What's new
What's new

Thermite/aluminum powder

The OP also mentions black iron sand ...this is a mineral complex and very heat resistant .....the stuff used in iron making was bog iron,pure iron oxide from the reaction of iron salts in water and oxygen from algae.........the importance of the black iron sand is that it is an indicator of gold.
 
The largest of the little punched steel slugs are probably about 1/4 " dia.
That's to add iron mass to the weld, not to sustain the thermite reaction. Like 7024 or 7028 welding rod, with extra iron powder in the rod flux.
They probably light off a railroad thermite charge with a pretty substantial piece of magnesium, or possibly an oxy/acetylene torch. So the coarser grind of the reacting material doesn't matter as much as for a classroom demo where the instructor has a little-bitty 1/4" wide strip of Mg to start things off with.
 
The OP also mentions black iron sand ...this is a mineral complex and very heat resistant .....the stuff used in iron making was bog iron,pure iron oxide from the reaction of iron salts in water and oxygen from algae.........the importance of the black iron sand is that it is an indicator of gold.
Where did I mention black iron sand?

I agree with you all about the stump not being able to sustain a burn. My plan is to drill a few vertical holes with air holes drilled on an intersecting angle to see if they will draw in air. One thing that worked is placing my lawn mower next to the smoldering stump. It lit the top of the stump up and I could see the stump shrink, ever so slightly, into the ground. It was a very slow, but interesting process.
This stump is an old pine tree. It is completely, "fat lighter", at this point. It is also rock hard.
I'm going to sift out the finest aluminum from my pile and mix it with the manganese. I'll report back with the results. For any safety Sallys I'll wear a condom.
 
Last edited:
I have no personal knowledge of this incident, but I'll pass it along anyway. A small family repair shop, perhaps a father son enterprise, had an all purpose bench grinder. One day while grinding some steel part there was a very large flash of light which temporarily blinded the operator for a few seconds. His hands were in a great deal of pain. When he could see again, he saw that the skin on his fingers was hanging loose in places. After recovery, the cause of the incident was that this grinder was used for many grinding operations. The accumulation of rusted iron filings (iron oxide) under the grinding wheels along with aluminum grindings mixed together were probably ignited by the sparks from grinding the steel that day.

Bob
WB8NQW
 
For what is worth. On a 8" bench grinder with 3M non woven wheels in the aircraft hanger. I was just going to take the burr off a piece of 1/8" 1018 flat stock. I noticed sparkles on the bench. As it turns out there was a light coating of aluminum & iron dust on the bench that was burning. I knew better shame on me. All it took was the small sparks from 2 inches of work to set the dust mixture alight. When the dust lit up it traveled like a glow worm 2" before going out. I had been telling folks not to mix metals do to the possible hazard of a thermite reaction.
 
We used to buy powdered metals ,and always on the drum was "Non Reactive Grade".......which I took to mean something was done to stop the metal powder being used for nefarious purposes..........one time,they dumped 8 tons of Zinc powder because it "had lumps in it " and the painters refused to use it.
When you get to a certain mesh, zinc powder, more commonly, zinc dust, becomes pyrophoric. So hence the reason "non-reactive".
 
Are you saying it’s not safe for me to belt sand aluminum and steel on the same station throughout the year? I cot a cake of dust under that lol harbour freight unit………
Seriously. It’s that a hazard?
metal dust is a SERIOUS hazard. basically, any accumulation of metal dust is bad, except maybe pure gold. (that's a nice problem to have if so, haha!)
but no joke, most metal wants to react with oxygen in the air, and some will do that with vigor. Magnesium of course is a well known example. that's a violent reaction.
having said that, the Thermite reaction is NOT iron and aluminum reacting. it is the O2 in iron oxide deciding it likes aluminum a LOT better, and jumping ship from the iron releasing a whole shitton of heat/energy as it does. iron or steel dust will oxidize given enough moisture and time, THEN it risks becoming a thermite reaction. it's not a problem to occasionally use the same machine, but don't let dust accumulate, clean daily is good practice, and when switching from iron to AL.
im not familiar with Manganese -aluminum reacting, why are you using that? seems a whole lot harder to come by than iron oxide?
 
Manganese is readily available through pottery distributors. I purchased this for another project that I never ended up doing so I used it because it's what I had.

so its oxide? will it even work?

sounds like the story of the guy looking on the ground under a street lamp, friend asks "what are you looking for? guy says "I dropped my keys down the block" friend says "so why are you looking here?" guy says, " well silly, its too dark over there, can't see a thing!" :D
 
Manganese is readily available through pottery distributors. I purchased this for another project that I never ended up doing so I used it because it's what I had.

Do you by any chance mean Potassium Permanganate ? Blackish powder that turns water red/purple ?
 
Manganese dioxide is used in phosphating to produce a black deposit ,and is quite cheap...........anyhoo ,as to metal dusts ,a well known cause of fire in workshops is a reaction between aluminium swarf and wood saw dust ,when both materials are sawn on the same bandsaw.
 
Manganese dioxide is used in phosphating to produce a black deposit ,and is quite cheap...........anyhoo ,as to metal dusts ,a well known cause of fire in workshops is a reaction between aluminium swarf and wood saw dust ,when both materials are sawn on the same bandsaw.
Yes, this is what I originally purchased the manganese for. From YouTube it appears that it takes more heat for this formula to kick off compared to the iron oxide mix.
 
Manganese for pottery is manganese dioxide.

The best aluminum powder is made with an oscillating sander atop a plate of aluminum. Iron oxide was generated en-masse in my electrolytic cell that I generated hydrogen with. Magnesium was used for ignition, from a boy scout fire starter provided ignition.

You could make awesome little igniters by cutting the glass tip off a christmas light, then filling it with powder from a crushed estes rocket engine. That is of course once you have used up all of the shellac / gunpowder ones that came with the engine pack.

It's amazing I left high school with all my limbs and no record. But then this was back when the science teacher taught us to make flash paper for the drama club's stage effects. Different times.
 
The zinc powder would go solid in the filter body of the Graco airless ........to get it out was a major job,like chipping rock......but I discovered if the filter was heated with the oxy,the contents would go off with a loud bang and shoot the plug of zinc clear across the yard and smash against the back concrete wall of the paint store.
 








 
Back
Top