|
The secret is cleaning.
I use Acetone or lacquer thinner, or even a soap cleaner like Greased Lightning or kitchen cleaner.
I then give the part a good flush with 90% alcohol and warm with a hair dryer.
Over heating doesn't help, it hurts so don't use a torch.
Depending on the size I may apply the cold blue with a Q-tip or dip in the bottle.
I don't like dipping because this contaminates the bottle of cold blue and after a time ruins it.
I find that gently rubbing with the soaking Q-tip helps.
After it's blackened, rinse with hot water and wipe with a soft cloth.
Cold blue works surprisingly well on brass and copper.
|