Author Topic: Black oxide - how/where?  (Read 12931 times)

Offline AdeV

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Black oxide - how/where?
« on: August 12, 2010, 12:16:11 PM »
Whilst looking for a sensible way to black-oxide finish a steel part, found a link to some excellent sounding stuff called Insta-Blak (http://www.epi.com/pages/steel-black-oxide-2).

Even better, they offer a sample pack for just $37.50 + S&H, sounds ideal  :D

Unfortunately, S&H to the UK costs $300!!!  :(

EPI don't have any UK distributors, nor any European distributors who take sufficient range of chemicals to make up a sample kit.

Stymied!

So, fellow Brits, what chemicals/processes do you use to make that black-oxide finish? And do they create a coating that doesn't rub off, as the EPI one claims?
Cheers!
Ade.
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Offline Bluechip

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Re: Black oxide - how/where?
« Reply #1 on: August 12, 2010, 02:13:49 PM »
Adev

I think this is what a friend used, .... the Pixel-Plus seems familiar ..

http://www.black-it.co.uk/

Never used it myself. IIRC he used it on a very nice Stephanie ... if I'm right, some of it gives a very attractive matt finish which looks really well with brass.

Snuffed it unfortunately, about 8-9 yrs ago.

(Him, not me  :scratch:  )

Dave BC
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Offline DMIOM

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Re: Black oxide - how/where?
« Reply #2 on: August 12, 2010, 04:56:17 PM »
So, fellow Brits, what chemicals/processes do you use to make that black-oxide finish? And do they create a coating that doesn't rub off, as the EPI one claims?

Well, I don't know how it compares to the EPI one etc., but I have done a few bits with Caswell UK's Cold-ox and it has stood up OK for me.

Dave

Offline cidrontmg

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Re: Black oxide - how/where?
« Reply #3 on: August 12, 2010, 05:00:20 PM »
Iīve used Tectrate, a long time ago. Bought it from
http://www.modelmakingsupplies.co.uk/taps---dies.htm
about 1/3 down the page.
Olli
Penafiel
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Offline AdeV

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Re: Black oxide - how/where?
« Reply #4 on: August 12, 2010, 08:11:57 PM »
Excellent, thanks chaps, that's 3 suppliers of the very stuff. I must have lost my Google mojo (Goojo?) this evening...  :scratch:


Well, I don't know how it compares to the EPI one etc.


Ah, sorry, that was me being unclear; I was hoping to find one (or more) UK alternatives which at least claimed the same properties (won't rub off, reasonably anti-corrosion). I've not seen much about rubbing off, but they all seem to follow the same principles, and they all seem to involve Selenium, so I'm guessing they're basically the same thing... I've a way to go yet before I'm at the stage of needing to use it, but it's good to know it's available for reasonable money in the UK.
Cheers!
Ade.
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Offline Ned Ludd

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Re: Black oxide - how/where?
« Reply #5 on: August 13, 2010, 09:25:18 AM »
Hi AdeV,
What about trying Delway, they do "metalblak".
Thinking of Delway, have you dissolved your broken tap yet?
Ned
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Offline winklmj

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Re: Black oxide - how/where?
« Reply #6 on: August 13, 2010, 11:00:30 AM »
Heat and used motor oil. I've heard it mentioned many times. Some heat then quench. Some dunk then heat. Here's a topic:

http://www.homemodelenginemachinist.com/index.php?topic=3766.0

Mike

Offline AdeV

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Re: Black oxide - how/where?
« Reply #7 on: August 13, 2010, 11:23:52 AM »
Ned - I hadn't thought of him, no... I'd not managed to get hold of him for the cartridge cleaner, then the nitric acid arrived from another source so I didn't try again...

Following winklmj's links (ta!) I found a copy of the Delway price list... so far, the Cold-ox kit looks like the lowest cost for maximum chemicals :)
Cheers!
Ade.
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Offline stovebolt

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Re: Black oxide - how/where?
« Reply #8 on: August 14, 2010, 05:54:15 PM »
Ade, there is an old process called rust bluing,  until the use of caustic salts for gun bluing, they simply let the clean steel rust, then boil in water, after which "card"  it,  which means buff it with a fine stainless steel wire wheel or by hand with 0000 steel wool. To test this I'm sure you have some rusted steel about, all you have to do is boil it.  As for rust inhibiting, I'm sure it still requires a coat of oil. 

 ( caution, this is a gun site, in case you have any big brother problems) 

http://www.winrest.com/blueinstructions.html

After reading about this I remembered doing some electrolytic rust removal, so I tried it, I think the finished product is pretty much the same,

     

Offline andyf

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Re: Black oxide - how/where?
« Reply #9 on: August 14, 2010, 08:31:47 PM »
Ade, you don't say what your "steel part" is.  If it's your QCTP, my quick and dirty approach would be to heat it until it just begins to glow dark red, then chuck it into a can of old engine oil (from a diesel for preference)*. Have something available to put over the can to smother any flames, and let the component cool down before you fish it out, or it might ignite the surface oil. 

Best done outdoors, obviously, and at dead of night, too, so you can judge when it "just begins to glow dark red".

* I have never tried it, but some swear by vegetable cooking oil.

Andy
 
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline AdeV

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Re: Black oxide - how/where?
« Reply #10 on: August 15, 2010, 01:42:18 AM »
Hi Andy,

The part is, as you surmise, my QCTP... the only problem I have with heating it is, I don't have any means of heating such a big lump of metal with any hope of keeping it even close to a uniform temperature, not to dull red at any rate. I can get it up to a couple of hundred degrees C in a toaster oven, but I suspect that won't be enough.... hence the idea of cold blacking which, in conjunction with some displacing oil, seems to do a reasonable job of rustproofing whilst making the part look pretty too...
Cheers!
Ade.
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Offline Artie

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Re: Black oxide - how/where?
« Reply #11 on: August 15, 2010, 10:52:06 AM »
Hi Ade, I used commercial gun blue. A bottle which I have used for 6 tool holders still has a useful amount in it, http://madmodder.net/index.php?topic=3206.0 I dont know if this is an Aussie brand (I suspect not given the bottle size in ounces), probably different over there. Ends up looking like the bought stuff over time, it gets darker over several days. I heated this til it was just too hot to handle comfortably, certainly not HOT, then blued.....

The bottle pictured in the link cost $14 Aus (approx 6 pounds??)

Good luck.

Rob
South Wales, wait...NEW South Wales... Batemans Bay.

Offline No1_sonuk

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Re: Black oxide - how/where?
« Reply #12 on: August 24, 2010, 08:01:42 AM »
Ade, there is an old process called rust bluing,  until the use of caustic salts for gun bluing, they simply let the clean steel rust, then boil in water, after which "card"  it,  which means buff it with a fine stainless steel wire wheel or by hand with 0000 steel wool. To test this I'm sure you have some rusted steel about, all you have to do is boil it.  As for rust inhibiting, I'm sure it still requires a coat of oil. 
There was an item about a shotgun in an episode of "How Stuff's Made" on TV a while ago.
In that, they boiled the barrel in "salt water" (not sure if it was really the "caustic salts" you mentioned) to rust it, rinsed in fresh water to stop the rusting, then soaked it in oil.  As long as it's kept oiled, it won't rust.

Offline AdeV

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Re: Black oxide - how/where?
« Reply #13 on: September 12, 2010, 05:51:57 PM »
I eventually bought the 4-litre kit from Caswell Europe, and earlier today blacked up the body of my QCTP:



Although it didn't seem to be working terribly well at the time, the finish has actually come out very well. I've not tried scratching it to see how deep it is - I'm sure it'll scratch over time - but it certainly looks the part.
Cheers!
Ade.
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Offline cidrontmg

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Re: Black oxide - how/where?
« Reply #14 on: September 12, 2010, 06:06:49 PM »
It certainly does. My Tectrated surfaces were/are quite scratch-proof. I donīt remember how long ago I blackened some tools, but many years ago (>10). They still look excellent. Just occasional wipe with an oily rag, thatīs all. Outside corners are vulnerable, as you might expect, but from a flat surface, it takes an effort to remove the oxide.
Olli
Penafiel
Portugal

Offline owdbob

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Re: Black oxide - how/where?
« Reply #15 on: October 01, 2010, 04:54:12 AM »
Hi ,The October edition of Model Engineers Workshop has an article on "Home Metal Blacking". It has details and a pictorial run through. The supplier mentioned was//Delway Technical Services,192  Seabank Road, New Brighton, Wallasey, Merseyside, L455AG :tel 01516393201.  The author gave his email as " terryowens99@tiscali.co.uk"  I am very new to this hobby to web-forums,so, I hope this information is relevant and that I have not broken any rules.( I should be known as "Bob the bewildered" 

Offline sub-xtx

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Re: Black oxide - how/where?
« Reply #16 on: October 10, 2010, 01:48:12 PM »
Hi guys, sorry for my English. :bang:
You can try to black iron with an old method:
#1 part (i.e. 20grams) of Sodium Hydride
#2 parts (i.e. 40 grams) of Potassium Nitrate
#3 parts (i.e. 60 grams) of water
warm until boiling e put your piece in, let it few minuts checking for your wanted color.
PAY ATTENTION using Sodium Hydride!!!!!!! It's very caustic.
Protect yourself with gloves, eye-glasses,etc.
Good luck.
Osvaldo

Offline rleete

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Re: Black oxide - how/where?
« Reply #17 on: October 10, 2010, 02:28:01 PM »
I recently tried a method I read about here or another forum.  Take your part, and heat it with a torch (I used plain old propane) until it starts to turn blue.  Takes only about a minute.  Then, dunk it into used motor oil (dead dinosaurs, not synthetic!) for a few seconds.  Do this outdoors, it will smoke and stink.  Repeat the heat and dunk  - no color change to guide you, so just heat it until you've burned off all the oil, and then keep going for another 30 seconds or so.  Try to heat it evenly.  Dunk a second time, and swirl it around under the oil.  Comes out looking a nice matt black.  Finish depends on the original surface finish of the part, but I just hit this one with some sandpaper (220 grit?), and it was not buffed or polished.

Here's a pin I made to repair a coworker's airsoft BB gun:
Creating scrap, one part at a time

Offline Corvus corax

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Re: Black oxide - how/where?
« Reply #18 on: October 29, 2010, 08:57:38 AM »
It doesn't have to be motor oil. Linseed oil, bees wax, canola oil and peanut oil all work. It's effectively the same method that is used when one seasons a wok or skillet.

You can either paint the oil on first and then heat it or heat it first doesn't matter.

The part doesn't have to be heated till red hot and then quenched. One just needs it hot enough to open the pores of the metal.

Linseed oil was the traditional method to protect wrought iron. Some smiths also mixed Linseed oil and Bees wax.
I 've done small firearm parts with Linseed oil and they came out looking pretty good. Just repeat multiple times to deepen the colour.

As to the cold blues: Birchwood Casey "Super Blue" works well.
A couple of years back I stripped down an old Enfield No1 and reblued it completely with that stuff.
It came out very nicely. The finish isn't quite as hard wearing as a proper rust blue or for that matter the aforementioned oil blackening.

Just don't use it on surfaces that will see a lot of wear. I recently blued a rest for my offhand grinder with it and while it works better than other cold blues it is rubbing off.

Offline bry1975

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Re: Black oxide - how/where?
« Reply #19 on: November 05, 2010, 07:00:29 PM »
Any of you chaps send out parts to be PVD or DLC'D?  you know like the drill bit coatings.

Bry