"Hand-blackened" steel

[peterbange]

Hi ...

I'm "borrowing" the design of a welded steel frame table base that I found on the internet (steel table 1 on welcome to henrybuilt (http://www.henrybuilt.com)). They say the finish is "hand-blackened". My finish table size will be 2.7 x 1.1.

I've spent a lot of time looking at black-oxide finishes (hot & cold), parkerising, bluing etc. but none of these finishes seem appropriate to my situation (e.g. size of the pieces involved, DIY etc..).

Does anybody have ideas for what a "hand-blackened" finish may be? I've seen some reference to a "phosphoric" finish but no details.

Thanks in advance.

peter

[12teethperinch]

Hi
I worked for a contemporary furniture design company doing product development for a few years. They had some clients in the states that we sold some product to that wanted us to do a hand blackened finish, they sent us a table from one of there other suppliers that had this "hand blackened finish" I did a lot of research into trying to do a finish but for our smaller scale there just wasn't anything that didn't require a large outlay in equipment. I did do a few prototypes that were blackened with the stuff for blackening the solder on stained glass The name of it escapes me a the moment sulfate something or another. It did an OK job but th work had to be very clean not even a finger print and if you were brushing it was hard to keep the finish even, you still had to wax it or otherwise coat it to keep it from rusting. I would go with a nice powder coat if I were you. Good luck
Darrell

[Claw Hama]

Depends on the finish you're after but stove black/pot belly black works well.

[neksmerj]

The question of blackening steel, especially machine parts, comes up often, but without an answer.

Surely someone out there knows of a home brew solution that really works. I've tried bottles of gun blue, and phosphoric acid, with little success.

Surely we must have some industrial chemists as members.

Ken

[Old Hilly]

Well, I've been using an automotive "etch primer" for gun barrels and actions lately. Much better than any of the "cold blue" solutions and fairly rust resistant. It gives a matte finish similar to Parkerising and has a very slight blue-grey look to it rather than a deep, pure black.
Havn't had much luck with any of the cold blues :~ but Birchwood-Casey is advertising a spray-on, water clean-up air cure epoxy gun finish that sounds pretty good. I think I will give it a go when I am almost finished this can of etch primer.
Dennis

[Woodlee]

Have a look at Caswells au. or Janes Kits website for chemical finishes on steel stainless and other alloys.
All the blackening /blueing solutions I know of use chemicals that will bring attention by the authorities when you try and purchase them .
I've basically given up trying home brews and will purchase a kit from Caswell when I get the urge .
I've been using KleenBore Black Magic gun blue /black for doing small tools .I've found by experience that this is the best available here in Australia.
Kev.

[joe greiner]

Transcribed from the Handbook of Chemistry and Physics, 41st edition, 1959-1960, p. 3281:

"LABORATORY ARTS AND RECIPES
Many of the following recipes have been contributed by users of the Handbook. To those who have cooperated in this way we extend our grateful acknowledgment.

BLUING STEEL AND IRON
The metal is cleaned with a potassium bichromate-sulfuric acid mixture, then washed with ammonium hydroxide and rubbed dry. Apply ammonium polysulfide until the desired depth of color is obtained, allowing the object to dry after each application and rubbing briskly with soft clean cloth. The result is a deep blue which may be made very nearly black by repeated applications. Rubbing with boiled linseed oil will deepen this color more. The finish thus obtained is very resistant to oxidation."

The text is silent on proportions and concentrations. Nomenclature may also be antique. I haven't tried it myself, but provide it for your consideration. Forum member Gil Jones is a gunsmith (no longer practicing), and may be able to provide more up-to-date suggestions.

Cheers,
Joe

[Claw Hama]

Hi Joe can you check or confirm that that is potasium bichromate or dichromate?

It's ok I think it is the same, potasium chromate used for staining wood etc.

[peterbange]

Thanks for the ideas. I've been researching further and am leaning towards applying more of a artists patina followed by a wax coating:

patina (brown & black) (http://artenero.com.au/91_supplement/pat1_11.html)
PATINAS FOR STEEL / IRON (http://shop.surfinchemical.com/PATINAS-FOR-STEEL-IRON_c8.htm)
http://www.artmetal.com/project/TOC/finishes/ferrous/patinas.html
Traditional Black Patinas - Finishes (http://www.sculptnouveau.com/Details.cfm?ProdID=78&category=6)
Barnes Products Pty Ltd (http://www.barnes.com.au/catalog/index.php?cPath=56_60)
Wax Finish (http://www.appaltree.net/aba/education/technical/finishes/wax%20finish.htm)

Or maybe trying this:
Blackening steel. 3.
For a brown-black finish.
First brush the clean surface with a copper-sulphate solution. Wait a few
minutes then wipe dry, and then apply a solution of ammonium sulphide. After
30 seconds, dry with a clean cloth.

None of these finishes are likely to be as durable as traditional black oxide etc..., but I'm only after a decorative finish that will be indoors all the time anyway.

Thanks again.

Peter

[soundman]

There are a lot of those old finishes that are either not very durable or require use of chemicals we are no longer happy handing.

The OHS outlook overseas may not be as ... um..."up to date" as we are.

Black etching primer with black QD enamel with matting agent I have found to be good a durable and relativly easy to apply.

If you want it rough and coarse.....run the product with a minimum of thinner if any at all....and.. keep the air supply as low as you can and still reliably atomise.....a dry spray.

There are some textured black paints out there too

I'll have a look in one of my old metalwork texts..it has heaps of recipies in the back.

cheers

[Gil Jones]

When I performed hot bluing on guns, this is pretty much what I did (and I used Brownells bluing salts) GunTech : Bluing The Traditional, Hot Salts Way - World's Largest Supplier of Firearm Accessories, Gun Parts and Gunsmithing Tools (http://www.brownells.com/.aspx/lid=11044/guntechdetail/Bluing_The_Traditional__Hot_Salts_Way)

The most labor is in the polishing, which I did using a 1hp Baldor 10" dual shaft buffer (which I still use on woodturnings) BALDOR ELECTRIC : 1 HP 1800 RPM 7/8" Arbor, 30" Shaft-Extends 7 3/16" (089-407-000) - World's Largest Supplier of Firearm Accessories, Gun Parts and Gunsmithing Tools (http://www.brownells.com/.aspx/sid=5264/pid=24831/sku/1_HP_1800_RPM) _7_8__Arbor__30__Shaft_Extends_7_3_16

I was not fond of cold bluing, especially the ones with selenium in them as the metal “stinks” afterward.
The old plum brown finish used in the “old days” on muzzleloaders, if done properly, is beautiful, and much better protection than hot bluing. It is a fine grain, controlled rust surface treatment.

Birchwood Casey sells a plum brown solution that works well. Birchwood (http://www.birchwoodcasey.com/sport/blueing_index.asp?categoryID=1&subcat=5&prodcat=73)

Here are some interesting articles on bluing/browning:
Bluing (steel) - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Bluing_%28steel%29)

RugerForum.com :: View topic - Rust Browning finish? (http://www.rugerforum.com/phpBB/viewtopic.php?t=72836&view=next&sid=e0aee7c5620e93b76d8518b4d80936e8)

Bluing to Browning - Alaska Outdoors Forums (http://forums.outdoorsdirectory.com/showthread.php?t=51963)

If you want dark steel legs on that table, why not just apply a good polyurethane paint over a primer. Good luck with it.

Cheers,

Gil Jones

[joe greiner]

Hi Joe can you check or confirm that that is potasium bichromate or dichromate?

It's ok I think it is the same, potasium chromate used for staining wood etc.

"bichromate" is the term in the text. I think "bi-" and "di-" are substantially the same. I'm not a chemist, BTW, but my dictionary states (for chemistry) "bi-" a. An element of group in twice the proportion necessary for stability; for example sodium bicarbonate. b. Of organic compounds, a double radical; for example bitartrate. And "di-" Having two atoms, molecules, or radicals; for example diacetylmorphine.

The only difference seems to be that "bi-" is from Latin, and "di-" is from Greek.

Thanks for jumping in, Gil.

Cheers,
Joe

[Woodlee]

Gil ,
Brownells is not available here in Oz and they wont ship it out here for obvious reasons .


Kev.

[Gil Jones]

Hey, Kev,
Hot bluing salts is a strong oxidizer, so it falls into restricted shipping rules (laws), not to mention being very careful during use. There must be some gunsmiths in Australia; after all, y'all had plenty of weapons before your dear politicians took them from you (bad idea!!).
As for 'browning", a bit of heat/humidity and several layers of fine (controlled) rust is easily doable, and does not require hazardous chemicals.
Still, for table legs, a good paint should be enough.
Cheers,
Gil