I recently completed some rust bluing on a couple Mauser based bolt rifles. I’ve posted here and other forums, talked to several people, and have yet to find the root of my problem. The issue is getting a good black color. I consistently get a gray color, in addition to a tough reddish rust post boiling. Each cycle gets worse to the point I can’t card effectively and sometimes end up starting over. Other parts do fine, and sometimes all parts blue up nicely. Barrels seem to be the most trouble, with low carbon softer steels reacting favorably. Recently I blued one complete barreled action with no issues. The second barrel gave me fits. It was etched enough I had to re-file and polish it out a second time. The rust was tough enough my usual #4 double cut file didn’t want to cut through it.

Obviously I’ve tried everything, plus changing all the variables, independently, over time. In desperation I added about a tsp of muriatic acid to the boiling water. The barrel came out of the water blacker than the ace of spades, the rust carded perfectly and the final finish was excellent. I was tempted to add some soda ash at first, but ran across some info in Angiers book that specifically mentioned soda ash and boiling water causing red rust. So, I figured I’d do the opposite……I know the change in water was the difference because the untreated surfaces, i.e. barrel tenon, turned dark as well. Not rusty, just dark vs bright metal. The bright surfaces normally stay bright through most if not all the cycles.

I’m posting this to hopefully find help in understanding what is happening, and of course, help other people down the road. Will also be testing again with a scrap barrel and will update.

What chemicals are you using to rust blue with? How do you polish your metal? What is your process procedure? What is the source of the water you are boiling with?

Have used Mark Lees & Gun Goddess. Water from 2 different dehumidifier’s or store bought distilled water. Draw file and polish by hand anywhere from 240-400

You’re not the only one…in the last two years I have had a hell of a time with rust bluing. It used to not be the case. I don’t know what has changed, and like you I’ve altered certain parts of the process thoughtfully to test where the issue might be. Nothing.

My experience mirrors yours and has costs me LOTS of money.

So, you are express rust bluing using the hot water method. We use that method in the shop with old Belgian Blue sometimes. We also cold rust blue with Rustblue American Formula, a product I make. Mausers blue nicely with that, or German Formula which is the same formula used by the German armories.

www.rustblue.com

quote:

Originally posted by Nick Hughes:
Have used Mark Lees & Gun Goddess. Water from 2 different dehumidifier’s or store bought distilled water. Draw file and polish by hand anywhere from 240-400

To be honest it’s a minefield. I could help you troubleshoot it but would need to know every step of your process from rust cycles, times, temp, humidity etc etc. Chemical can go bad, I’m using 15 yr old Goddess that works perfectly, but some others go bad.
Poor conversion is from bad water, you have to get a good source of distilled water is guaranteed to be 100%. Demineralised is no good. Boiling tank 316 stainless steel. Steaming hasn’t worked for me. The list goes on.
Keep at it.

Use my products and follow my instructions and you will get consistent and predictably good results. It is just basic chemistry, but there are some rules you have to follow. I've got thousands of customers and many newbies getting great results on their first try. I'm available to troubleshoot if you need me.

Bob

I made up a solution of Nitric acid and Hydrochloric Acid with steel wool. I followed a recipe from the web. It is at least 10 years old. I wonder if it will work or should I discard it?

quote:

Originally posted by Aaron Little:
You’re not the only one…in the last two years I have had a hell of a time with rust bluing. It used to not be the case. I don’t know what has changed, and like you I’ve altered certain parts of the process thoughtfully to test where the issue might be. Nothing.

My experience mirrors yours and has costs me LOTS of money.

Try adding the muriatic acid. It definitely worked, I just wish I know what it did on a chemical level and what was keeping the rust from converting before.

quote:

Originally posted by Nakihunter:
I made up a solution of Nitric acid and Hydrochloric Acid with steel wool. I followed a recipe from the web. It is at least 10 years old. I wonder if it will work or should I discard it?

I’m not a chemist but this recipe doesn’t have a good shelf life because the nitric and hydrochloric acids react causing nitrosyl chloride. I’ve heard that the Pilkington solution is made from this recipe and I’ve had a failure using old Pilkingtons.

I gave up on boiling, and steam instead. What I've found is that I need to rust less, and card more thoroughly. More cycles, less rust each time. The first two or 3 cycles on a barrel just barely turn it grayish, and the steam makes it all blotchy throughout. Card that off as well as you can, and it will still be blotchy. But, by cycle 5 or 6, it will start looking good, and by anywhere from 6 to 8, it will be dark black and even. I can get 4 or more cycles per day, since I don't let it rust as much.

For years, I couldn't get dependable results, until I tried again with steam to convert, instead of boiling. Steam has the advantages of taking less space, being easier, and using less fuel. Win every direction.

trying to upload some pictures:

ssdave, which solution did you use?

It looks great.

Dave,
Your giving away all my secrets....I still boil though.
Steve