by No1Mk3 » 10 Jun 2020, 2:59 am
G'day Oldbloke,
Cold blue works OK if you put the time and effort into it. I have done a few rifles and shotguns and they came up very nice and have endured for many years. the secret is preparation, care of application and not following the method in the instructions! 1st prep the barrel to a fine finish, heat the barrel to around 80C and apply a browning solution, I use Birchwood Casey, then card and rinse, repeat, then apply your Blue solution again I use Birchwood Casey. Card and clean between coats and apply np less than 6 coats. Hot blue is superior most of the time but only just, and doesn't take much more effort or time than a proper cold blue, just the time and effort to make the tanks for hot water, hot chemical then just apply time and effort like the cold blue. You need Potassium Nitrate and Sodium Hydroxide. Traditional rust bluing is the most time consuming but also gives a superb finish, build a humidifier or steamer (humidifier works best, it's a time thing) and rust, card repeat until you get the finish you want. Again the secret to succes is perfect preparation of the parts surface regarding finish and cleanliness. Best of luck, it can be very satisfying, Cheers.