safety concern

[AUBE]

i was sitting at my sander the other day after a week of grinding carbon steel, admiring my mini-mountain of iron dust rapidly turning into rust. i was getting started on grinding some aluminum when it occured to me this may be dangerous.

aluminum dust and iron oxide(rust) mixed form ferroaluminum thermite which is a very impressive incenidary, it will vaporize carbon steel and turn sand into glass near instantly. its a bit hard to light but i know magnesium sparks will ignite it...im also thinking titanium sparks would too. i dont think this is a huge concern because the dust has to be mixed in the proper ratios, then hot sparks to ignite it, but i thought i would mention it before a freak accident occurs and someone loses a leg. if your a messy workshop kinda guy like me, you may want to sweep between grinding these materials.

-jason aube

[Ed Caffrey]

I agree! Letting dust accumulate around your grinding area is asking for trouble. At one time I owned a dust collection system, but found that a spark from grinding steel could easily turn the whole thing into a melt down.........hence, I no longer use a dust collection system.........just buckets of soapy water suspended benieth each grinder.

[Chuck Bybee]

Ed,

Next time you are over here I'll show you how we use a spark quench bucket with our 1800 CFM dust collector. We used to have about one small titanium dust fire per month before we combined the DC with the bucket.

I think it is important to remove the smoke and fumes caused by grinding from the area. If you are grinding 6-4 titanium and see sparks, the smoke from the sparks contain vanadium which can be inhaled. If you breath enough you will get VERY sick. I suppose the high vanadium steels could also be a problem.

Titanium and steel grinding dust mixed together is much more flammable than titanium alone. Does anybody know why? The resulting fire burns much faster than a titanium fire. It looks almost like flash powder!

[AUBE]

now that you mention it chuck i recall that thermite is a mixture of iron oxide and any reactive metal(aluminum, titanium, niobium, etc)...so that flash fire is probably a poorly mixed thermite lol.

some nasty stuff, the military even puts in in gernades and uses them to destroy classified materials if they are about to be captured