Aluminum and magnesium powder

[austar]

What is everybody's thoughts on useing aluminum and magnesium powder made from a fine linishing belt?

I understand why ppl like flake and the such due to the corners lighting easier compared to spherical, but powder from a linisher would have fine edges and heas and tails that would be easy to ignite, well in my experience anyway lol

[Limpy]

You're probably going to have to explain what a "fine linishing belt" is. I have been in the metal trades for 20 years, and I have heard the term, but I cannot explain exactly what that is, though I could take a stab...

[NeighborJ]

There are several problems I see with any kind of abrasive process used in creating powdered aluminum. Whether filing or sanding the aluminum particles always seem to plug up the grit and edges of the sand cloth. I've tried this and have found the best type of abrasive is a flapper wheel or (tiger paw) grinding wheel. The problem with these is the fact that they wear and contaminate the powder with bits of cloth and AL oxide. The second problem with this method is the fact that the freshly exposed AL is pyroforic without its protective layer of oxide on its surface, this is why AL gets so incredibly hot during any sanding process. It is really quite dangerous when manufacturing any quantity of fine AL without the SLOW introduction of oxygen during the process.

[OldMarine]

A linishing belt is simply an abrasive sanding belt. I don't think I'd use the fines from that process because they'd contain a good portion of the abrasive along with the metal. I must admit though that a mixture of steel and zirconium would make an interesting gerb!

Edited December 28, 2016 by OldMarine

[austar]

Ok to explain better, i am a metal polisher by trade. The final sanding stage is useing a 400grit belt. My machine has a enclosed belt apsrt from the contact area, the majority of dust gets caught in this area, but the really fine airfloat stuff seems to collect in rear pulley wheel, i have been collecting this and seems to work fine, but never having used anything else to compare it to, i was promted to ask the question.my magnesium i use a courser belt due to it clogging, but put up moist screens to collect the fines and use a collection sheet for the courser material , it is fine for flash, and have had success with my carbonate red stars.

[Limpy]

The second problem with this method is the fact that the freshly exposed AL is pyroforic without its protective layer of oxide on its surface, this is why AL gets so incredibly hot during any sanding process. It is really quite dangerous when manufacturing any quantity of fine AL without the SLOW introduction of oxygen during the process.

 

That isn't a problem. We used to grind lots of aluminum, using pneumatic grinders with sanding pads. It heats up due to the friction, but NEVER caused a problem. Some days, we completely coated the 16x16 room we were in. Yes, there was no dust collection. I suspect that in order to have a pyrophoric issue, you'd have to sand/grind/process it to a much smaller particle size than standard metal working does.

 

OP, if it's working, and it's free, why not? BTW, are you talking about a timesaver?

Edited December 29, 2016 by Limpy

[NeighborJ]

When i read the post the first time i was envisioning someone leaning on a chunk of al trying to wear away the metal against the belt sander. this could create a possible issue, but this is not the case. Austar is mearly collecting the dust created from the pollishing process which should have had time to oxidize slowly and as Lumpy stated ,it is not an extremely fine powder. I see nothing wrong with collecting this dust for pyro use.

[Mumbles]

I would be a little uneasy using it in flash due to the presence of additional abrasive particles. If it works, go for it though. Do you have access to a microscope or anything to get an idea of particle size or the particle shape? My best guess would be irregular but granular, but it'd be interesting to know for sure.

[austar]

Magnesium in flash has worked well for me so far.

I am keen to see the dust off the 400 belt under the microscope to judge the structure and shape of the particales.

I have access to a microscope at work for checking our aluminum so i will try to get on it and have a look. But my guess is thatthat the particales will be ribbon like. So we shall see lol

[kleberrios]

[OldMarine]

How long does it take to make a pound of powder that way?