attempt!

[fishy1]

I was specifically thinking of metals, not oxidisers.

A common problem (I've read about) when milling metals is the reaction of very tiny particles with air, another is sparking.
A SUITABLE solvent might exclude air and cool any "hot spots", then, when milled sufficiently, filtered or the solvent allowed to evaporate.

eg. propan-2-ol (Isopropyl alcohol) might work with Aluminium, any heat would be dispersed by evaporation (It does not usually form an explosive mixture with air).
It is unlikely to form a compound with Al or Mg at low temperatures.

I must emphasise that this is speculation about an idea that might be useful to experienced pyros - selecting the right combination is crucial.

eg. Milling Mg with diethyl ether would amount to a suicide attempt!

I think the ball milling a metal e.g aluminium with some kind of liquid doesn't sound like a good idea. As the air would be excluded, none of the metal could oxidise in the jar. This would mean as soon as you open the jar, the (probably flammable) solvent would start to evapourate, and all the metal's surface area would react with as much oxygen as it can get. This would pretty quickly go up in flames, lighting the flammable vapour. Not much fun. If you do try this idea, put something in with it e.g stearin to coat the metal, otherwise once the solvent evapourates you are left with uncoated, unoxidised flake AL.

[EnigmaticBiker]

I think the ball milling a metal e.g aluminium with some kind of liquid doesn't sound like a good idea. As the air would be excluded, none of the metal could oxidise in the jar. This would mean as soon as you open the jar, the (probably flammable) solvent would start to evapourate, and all the metal's surface area would react with as much oxygen as it can get. This would pretty quickly go up in flames, lighting the flammable vapour. Not much fun. If you do try this idea, put something in with it e.g stearin to coat the metal, otherwise once the solvent evapourates you are left with uncoated, unoxidised flake AL.

Fair comment.

I had wondered about the lack of oxygen preventing controlled surface oxidation, but then metals are milled under nitrogen gas.

The patent I referred to does include some very exotic solvents as well as more commonly seen ones, possibly not just to get a better surface.

Stearin is a good idea, I'd wondered if shellac (say 2%) in isopropanol might work.

Linseed oil springs to mind, but expensive and difficult to drain off.
Most non flammable solvents I know off-hand, are harmful, difficult to buy and/or expensive.

I'll have to do some further reading.

[karlfoxman]

LInseed oil s very cheap, I got 1 gallon for about 5 pounds at a garden center! I would use linseed oil for this job.

[EnigmaticBiker]

LInseed oil s very cheap, I got 1 gallon for about 5 pounds at a garden center! I would use linseed oil for this job.

You're right, what was I thinking of?!

It was past 3am.