Chemical that blackens brass?

Risu said:
The Gravoxide doesn't have much info available in English, but it looks like it's the same stuff as the Birchwood Casey.
Click to expand...

Gravotech aka Gravograph aka New Hermes Engraving Machine Corp holds the trademark for Gravoxide.

GRAVOXIDE Trademark Details

Gravoxide is manufactured by Birchwood Labs aka Birchwood Casey

http://www.engravingsupplies.com.au/pdfs/gravoxide.pdf
http://hazard.com/msds/f2/ckw/ckwnv.html

I didn't look through all the info, but they do seem chemically similar. Likely same item under different names. All found in English in about 5 minutes.

Risu said:
I wanted to try the calcium carbonate in ammonia, but I haven't for the CC for sale anywhere.
Click to expand...

Now you're not even trying...

https://www.google.com/search?q=cal...L3oASF94K4CA&ved=0CAgQ_AUoAQ&biw=1280&bih=660

All that said, since you sanded, used steel wool and alcohol, I don't know why the edges aren't taking. Does the part need to be black due to oxidation? What about something like engravers enamel? Brought to you by the fine makers of Gravoxide...

Gravograph USA - Engraving Porducts / Frames and Accessories / Engraving Supplies

Just noticed that they have a note on that page that "edges of brass should not be exposed to gravoxide", Wonder what that's all about?
 
No need to get sassy. I found that first page you linked, it doesn't tell me anything useful like chemical composition. One look at the bottle and the video of how it worked and I could tell it was the same stuff as Birchwood Casey.

As for the calcium, obviously you can buy it online. When I'm experimenting with materials, though, I'd rather not pay $2 for the item and $12 for the shipping when I don't even know it will do the job. I've checked out all my local drug stores and supermarkets and haven't found any. I might end up buying some online, but since it's completely unproven it doesn't seem like the best course of action. Especially when I know there's something better out there.
 
I will admit to a bit of sass, but all any of us can go by is what you wrote.

You can buy it on Ebay for $5 and free shipping. Since you didn't mention that option, i cannot assume you looked there.

Looking forward to updates.
 
Oh, and Kevin, that's a good idea. I'll see if I can track down a legitimate gunsmith, if not I'll check a gun store, but I wouldn't have high hopes for that.
 
Three words: Brass Darkening Solution. It's exactly what you're looking for.

179201.jpg


As for Liver of Sulphur, I second that it only works on copper.
 
I take that back!
It worked VERY VERY slowly. Soaking overnight didn't do nuthin, but 2 days, well.
301lusi.jpg

So it would take how long to get it to black?
I've read somewhere a pass through muriatic acid makes this faster?
any sort of catalyst?
 
Filandrius, have you used that stuff before? If so, how quickly does it work, how durable is the finish, and how dark does it make the brass?

As mentioned before, I have brass black and it's not very good. Most effective chemical I've been able to find, but not very good.
 
Last edited by a moderator:
Yes, I've used it before. It works quickly, and the brass becomes pretty dark. Not quite black, but more like a dark grey (akin to blued steel) Check out my Obi ANH, in the first pictures I've posted, when the weathering wasn't as severe (the very first pic, as a matter of fact) The windvane and the dark part of the "neck" were darkened with Brass Darkening Solution.

http://www.therpf.com/f79/my-russrep-obi-wan-anh-lightsaber-188637/

As for durability, I had to weather the finish quite a bit to expose the brass again. We're talking about steel wool, ammo tumbler, and rolling the part around on a concrete slab. The finish isn't indestructible, but it's quite tough. :p

Risu said:
@Filandrius, have you used that stuff before? If so, how quickly does it work, how durable is the finish, and how dark does it make the brass?

As mentioned before, I have brass black and it's not very good. Most effective chemical I've been able to find, but not very good.
Click to expand...
 
I work making various interior design pieces pretty much all made from brass these days, I have to colour up brass on an almost daily basis. We don't often get asked for a completely black finish but I have achieved this several times on pieces. We use a chemical solution which looks very similar to the above bottle just under a different brand name. There are various different solutions available in the range all giving subtle colour diferences. In the trade they are referred to as bronzing solution. You simply clean the piece then submerge it in the solution for roughly 2 - 5 mins and then remove when it reaches the desired shade. The real key to it is to get the item really clean and grease free. For most pieces I use an electrolytic cleaner which works very well and for larger bits I use an acid based degreasing detergent as they don't fit in my cleaning tank. After cleaning it is crucial not to handle it at a all as this will cause uneven coloring. I also find that its a right pain to do polished brass and if it has a slightly satin finish the colour works so much better. I use fine scotchbrite to rough up the surface and go from there. Hope this helps. Any questions please ask. You can see some of my work here http://joebirtles.co.uk/gallery.html

Most of the pics there are a lighter shade of bronze the bat model I made at the bottom right isrobably the darkest there but even on that I've taken the finish back a little to pick out the highlights.
 
That's some fantastic work you've done. Would you mind sharing the name of the stuff you use? That finish is definitely the level of darkness I'm shooting for. Even using degreasers, isopropyl alcohol, xylene, soap and water, the parts just don't get that dark with any of the stuff I've tried so far.
 
The solution we use now for a dark bronze is called "SAICtone DB" but I don't know if that will be of much help as its just a name given by our suppliers who get it made up themselves they are a UK based company called S.A.I.C. I think it stands for Southdown Abrasives and Industrial Chemicals, unfortunately I think they only deal in the u.k. but you may be able to drop them an email and ask them if they can point you to a U.S. supplier.
I have heard of it being referred to as Armatone AB we used to use this but Southdown's do it a lot cheaper and it seems a better formula.
It looks a lot like the pic someone posted. Its a sort of copper sulfate blue liquid. You dilute it with water at a ratio of one part chemical to ten of water, this means a little goes a long way.

Just checked and noticed Armatone is also a UK brand name registered to Armack chemicals (UK again) but you may also be able to try and email them for some advice on what to buy stateside. If only you were UK based I'd gladly gift you some as I've got a 20 litre bottle of the stuff. Without knowing the makeup its hard to know where in the u.s. sells it.
Try searches for bronzing solutions and go from there.
 
Well thanks for all your help! I'll definitely try contacting those companies and see if I can find a way to get the stuff in the US.
 
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