Question about Birchwood casey aluminum black...

[Servo77]

Will it rust steel like cold blueing can if it gets down into a crack between parts. I know that bluing will do that because a budy touched up his ruger mark III pistol's finish with some cold blue and some got between the bolt and the reciever....next time he got it out, the bolt was rusted shut. Not sure if aluminum black will have the same effect beccause it is an aluminum treatment....but it will color steel.

I wanna touch up some spots on an used ar that I bought but am afraid of the stuff getting down in the foward assist and the retaining pins and causing problems with the steel parts.

 

[Jimro]

if it colors steel then yes it can/will cause rust. Bluing, blacking, and browning are all just various forms of oxidation, and left unchecked the oxidation will always go to the lowest energy level, plain old rust.

Jimro

 

[Servo77]

I did not realize that...any other input? It's an older bushmaster that I got for a song...but it is pretty rough looking.

 

[Scorch]

Aluminum black is not cold blue, it is a polymer with dye in it. It should not cause rust, but it can glue pieces together slightly if you get it into tight spots. If you have any doubt about whether there is enough clearance, disassemble the parts before using it.