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I Forge Iron

Warning! Warning! Warning!!! Thermite


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While I do not want to detract from any warning which may prevent an accident, please be aware that:-

Thermite is a reaction between Iron Oxide and Aluminium powder.

There is no danger (from thermite reaction at least) with the abrasive powders made from Aluminium Oxide. 

Aluminium Oxide is produced by the thermite reaction...it will not burn twice.

Please check on the chemistry for yourselves and do not take my word for it.

Alan

 

On 15 April 2016 at 0:03 AM, Alan Evans said:

I used to pickle my ladles and bowls in phosphoric acid and follow up with a wire brush burnish.

I now find it more efficient to blast them (chilled steel shot or aluminium oxide for mild steel, virgin aluminium oxide for stainless steel)  to remove the oxide and again follow up with wire brush burnish.

You can buy small spigoted cup brushes which work perfectly well in the chuck of a pillar or bench drill (drill press).

Alan

 

On 16 April 2016 at 2:11 AM, WayneCoeArtistBlacksmith.c said:

Be extra careful when using aluminum oxide or virgin aluminum when scaling steel.  You do not want to form Thermite.!  See the thread Warning! Thermite.

You do not want to burn or blow up your shop or yourself!

 

On 16 April 2016 at 0:56 PM, Alan Evans said:

Thank you for the warning. I certainly don't want to blow myself up...and I don't want to form Thermite accidentally...however I think you may have mistaken the chemistry. The Aluminium Oxide abrasive powders as far as I know are very stable.

I understand Aluminium Oxide Al2Ois the product of the thermite reaction and not the fuel.

I don't mean this aggressively... but do you have any evidence to the contrary? I would be very interested to see it.

Alan

MSDS-AluminiumOxideAbrasiveGrain.pdf

 

 

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18 minutes ago, bigb said:

Very interesting information. That is actually one of the hypothesis regarding the Hindenburg disaster.

thermite.PNG

The theory has been going around for a couple decades but it's not born out be the evidence. The movie footage doesn't show anything in the spectra of a thermite reaction. The iron oxide and aluminum powder weren't mixed in a way nor in ratios to make thermite. Lastly the laquer the metal powders were mixed with couldn't have gotten hot enough to ignite thermite if it were present.

The Mythbusters went to pretty extreme measures, electric arc IIRC, to get a "thermite" reaction and it was very short lived. Pieces of the Hindenburg's skin is still laying on the field and they couldn't get a thermite reaction from it either.

Frosty The Lucky.

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4 hours ago, ThomasPowers said:

Powdered metal does a pretty good burn just by itself.  Shoot powdered most anything oxidizable does a good job---I recall reading the TMJ manual on improvised munitions from back in the Vietnam days... 

Yeah but the metallized dope they used on the Hindenburg wasn't powder it was more like metal flake paint mixed by a more is better guy.

I read a few of those manuals but don't talk about "dust exciters" in public too often.

Frosty The Lucky.

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  • 4 months later...
On 4/20/2016 at 9:16 PM, ThomasPowers said:

Powdered metal does a pretty good burn just by itself.  Shoot powdered most anything oxidizable does a good job---

In 30+ years in my industry (honeycomb) I've seen a couple of bad ones from the aluminum dust our bandsaws produce.  

Ist was a 55gal drum of powder that had been sealed with poly sheet & tape & stored out back the shop.  The sheet allowed the barrel to get water in and made a galvanic circuit.  When the H2/O2 recombined it blew a hole about 6' deep in the caliche yard & a whole bunch of the back windows.  The plant manager wasn't happy.

2nd one was accumulated dust, rags, old airlines under a 5' x 12' 1/2"aluminum topped layout table.  Gas axe sparks set off the crap under the table & the top started melting & finally caught.  Before the guys in the shiny red trucks got it extinguished, the fire had gone through the roof 22' up.  Different plant manager, but also not happy.

Thankfully, that maintenace guy went on to another career path.

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22 hours ago, ThomasPowers said:

ever seen the remains of a RR car of scrap steel that self ignited and burned?   It's really dangerous living in an oxygen rich atmosphere!

Sounds like we need to ban either oxygen or combustion altogether - you know, for the sake of the children.

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My grandfather served in WWII as a Marine; he told me that they didn't shave, they just used a ballpeen hammer to pound the hairs in and then bit them off and spit them out...He survived Iwo Jima and at 90+ wanted to know why I wasn't going to reroof my house myself---he's come and help!

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