shooter50 wrote: ↑
Tue Jul 07, 2020 12:33 am
Thank you. Sorry about the delay, got buzy with Covid19.
Rust Blueing or Browning is a process which involves creating a thin layer of rust on the metal (Ferric oxide) and converting that rust to Magnetite ( Ferrous Ferric oxide)by boiling in water, for the blue, brownish or blackish blue appearance. Browning and rust bluing are the same process. Browning is the name used for this process in the Military, Para Military, and the Police forces. Contrary to perception and what has been posted elsewhere on this forum they are the same. The final color of the firearm depends on the browning solution and the steel involved and can range from brown to blue to black. The process is time consuming and involves the following steps for that professional finish which one sees on high quality firearms. Unfortunately this procedure is rarely followed by Indian Gunsmiths because of which Indian rust blued firearms have a patchy painted appearance. The final appearance of the firearm depends much more on the procedure followed than the Browning solution, hence I shall describe the procedure first.
1. De greasing (Preliminary)
2. Polishing and preparing the firearm
3. De Greasing (Final)
4. Application of the Browning solution
5. Rusting in a humid atmosphere
7. Carding or Scratching
8.Repeat of process 3 to 6 till the desired finish is obtained often 8-10 times( Even More)
11. Wax polishing
Any firearm is bound to have grease and oil on it hence it has to be de greased . The ideal way to do it would be to boil the firearm in a caustic soda solution and then wash with water and wipe with Acetone. For preliminary de-greasing boiling in Nirma or Surf solution and scrubbing with petrol shall suffice. I do preliminary degreasing simply because i hate to work on an oily firearm and also because its easier to determine the extent of polishing needed on a clean firearm
Polishing and preparing the firearm:
The old blue/paint must be stripped to the metal and the firearm polished. Best to do it by hand using emery paper starting from 180 and moving up to 600 grit. The process has been elaborately described in Para 9 Part B of my initial post above.
Once you have polished and finished the firearm to your satisfaction you need to do a final degrease to make it fit for application of the browning solution. Wear rubber gloves. Boil in Caustic Soda, rinse with water, and scrub with Acetone is the gold standard. Boilng in Nirma solution and then throughly scrubbing with petrol will also suffice if you are short on the above supplies. Touch the firearm only with clean gloves, never with the hands because the metal may colour differently on these areas and mar the finish. Gloves available as protection for COVID19 do really well . Make two wooden dowels, insert one at the muzzle end and the other at the breach. Do not hammer them very tight,Wooden Dowels.jpg
Application of the Browning Solution:
For the first three coats, take a wad of cotton dip it in the solution, squeeze it to remove most of the solution , then gently apply the solution in longitudinal passes starting from the muzzle end. Use gloves and hold the firearm by the wooden dowels at the muzzle end. The process is much like painting, each pass mush overlap the other only by a small margin.Do not vigorously rub down on the metal with the browning solution.
After the application of the Browne the firearm must be allowed to rust. For Indian climate, in the Monsoon season about 4 hrs is enough with the solution. Winter maybe 6 -8 hours. Summer about 6. No need to rust for more than 12 hours. If you let the solution rust for more than 12 hours, you will get thick rust which may give u a black color in only 4 coats but the finish would not be satin smooth. Slow rust always gives a superior finish. Holland and Holland often do 12-15 coats. No need for a rusting chamber in India, It is hot and humid enough, jut lean the firearm using the wooden dowels in a secluded corner free from wind gusts. Pick it up wearing gloves and by holding only the wooden dowels. No touching the metal. After the first application you should have a thin layer of golden brown rust on the firearm.
This as the term implies means to boil the firearm in water for 10-15 minutes. You need a browning Pan. Its not available in the market but any fabricator especially those who make Air coolers can fabricate it for you. The dimensions should be long and wide enough to completely immerse the firearm. I have a browning pan of the size 40" L, 6" H and 5"W.Boiling Pan.jpg
ideally you should use boiled water but my experience says tap water if from a lake or river municipal supply is as good.Do not use well or tube well water. Water from the RO is perfect. The boiling converts the rust (Ferric Oxide)into Magnetite (Ferrous Ferric oxide)which imparts a dark colour to the metal. Add a pinch of Caustic Soda to neutralize the solution and protect the rifling while boiling the firearm. The key here is to use the iron clips to hang the firearm from the wooden dowels so that no part touches the pan while boiling.Simple wire hooks.jpg
Carding or Scratching:
Carding essentially means removing the excess rust from the metal so that only a thin layer remains. Therefore you have to scratch the metal. It has to be done in a way that you don't scratch away the rust completely, only remove the excess. For this purpose what you need is a soft steel carding brush. Unfortunately these are not available in the country. If you don't have a brush u can use 0000 steel wool which is available at Amazon.0000 Steel wool.jpgCarding Brush.jpg When u card the firearm after the first application of brown, rusting and boiling you will notice that the colour after carding lightens appreciably. This is fine, with each coat and repeat of the process it will darken and the shine will keep on increasing. When i did not have a carding steel brush the only other apparatus that worked was a thick flannel cloth and a stiff nylon brush. Vigorously using a shoeshine movement, one can remove the excess rust but the shine is not as good. Needless to say i have not seen this step performed at any of the Police/Army armories nor is it practiced by the private Gunsmiths hence the poor quality of our work.
Repeat of the Process:
You must repeat the process outlined above at least 8 -12 times. The firearm must be only touched with clean gloves if required. The touch points can be wiped clean with Acetone. The application of browning solution after the first 2-3 passes needs to be done differently. One the firearm gets colored applying too much browning solution will lighten that part and give u a streak marring your effort!. Use a sable brush, Sable Brush.jpgfound in any shop which sells paints for artists. Dip it in browning solution, remove the excess liquid and brush lightly in longitudinal passes with a small overlap between each.
This just means adding a level teaspoon full of caustic soda to the boiling solution to neutralize the effects of the browne to prevent after rusting. ( After rusting is very common in shoddy efforts because this step is omitted). Rinse with water afterwards and dry.
The firearm must be now coated with oil and left overnight. No need to soak in oil for a few days as the local Gunsmiths and the Security forces armories do.They do this step because they omit the neutralizing part.
Wipe the firearm dry, it should hopefully have a brilliant dark sheen on it. Take waxpol car polish, apply it on the blued parts, let it dry for 30 mins and then polish it with a cloth. If you have followed the steps outlined above and been careful with polishing,de greasing and application of the browne(browning solution) your finished product should be able to stand in any of the famous gun-rooms. Depending on your stock work of course.
The Browning Solution
Unfortunately we in India do not have access to Gunsmithing supplies from Brownells or Midway USA and therefore have to do with Indian Gunsmiths who are either reluctant to share their product or peddle trash in the name of blueing salts in the the market. An absolute bible on this subject is Firearm Blueing and Browning by R H Angier. 51lKJ48sOnL._AC_SL1500_.jpgUnfortunately it is not for the beginner or the uninitiated. I shall give you preparation details of 2 Browning solutions which have been used successfully by me and can be made from locally available chemicals.
Before we embark on making a Browning solution you must have a few essential items. If you don't have them, then borrow them from a friend who works in a Chemistry Lab in a college or a school. Or else go to the lab with your raw materials and make the solution.
1 A measuring cylinder to accurately measure out the volumes
2. A conical glass flask to mix the ingredientsMeasuring Clyinders and Conical Flask.jpg
3. A weighing balance to measure out the ingredientsBalance.jpg
A. SWISS BROWNING SOLUTION.
I have found this to work excellently on most British and German guns giving a deep blue black with only 5-6 passes.
The ingredients can easily be purchased from a shop selling chemicals and laboratory equipment for schools and colleges. Every city has such stores.
Ferric Chloride Solution 29% 150gm
Copper Sulfate 20 gm
Nitric Acid Concentrated 60 ml
Spirit of Nitre 40 ml
Distilled Water 1 litre
The first step
is to make the 29% Ferric Chloride solution. Ferric Chloride is easily available in the stores mentioned above it is also used for etching printed circuit boards, it comes in powder form packed in plastic bottles. Ferric Chloride is bright yellow but quickly absorbs moisture from the air and turns brown very quickly so keep the container tightly shut. Measure out 120 ml of distilled water using a measuring cylinder and pour the water into the conical flask. Now add 40 gm of Ferric chloride to the water, adding 5 mg at a time and vigorously shaking the conical flask.You have to add small quantities of Ferric Chloride to the water and shake because the reaction is exothermic and a considerable amount of heat is produced. By the time you dissolve all 40 gm of ferric Chloride in water the conical flask shall become hot . Allow it to cool, you now have a reddish brown solution of Ferric Chloride.
The second step
is to add 20 gm of Copper Sulfate to this solution, don't do it in one go add 10 gm at a time, shaking the conical flask to dissolve the salt.
is to measure out 60 ml of concentrated Nitric Acid in the Cylindrical measure and gradually add the acid to the solution above, shaking all the time to mix the ingredients. The solution should turn green.
is adding the Spirit of Nitre. Also called Sweet Spirit of Nitre. Ethyl Nitrate.This is a difficult chemical to get. The one place you can get this is from a shop specializing in supplies to the Police/Para Military forces. Just measure out 40 ml and gradually add to the solution. If you are unable to get Sweet Spirit of Nitre then add 50 ml of Ethyl Alcohol instead. It is practically the same.
would be adding to the solution one litre of distilled water. This is easily obtained from any petrol pump as distilled water for batteries. Your Browning Solution is now ready, put it in a glass stopped bottle. It should have a grassy green colour.
Use the Browning solution and follow the procedure outlined above diligently. With a little bit of practice you can achieve a finish comparable to any in the world. In the next part C I Shall describe the preparation of another Browning Solution used by the Winchester Arms Company. This works great on American Steels and gives a really dark finish.( Which I personally do not like