Author Topic: Change the 'color' of the steel on an old mill ???  (Read 1276 times)

Offline ksor

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Change the 'color' of the steel on an old mill ???
« on: November 22, 2011, 10:09:02 AM »
I have an old mill where nearly ALL the steel/cast iron witch should be "blank" has an ugly brownish color.

Take a look at the pictures in the buttom of this page: http://kelds.weebly.com/udskifte-knaelig-paring-vpf-1.html

How can I get it blank - quick and easy ?
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KSor, Denmark
Skype name: keldsor

Online BillTodd

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Re: Change the 'color' of the steel on an old mill ???
« Reply #1 on: November 22, 2011, 11:03:40 AM »
I am guessing that by 'blank'  you mean chemically blackened (stained a black colour) , sometimes called bluing (a dark blue colour)

http://en.wikipedia.org/wiki/Bluing_%28steel%29

There are several different ways to do this:

Hot bluing uses some pretty nasty chemicals, but produces a very good and durable finish

There are cold bluing pastes and salts that work reasonable well (I used a paste to do parts on my lathe)

Smaller not critical parts can be heated and quenched in used motor oil to give a black surface

Bill
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Offline ksor

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Re: Change the 'color' of the steel on an old mill ???
« Reply #2 on: November 22, 2011, 11:06:02 AM »
No, no - I can't do that with big part of my old mill - what I mean is 'blank' like (nearly) steinless steel.
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KSor, Denmark
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Offline AdeV

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Re: Change the 'color' of the steel on an old mill ???
« Reply #3 on: November 22, 2011, 11:26:42 AM »
I guess it depends on whether the brown is oil staining, or rust....

If it's oil staining, try a rag soaked in a degreaser - here in the UK that might be Gunk or Jizer. If you're careful, you could also use petrol or diesel (quite expensive though, and petrol of course is a major fume & fire hazard). Rub the affected areas until clean. Use whatever chemical works the best. If you're not going to paint them, then lightly oil the surfaces afterwards to prevent rust.

If it's rust, then you need to break out the wire brushes. Brass brushes would leave less marks than steel brushes, but will wear out much faster.
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Ade.
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Offline Lew_Merrick_PE

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Re: Change the 'color' of the steel on an old mill ???
« Reply #4 on: November 22, 2011, 11:33:31 AM »
KSor -- Basically, you polish the steel with fine abrasives to get a bright shiny surface and then you use a coating or plating to keep it that way.  At the lowest end of toughness of finish would be wax.  A well-buffed coating of wax will keep surfaces that are not subject to wear or erosion bright and shiny for an amazing amount of time.  Wax will not survive long in a bright and shiny condition if it is subjected to wear or erosion.  A waxed surface is easily recoated.  At the upper end of the toughness of finish would be hard chrome plating.  It is not all that hard to do, but it involves a number of chemicals that most localities do not want in their sewers or landfill sites and does expose the user of them to various risks.  It will survive an amazing amount of wear or erosion.  There are several choices in between these two, but this should bracket the problem for you.

Offline rleete

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Re: Change the 'color' of the steel on an old mill ???
« Reply #5 on: November 22, 2011, 12:40:41 PM »
Looks to me like it's just well impregnated with oil/grease from many years.  Throughly clean with an industrial degreaser and lots of elbow grease.  Then lightly oil.
Creating scrap, one part at a time

Online BillTodd

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Re: Change the 'color' of the steel on an old mill ???
« Reply #6 on: November 22, 2011, 02:00:14 PM »
No, no - I can't do that with big part of my old mill - what I mean is 'blank' like (nearly) steinless steel.

The word you need is 'Shiny'  (to shine)  I used WD40 and scotch bright clothes on my machines and just oil to keep them as shiny as I can ( at this time of year the dampness caused by condensation will rust things over-night :()

Be careful using any kind of abrasive on sliding or reference surfaces - sometimes it better to just gently scrape the surface with a sharp flat  blade.

Bill
Bill

Offline ksor

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Re: Change the 'color' of the steel on an old mill ???
« Reply #7 on: November 22, 2011, 06:43:22 PM »
Oh, it look's as if I have a "dirty job that has to be done" in front of me  :bang:

... and I'll need a lot of "albow greese" !  :coffee:

Thx for all the answers !
Best regards
KSor, Denmark
Skype name: keldsor