Model Forum / General / Models / August 2009

Old oil is the way to go. I've never had a fire in 30 years of 'blacking'.
Not much in the way of fumes but do it outdoors if that is your concern.
I've always done it with mineral oil. I don't know if synthetic oils
make any difference good or bad.

Bob

The hot oil method works fine but the operative word is quenching - you need
to get the hot metal under the oil surface as quickly as possible to avoid
setting fire to any vapour above it.  Make sure there's a reasonably large
volume of oil so it doesn't get hot, and have a lid or a fire blanket
available to drop on it if it should catch fire.

I've also used metalblak solutions and the process also works fine.  However
you do need to be scrupulous about cleaning the pieces and not handling them
without latex gloves if you want to get a nice smooth finish.  I find the
blacking solution a lot less exciting and there is no risk of any distortion
from heating, but it's a lot more fiddly.

In article <4d4350ec-c4a8-4515-9587-728fcff63755@d4g2000yqa.googlegroups
.com>, david.rogerson@hey.nhs.uk <david.rogerson@hey.nhs.uk> writes

Have just been experimenting in a small way with phosphate treatment.
I just left some mild steel nails in 'Jenolite'(phosphoric acid rust
treatment). I warmed the solution by standing the container in boiling
water. After a couple of hours there was a good black finish on them. I
de-watered with WD40 and then wiped with gun oil. Seems good so far.
Will be trying larger pieces of mild steel later.

mattathayde had written this in response to
http://rittercnc.com/modelengineering/Blacking-Steel-12073-.htm  :

-------------------------------------

the only issue with getting metal red hot then quenching in oil is that
you will
drastically change the temper of it, and depending on the type of steel
you
could even crack it

im not sure how "black" your going for but from my experiences with knife
making  
quenching only gives a dark gray/blue color which to me seems to be a bit
more
just from the heat.

if you want a nice dark black that will last i would look towards a
"blueing" or
parkerizing, only down fall of those is cost

-matt

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I've sucessfully used Ilford 'Paper Fixer' for steel blacking. 10%
solution with water, bring to just boiling in a pyrex jug or bowl in a
pan of water and immerse the steel object. Works a treat and is cheap
and innocuous as far as I'm aware. When black rinse thoroughly, dry
and oil. Do a test on a blank bit of steel to try it first.

AWEM

On 18 Aug, 09:25, "david.roger...@hey.nhs.uk"
<david.roger...@hey.nhs.uk> wrote:

Thanks to everyone lots to try and think about, will try the Carr's
when it arrives and then if not happy move onto the photo fixer.
Thanks again.
Dave

If you have a gunsmiths nearby, try a bottle of gun blueing gel.
It's a cold treatment based on selenium salts and will require careful
cleaning of the parts to get an even surface effect.
I use a small brush to apply it and if necessary the process can be
repeated to improve the blackening.
After washing the parts, apply some black shoe polish to the steel and
buff to a nice shine.
The depth of blackening is not great but it's very easy to get a good
effect.