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

[peter fels & phoebe palmer]

On 11/2/2010 5:34 PM, Jerry Frost wrote:
> 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 once saw a muffler guy heat up an exhaust pipe with an OA torch, then 
shut off the acet and make the 360*cut with the oxy.
I tried it once and it sorta worked, no where near as neat.
> 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.
Ah, the creative process!
> 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>
You are soooo diplomatic my friend!
> 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
>>>
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