I remember reading some where(RCM?) that you can make a black surface
finish on hot steel by applying oil. Anyone know what kind of oil to
use. I'm guessing it is like seasoning a cast iron frying pan.


--

Dan H.

On Fri, 24 Oct 2008 00:46:22 GMT, (dan) wrote:

I remember reading some where(RCM?) that you can make a black surface
finish on hot steel by applying oil. Anyone know what kind of oil to
use. I'm guessing it is like seasoning a cast iron frying pan.

Linseed oil works. Dab it on with a small piece of cotton rag. The
steel needs to be hot enough that the oil smokes and carbonizes while
you're applying it. Wipe off the excess when the piece is cools. A
coat of paste wax adds some protection and seems to make the finish
darker.

--
Ned Simmons

"dan" wrote in message
...
I remember reading some where(RCM?) that you can make a black surface
finish on hot steel by applying oil. Anyone know what kind of oil to
use. I'm guessing it is like seasoning a cast iron frying pan.

Does it need to be hot? I have had good success with Birchwood Casey's Gun
Bluing paste. It is an easy cold application and with the paste (rather than
the liquid) the results are less patchy. Some sort of oil/wax finish over it
is recommended.

--
Michael Koblic,
Campbell River, BC

Boiling the steel in sodium thiosulphate solution, photographers'
"hypo", also works. I just saw a reference to "black oxide" that
mentioned caustic soda at 140C.

Ned Simmons wrote:
On Fri, 24 Oct 2008 00:46:22 GMT, (dan) wrote:


I remember reading some where(RCM?) that you can make a black surface
finish on hot steel by applying oil. Anyone know what kind of oil to
use. I'm guessing it is like seasoning a cast iron frying pan.


Linseed oil works. Dab it on with a small piece of cotton rag. The
steel needs to be hot enough that the oil smokes and carbonizes while
you're applying it. Wipe off the excess when the piece is cools. A
coat of paste wax adds some protection and seems to make the finish
darker.


And if you use Linseed oil on a rag do something like burn the rag after
use. Linseed oil on rags is prone to spontaneous combustion an can light
up later on if you just chuck it in the bin.

I remember reading some where(RCM?) that you can make a black surface
finish on hot steel by applying oil. Anyone know what kind of oil to
use. I'm guessing it is like seasoning a cast iron frying pan.

Linseed oil works. Dab it on with a small piece of cotton rag. The
steel needs to be hot enough that the oil smokes and carbonizes while
you're applying it. Wipe off the excess when the piece is cools. A
coat of paste wax adds some protection and seems to make the finish
darker.

Used motor oil works too. I've quenched in this from red heat and you get a
great black finish after buffing.

Karl

"dan" wrote in message
...
I remember reading some where(RCM?) that you can make a black surface
finish on hot steel by applying oil. Anyone know what kind of oil to
use. I'm guessing it is like seasoning a cast iron frying pan.


--

Dan H.


Old-timey blacksmiths used to "blacken" iron by heating it to about dull red
and quenching it in HORSE MANURE. Then, wiping it with oil of some sort.

Yep, the softer it (the manure) was, the better. The thought then was that
the carbon that was added to the surface made it black. Blacksmith's shops
smelled that way for a reason !

The most modern method for it is used motor oil, natural, not synthetic.
Back in the days before there were so many "non-petroleum additives" to the
gasoline and the oil, it worked better.

But it still works. Hardens (depending somewhat upon the alloy) and
blackens at the same time.

Flash

"dan" wrote in message
...
I remember reading some where(RCM?) that you can make a black surface
finish on hot steel by applying oil. Anyone know what kind of oil to
use. I'm guessing it is like seasoning a cast iron frying pan.


--

Dan H.

When I was in tech. school, we had a 45 Imperial Gallon drum of motor oil
for this.


Steve R.





--
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