Quote Originally Posted by thisisdonald View Post
I think the solution you are talking about is a mixture 50/50 nitric/hydrochloric and you dissolve black iron nails in it until they stop dissolving. You then filter it clean, paint it on and let it rust.
You will get different recipes which will give different results.

Its sounds to me like youre trying to find 'the best' recipe to fast track to bluing your barrels. In my opinion you should get some acid and fet bluing a few times before you start on your barrels. Theres more to the process than just the right recipe.

Preperation is the absolute key. But ambient temperature and humidity can gave a huge effect as well. I was doing a barrel once and ibhad one rust day where the humidity must have wentbup or something, but that rust deeply etched my barrel. Only comeback was to completely start again - i didnt and i ended up with a satin sheen blue

Partly true. I read that there are pitfalls and all I want to do is cut down the variables, so a tried and tested solution formula takes out one variable. it seems from your very helpful replies that there is not one. Not without Nitric.