Brass Ageing Question-Ammonia Fuming

[Muleskinner]

As we speak I have had brass parts from my rifle in a sealed container with ammonia "fuming" for about 24 hrs...I can tell the highly polished parts have dulled a small amount but not really enough,my question is how long can I leave them in the fumes?....how long does it normally take?

[rich pierce]

Should be done.  I've heard it can weaken the brass.

[axelp]

I have used plain old yellow mustard and it will tarnish brass.

K

[Don Getz]

I usually only leave them in an enclosed container overnight, might be 10-12 hours.   They usually come out rather well
tarnished.   Althought, at times, certain types of brass didn't really react that much.....if they didn't, I just put them on the
gun the way they turned out, then left nature take it's course..........Don

[Muleskinner]

Thanks guys.I think I will take Don's advise and just let it age on it's own

[cmac]

Dirty cleaning patches have worked well for me

[Collector]

Back to the beginning, for just a minute.  There is Household Ammonia at about 6 to 7% concentration and there is Commercial Ammonia at about 12%.  Huge difference in exposure time versus results.  And yes, it does make the brass brittle (at least the bronze/alloyed stuff they use for belt buckles.)  Don't ask me how I know... 

Having an airtight seal is important.  I used a flooded glazed ceramic pan/container and a clear plastic top that fits inside the interior dimensions, allowing the liquid ammonia to completely seal the edges to prevent any air exchange or infiltration.  You might have to put a small weight on top of the plastic cover.

You've been given great advice by the forum members.  Good luck!!

[LehighBrad]

I've heard or maybe even read somewhere of actually spraying flat black rustoleum spray paint primer on the brass and then lightly buffing off most of the primer leaving darkened areas in the creases, nooks, and crannies of say, the trigger guard and such. Never tried it....don't know how it would turn out. But would love to see an example of it.

[Birdhunter]

Birchwood Casey makes Brass black that works well & instantly.
Curt

[B.Habermehl]

Another chemical to try is Liver of Sulphor. It should be available at any of the bigger craft stores. It's bottled specifically for ageing (antiqueing) brass and copper. Works quite nicely, I schmeared it on my brass parts with a cleaning patch and left it sit overnight. I see no reason you couldnt reapply but I saw no need for this batch of parts. They tarnished nicely and rubbed back with steel wool just about as nice as I could have asked.

[Nate McKenzie]

I use 44-40 gun blue and rub it back with 0000 steel wool after it dries.

[Ron Brimer]

Birchwood Casey SUPER BLUE works instantly on castings and sheet brass. To Grey down steel use Mayo directly from the jar. swirl it around on the part looks like faded case hardening. Polish the brass with 0000 steel wool, until you get the tarnish, or polish you like. Been doing it for years.
          Ron B

[Dr. Tim-Boone]

I haven't tried the condiments yet... but what Don said has been my experience with 12% ammonia.. just over nite. As Nate mentioned the 44/40 from Brownell's works pretty well too..