Grinding aluminium - explosion risk

[fv1609]

Came across this which is rather sobering. My workshop has all sorts of dust & crud etc

 

http://www.hanford.gov/rl/?page=542&parent=506

[Enigma]

Didn't know that...

[Pete Ashby]

Nasty, lets hope our local friendly local terrorists don't read the same report !. :-(

 

As an aside it's bad news for a whole rang of reasons to grind "soft" metals like aluminium brass and copper, the inhalation of the dust is really bad news, aluminium will give you a very nasty silicosis and copper will poison you.

 

As if that's not bad enough you run the risk of the grinding disk exploding if and when you use it on steel as a result of particles of the soft meal becoming embedded in the wheel. This produces localised heating and expansion as a result of friction when grinding steel or cast iron.

 

Wheels at work used to have a big sign saying NO NON FERROUS METALS TO BE GROUND.

 

Pete

[Jessie The Jeep]

Any fine dust can be explosive, wood, metal, flour, custard powder!!

 

I seem to remember a news article in the 70's or early 80's about an explosion at a custard powder factory.

 

So remember to extract, ventilate, and think about possible ignition sources. ie don't go welding as soon as you've finished sanding or grinding etc.

 

Steve

[berni]

the great fire of London was started at a bakers by combusting flour. weird when you think about what flour goes into making.

berni

[Jack]

Yes we had a flash in one of the pig buildings once. The building hadn't been washed for a long time as it hadn't been used so once we put some stock in there they stirred up all the fine dust particles at the same as the gas clicked on and ignited.............this flash went across the room in miliseconds but nothing was burnt :schocked:

[Mark]

That was lucky Jack, could have been eating bacon for a long time after :rofl:

[GlosterMB]

The three storey factory where my father worked in the late sixties burnt down, that was an old Birds custard fatory at Ashchurch, Glos. The word was that custard powder had got under the floor boards and somehow ignited, you could see it burning from miles away :evil:

[ashchurch frank]

not only aluminium, manganese burns very well! most non ferrous materials can ignite in a powder like state. note that aluminium and steel should not be fastened together ie riveted,bolted etc unless coated or seperated. they act together like a battery and can generate heat and ignite.

[Larry Hayward]

Frank,

 

Its interesting what you say about Aluminium and Steel which should not be bolted together - you see thats what my Lightweight Land Rover is made of! So is did they paint all the bits before assembly or is my Lightweight going to burst into flames one day!

[sirhc]

generate heat and ignite.

 

 

I thought they just corroded! But then what do I know, I'm just a materials engineer..... :roll:

 

Chris

 

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Galvanic corrosion occurs when a galvanic cell is formed between two dissimilar metals. The resulting electrochemical potential then leads to formation of an electric current that leads to electrolytic dissolving of the less noble material. This effect can be prevented by electrical insulation of the materials, eg. by using rubber or plastic sleeves or washers, keeping the parts dry so there is no electrolyte to form the cell, or keeping the size of the less-noble material significantly larger than the more noble ones (eg. stainless-steel bolts in an aluminum block won't cause corrosion, but aluminum rivets on stainless steel sheet would rapidly corrode.