"Blacking" Steel

I ahve just finished the Hemingway, Trent Pinion mill and have taken it all apart to finish the parts. The steel parts I would like to
black. The instructions recomend heating to red hot and plunging in old oil, which I dont like the sound of. I have found Carr's blacking but have heard it can be patchy, Any experiance out there? Dave
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snipped-for-privacy@hey.nhs.uk wrote:

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
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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.
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In article < snipped-for-privacy@d4g2000yqa.googlegroups

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.
--
Chris Holford

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mattathayde had written this in response to http://polytechforum.com/modelengineering/blacking-steel-12073-.htm :
------------------------------------- snipped-for-privacy@hey.nhs.uk wrote:

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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blacking
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
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I use Kodak Acid Fixer the same way! It works! Don't make the solution too strong though.
Steve R.
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Steve R. stelde de volgende uitleg voor :

Thanks, this is completely new to me. Can you elaborate on this? Like what form of fixer did you use, powder or liquid. And if liquid, what was the original dilution? How important is the amount of water added and how does it affect the end result. Best regards, Dirk
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taken
to
in
10%
in a

cheap
dry
solution too

Like
what
added
I bought a bottle of 'Ilford paper fixer', for 4.99 which is a liquid. Diluted it 10:1 with water, brought it to simmering temperature in a pyrex jug, and immersed things in it until they were the darkness I wanted. My initial experiments were carried out with a series of bright finish 4" steel nails. Remeber to make sure your 'objects' are chemically clean so the liquid 'wets' them uniformly.
AWEM
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Andrew Mawson formuleerde de vraag :

Thanks again! I will dig up my dark room to see if there is any left ;-)
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On 18 Aug, 09:25, " snipped-for-privacy@hey.nhs.uk"

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
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The time honoured way is to heat up to cherry red and plunge into a copper kettle of virgins blood, however we all know how hard it is to get a copper kettle nowadays.
John s.
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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.
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