Chemically blackening brass

[Dralowid]

Here's a question...

I have a black II with a baseplate that looks as if it has been painted in tar...it looks bad, not nice, just plain bad.

It will be an easy job to strip the baseplate, fingernail will do the job, but what then? A repaint would look way too much and the less I put on it the better.

I propose to have a go at blackening the brass. Has anyone done this and if so, with what and how?

As to the lettering, I'm not sure. I want to try the trick of applying heat from behind to see if it can make the Woods Metal bubble up and brighten...but that might mess up the blackened surface...and I am not 100% sure if all cameras had Woods Metal on the baseplate. We shall see when the baseplate is stripped, it is all painted over.

So time for some experiments. The camera is a 1930 I converted to II, its a great user but leaves the user with flecks of paint on their hands...

Michael

 

[rodt16s]

Would it require Cu plating first..? I guess that may depend on the Cu content of the Brass.
Could always take it to a local electroplater and go for Black Ni.

 

[Murray Kelly]

I remember blackening brass buttons and buckles but all I know is that it was a sulphide of some sort. Google that.

 

[StaaleS]

The model engineering community does this, a lot. Chemicals are available over the shelf (or via the internet, at least) that will blacken brass with ease... here is a link to one retailer that I know of:

http://www.chronos.ltd.uk/acatalog/Engineering_Menu_Carrs_Metalblacking_Products_289.html

(http://tinyurl.com/c45oagq)

The product in this case is "Carr's Brass Black". I have used this with success in modelbuilding for things like brass ship's guns and steering wheels. I first dunked the item in question in Carr's Acidip, then the Brass Black, then Electrofix to coat the part but this last step is probably not necessary for a baseplate. Rinse in water and dry the piece between each step. Because the baseplate is so big you may need more than one bottle to cover it all (it is not something you paint on, but something you dip the part in question into). Fortunately the cost of a bottle is not preposterous 🙂 Let it "soak" until it has the proper colour, then take out and rinse well with water. Do not leave it in too long.

"Gun-blue", for blackening iron, can work on brass and is more readily available but I've found it to be too quick-working and hard to control.

Edit: Oh, and the part you wish to blacken must be clean, clean, clean. Really clean. No fingerprints or grease of any kind on it.

 

[dannyt]

Birchwood Casey's Brass-Black will do the trick

 

[Dralowid]

Thanks guys, experiments will soon start. I guess within reason that one can re-use the solution so long as it hasn't become too 'tired'?

Michael

 

[StaaleS]

Thanks guys, experiments will soon start. I guess within reason that one can re-use the solution so long as it hasn't become too 'tired'?

Michael

Yes, it is reuseable, within reason. Ideally, the brass should be "fresh off the lathe" so to speak - immediately beforehand, rub it thoroughly all over with emery paper or some such to remove the oxidization that inevitably covers it. Then rinse to remove fat and grease.

Practice on some scrap brass first. (I don't really have to say that, do I?)

 

[Dez]

I have found that gun blueing also works on brass, although not as well as on steel. The stuff I tried was also made by Birchwood casey, called Super Blue.
Does anyone know what these chemicals are? I had assumed that gun blueing was ferric chloride, but I'm not sure/ I would like to understand the reaction.

The company seems to be located in Eden Prairie, MN, which is about two miles away from me.

Cheers,
Dez

 

[wolves3012]

I have found that gun blueing also works on brass, although not as well as on steel. The stuff I tried was also made by Birchwood casey, called Super Blue.
Does anyone know what these chemicals are? I had assumed that gun blueing was ferric chloride, but I'm not sure/ I would like to understand the reaction.

The company seems to be located in Eden Prairie, MN, which is about two miles away from me.

Cheers,
Dez

Ferric chloride wouldn't react with the iron in steel. Here's a decent article on steel bluing:

http://en.wikipedia.org/wiki/Bluing_(steel)

 

[Dez]

Thanks for the interesting link. the stuff I have must be the selenium version. I wonder what the reaction is with brass..............

Cheers,
Dez

 

[V-12]

As to the lettering, I'm not sure. I want to try the trick of applying heat from behind to see if it can make the Woods Metal bubble up and brighten...

Beware of heating brass, you will anneal it making it soft even at relatively low temperatures. The only way to harden brass up again after annealing it is to work harden it, which you can't do with a baseplate.

 

[mdarnton]

http://www.ganoksin.com/borisat/nenam/liver_of_sulfur.htm