[TheForge] Putting an oxide finish on mild steel?

[Peter Fels And Phoebe Palmer]

Hi Bill:
In my experience, the more effective the sealer is, the more it damps 
the ephemeral surface oxide colors.
Sure is purdy...for a while.
I've concluded that , this being art, the only reasonable thing to tell 
the inquiring client is than when the finish fades to rust, they are to 
humbly return the piece and buy a new replacement....keep a straight 
face.....
Re copper/steel interface.. there is an old smithing tradition of copper 
brazing in a cola fire...have' to guess the difference is the amount of 
oxidation on the copper when both reach critical temperature. I'd also 
guess the copper dam , being so conductive just siphons enough heat from 
the steel at the edge of the weld, not to reach liquidus.
  We are fogged in solid...must think it's summer time outside 
already...Pete F

Woolley wrote:
> Greetings,
> 
> When I discovered how beautiful an effect I could get with an acetylene
> torch on polished (it must be polished, bright, as in no mill scale, not
> just wire brushed) mild steel ( purples,greens blues) I thought I was going
> to be able to use this finish for all kinds of decorative stuff ( panels,
> furniture) until I tried to fix it.  I found that if I sprayed a lacquer or
> any kind of clear it would go like an ice blue color time and again. I have
> managed to preserve the oxide colors with oils but these never dry so the
> pieces can't  really be handled too well (not a good selling point for
> furniture).  I have pretty much abandoned this finish. My two cents.
> 
> Regareds,
> Bill Woolley
> 
> 
> ----- Original Message -----
> From: "Justin Fellenz" <sunironworks at yahoo.com>
> To: "Sponsored by ABANA" <theforge at mailman.qth.net>
> Sent: Saturday, March 12, 2005 7:59 PM
> Subject: Re: [TheForge] Putting an oxide finish on mild steel?
> 
> 
> 
>>I've been playing with this effect on the damascus wedding ring I made
>>myself. I found that if I heat it over the gas stove to where I just
>>see it darken and then take it off and let it cool slowly in air, I get
>>a progressively darker finish--it seems that being in the flame (I
>>guess like in a gas-welding environment) keeps the metal protected
>>somewhat..once I take it out of the flame the oxides seem to get darker
>>over time than they do in the flame. I haven't been able to come up
>>with anything reproducible either, but I haven't tried--I'm just
>>noodling. Maybe a known time in a known flame and then a known cooling
>>time would yeild predictable results. It also seems to work better the
>>more polished the surface.
>>
>>Justin.
>>
>>--- Steve Smith <sos at alum.mit.edu> wrote:
>>
>>>
>>>Aaron Stavens wrote:
>>>
>>>
>>>>I had another different piece of sheet steel I had welded on with
>>>
>>>E6013.
>>>
>>>>I had baked it in my kitchen oven and, unintentionally, it acquired
>>>
>>>a
>>>
>>>>dark blue color with purple and copper highlights. There is also a
>>>
>>>nice
>>>
>>>>iridescence in places. My friend saw this and liked it. So, I'm
>>>
>>>trying
>>>
>>>>to achieve a similar effect on the bracket.
>>>>
>>>>I figured I would buff the bracket with a wire wheel and bake it in
>>>
>>>the
>>>
>>>>oven like I did with the previous piece. The baking didn't go so
>>>
>>>well.
>>>
>>>>All I could achieve was a very light translucent blue even after
>>>
>>>hours
>>>
>>>>in the oven. I assume my oven simply isn't hot enough, but I'm
>>>
>>>already
>>>
>>>>running it at the maximum of 550F. I also tried heating the bracket
>>>
>>>with
>>>
>>>>my welding torch. I achieved a whole rainbow of colors, but I
>>>
>>>couldn't
>>>
>>>>seem to control the colors I achieved.
>>>
>>>You're right in describing this as an oxide finish. What happens is
>>>if
>>>you have a thin enough layer of oxide, light hitting the surface will
>>>
>>>interfere with itself (this thin the oxide is essentially
>>>transparent).
>>>This reinforces some wavelengths and reduces others, which leads to
>>>colors.
>>>
>>>I think what you have might be too thick a layer of oxide, giving you
>>>
>>>the translucent blue. Try running it at several lower temperatures
>>>(400F? 450F?) and see what happens. Make up some test pieces and take
>>>
>>>them out of the oven at different times.
>>>
>>>You might also try heating one end of a shiny piece of metal with a
>>>torch. The colors "run" along the rest of the piece really quickly
>>>when
>>>you get to the right temperature. It may be tricky to control, even
>>>in
>>>an oven.
>>>
>>>Steve
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>>>
>>>
>>
>>_______________________________________________
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>>
> 
> 
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