Blacken Brass

[sailor jim]

Tried Liver of Sulphur as directed. Went on a few sites  & this stuff seemed to be the right stuff.

It wasn't!!! Worked great on a piece of flat stock, that I do not think was all brass, Said to myself this stuff is great. Tried the cannons & some other fittings . NOTHING. I know they have blacking that everyone says works but the company is not selling it anymore. Any Suggestions?

[RichardG]

Amazon have Birchwood Casey Brass Black http://www.amazon.com/Birchwood-Casey-Brass-Touch-Up-3-Ounce/dp/B0000C514O/&qid=1425948821

 

Richard.

[hornet]

Have a look at this thread Sailor Jim

 

http://modelshipworld.com/index.php/topic/9781-blackening-brass-problem/

[gjdale]

Jim,

 

Liver of Sulphur (LoS) will not blacken brass. It is great for using on copper, and has the distinct advantage of being able to be applied in situ on the model, with the excess being washed off and not effecting the surrounding timber.

 

For brass you need a different solution. Birchwood Casey Brass Black is a good choice for this and can be found at most gunsmith supply shops. This, however, cannot be applied in situ on the model.

 

For either brass or copper, you need to ensure that any protective film is removed (fine sandpaper is good for this) and that the parts are thoroughly cleaned before blackening using either white vinegar (muriatic acid), or acetone.

[Canute]

Jim, if you use acetone (readily available at the big box hardware places) be advised to use breathing protection and rubber gloves. High concentrations of acetone are hazardous, whether thru breathing or on your hands. I recommend using vinegar to clean your parts.

This thread goes through the whole process: http://modelshipworld.com/index.php/topic/6977-the-blacken-it-trials/  Read through itbefore you decide which products to use.

Edited March 10, 2015 by Canute

[wq3296]

Greetings Jim,

 

Forget all this baloney - get some flat black spray paint. It works every time.

 

wq3296 

[Keith_W]

For either brass or copper, you need to ensure that any protective film is removed (fine sandpaper is good for this) and that the parts are thoroughly cleaned before blackening using either white vinegar (muriatic acid), or acetone.

 

Can someone correct me on this? I thought that "white vinegar" is acetic acid (CH3COOH) whilst "muriatic acid" is hydrochloric acid (HCl)?

[mtdoramike]

Birchwood Casey is what I use as well and it works great.

Edited March 10, 2015 by mtdoramike

[hornet]

Greetings Jim,

 

Forget all this baloney - get some flat black spray paint. It works every time.

 

wq3296

 

For larger areas this may have some merit. However for smaller one I think that blackening is the way to go. I use Admiralty Matt Metal Black (acrylic) on components which fail to blacken using Birchwood Casey - Take a look at Danny's cannon in the link on my last post in this thread. As he says, painting is unlikely to produce as good a result as blackening.

[gjdale]

Can someone correct me on this? I thought that "white vinegar" is acetic acid (CH3COOH) whilst "muriatic acid" is hydrochloric acid (HCl)?

Keith,

 

I'm no expert and would be happy to stand corrected on this.

[Modeler12]

Can someone correct me on this? I thought that "white vinegar" is acetic acid (CH3COOH) whilst "muriatic acid" is hydrochloric acid (HCl)?

You are correct, Keith.

Depending on the concentration, you don't want to use muriatic acid just to clean small parts. Of course, you can dilute it by adding some to water (and not the other way around).

[sailor jim]

Thanks to all for the reply. I did soak pcs. in white vinegar & possibly not longb enough. Think I shall try the majority of opinions & try the Casey black stuff. Pays to ask questions.

                                                                                         JIM

[dgbot]

Blackening brass is always a bit of trouble but worth it.  Paint can hide small details.

David B

[Keith_W]

You are correct, Keith.

Depending on the concentration, you don't want to use muriatic acid just to clean small parts. Of course, you can dilute it by adding some to water (and not the other way around).

 

OK, so here's another question. I am under the impression that it is dangerous to add water to concentrated sulphuric acid (H2SO4) but OK to add water to concentrated hydrochloric acid (HCl). I might have been a champ in chemistry in high school, but that was a verrrrrrrry long time ago. 

[Dan Vadas]

OK, so here's another question. I am under the impression that it is dangerous to add water to concentrated sulphuric acid (H2SO4) but OK to add water to concentrated hydrochloric acid (HCl). I might have been a champ in chemistry in high school, but that was a verrrrrrrry long time ago. 

 

Add the acid, ANY ACID including HCl, to the water - NOT the other way around. Some acids can explode if water is added to them!

 

Grant - stand corrected. Keith is right .

 

 Danny

[Jörgen]

In Sweden we use the woman name Siv to remember this. It is "syra i vatten" (acid in water) :-. If doing it in opposite way you cause a severe reaction.

 

Jörgen

Edited March 11, 2015 by Jörgen

[gjdale]

Thanks for the correction fellas.

[Modeler12]

Here is a link to another discussion about blackening metal.

http://modelshipworld.com/index.php/topic/1240-another-type-of-blackening-agent-and-some-experiments/?hl=blacken#entry23652

[usedtosail]

From Chemistry class many years ago - AAA (Always Add Acid)

[piratepete007]

From a retired chemistry teacher - ALWAYS add a concentrated acid to water. The other way around releases a large amount of heat, evaporating the water quickly and 'woosh' , out sprays the acid !!! However, diluting hydrochloric acid / mariatic acid (HCl) - which is used by brickies to clean masonary surfaces and sulfuric acid (H₂SO₄) - used in car batteries, both need to be handled OUTSIDE due to the fumes and please use protective glasses and gloves.

 

The same acid cleaning effect is generally still achieved by using acetic acid/ vinegar but just takes a little longer, so for safety, stick with that acid. It is cheap and easy to obtain. If this does not work, then as above.

 

Pete

[Modeler12]

From Chemistry class many years ago - AAA (Always Add Acid)

Are you sure it was not 'Always Add Aqua'???

[piratepete007]

That is a recipe for disaster (read my previous post). You MUST ADD THE CONCENTRATED ACID to the water to achieve a safe dilution.

 

Pete

[rckdr]

Do as you oughta. Always add acid to wata.

[dgbot]

At work several years ago they were cleaning up one of the walls and bought some muriatic acid to help. We leased the building so we had to clean it.  And one of the workers emptied it into a pail and then started filling with water.  The result was not pleasant.  He was lucky he was wearing a longsleeved shirt and goggles.  That saved his eyesight and the shirt saved him from getting splattered.  Needless to say it scared all of us especially him.  We no longer carry or use the stuff out of safety concerns.  But acid into water is the smart way and safe way.

David B

Edited May 6, 2015 by dgbot

[Landlocked123]

Hi,

 

I use distilled white vinegar as a pickle and to clean parts of flux from paste silver solder. It generally works great and even has a tendency to blacken copper (though not the solder). Being the impatient sot tham I am, is there any way to as Emeril would say "kick in it up a notch". For instance if I simmered it in a non reactive pot, would that concentrate the acetic acid? Is there something else I should use which might be a tad stronger?

 

All and any advice, suggestions, and possibly derision (in a gentle kind of way

Edited May 22, 2015 by Landlocked123

[dgbot]

One of the members in my club uses Sparex as a pickling agent and has been very hppy with the results.  The stuff can be had from any shop that sells jewelry supplies.

David B

[Dan Vadas]

Being the impatient sot tham I am, is there any way to as Emeril would say "kick in it up a notch"

 

 

I don't know, but if you're bored waiting why not tie a few ratlines or something while the stuff does it's job ?

 

 Danny

[Landlocked123]

Thanks Dan,

 

You're right, of course. It's not like there are not 47 other things to do while I wait!

 

John