[TheForge] why doesn't cast iron oxidize and burn in the same way?(was: oil/wax finish, blackened steel)

[Jerry Frost]

Yes, no matter how fast it's all oxidization. A cutting torch depends on the 
oxidization temp of the steel being much higher than it's melting temp. You 
can actually "see" rusting iron with a sensitive IR scope. It'll also show 
up on em sensors too. Neat stuff chemistry and physics.

Dad used to talk about torches they used during WWII that you could shut off 
the acet once the steel began cutting and the burning steel did all the 
work. I've never heard of it anywhere else so can't say how true it is. Dad 
was never a fabricator, iron worker, etc. Machinist and metal spinner all 
the way so there's no telling what he saw or thought he saw, heard, etc.

I like the table analogy Andy. I think it's much more flattering than the 
digestive track analogy I most often think applies. Swallow another one and 
crap out any old something in return.

Yeah Pete, I sure can use the tree as an excuse. My old excuse was hitting 
40 but got married and there went THAT one. <sigh>

Jer
----- Original Message ----- 
From: "peter fels & phoebe palmer" <artgawk at thegrid.net>
To: "Blacksmithing List Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Tuesday, November 02, 2010 7:54 PM
Subject: Re: [TheForge] why doesn't cast iron oxidize and burn in the same 
way?(was: oil/wax finish, blackened steel)


> If you put a red hot piece of iron in an oxy atmosphere, it'll burn and
> produce heat in the process.
> The rust is a different molecular form of oxidized iron than slag.
> Once iron starts burning, the heat produced sustains the continued cut
> under the oxy jet and the pressure blows the slag and some melted iron
> out the bottom.
>
> On 11/2/2010 12:04 PM, Andy Gladish wrote:
>> It ain't all the tree's fault. I often compare my mind to a very small
>> table- or any horizontal surface in my shop- it's completely full of 
>> stuff
>> so when you put something on one side you automatically push something 
>> off
>> the other side.
>> I still don't really "get" what's going on with the torch cutting, is it
>> correct to think of it as a hyper-fast rusting process? It seems very
>> different, since rust doesn't produce anything much like slag..
>>
>> -----Original Message-----
>> From: Jerry Frost
>>
>> ...Funny how someone with a decent size chunk of gray matter turned to 
>> rust
>> remembers the darndest things. This bit came right to mind when you asked
>> Andy but I can't recall one of my niece's name for nothing. Damn TREE!
>>
>> Jer
>>