Browning and Blueing of guns and barrels

By Kenneth Giggal

This is an article I was given by a member of my woodturning club. He was unsure where he got it from originally but thinks it was published in Guns review many years ago. I have reproduced it here a closely as I can.

Please Note

All these formulae involve chemicals hazardous to health and the processes themselves have attached risks as well. The Company of Ordinance and its members will accept no liability for injury to people or damage to equipment, guns etc from use of the information published here. By using this information you accept all liabilities.

        Published 23rd August 2001

The Blueing and browning of guns is not a difficult process and by a careful job good results can be obtained by a painstaking amateur. Blueing or browning takes place by chemical action but, no matter how much solution is applied, the finished job depends entirely on the amount of polishing done first. A great deal of time must be spent in getting the parts completely free of grease, old colour and all scratches and scorings. It is a good idea to practise first on an old piece of gun barrel, especially if the draw filling method is to be used. Draw-filing is done with a wide file, well chalked on both sides to prevent deep cuts. Better perhaps, is emery cloth wrapped around a flat piece of wood. Whichever way is chosen, avoid lifting the polisher from the steel surface. Cover the full length of the barrel with long even strokes. This work can not be hurried. It will take a long time to remove all surface scratches and high spots. After polishing with draw-file or emery, rub well with steel wool. Then wash down with alcohol, wiping off afterwards with a cloth saturated in lime water. This will remove all grease and finger marks. Blueing or browning will only take effect on a surface completely free of grease. When treating barrels it is essential to plug the muzzles and chambers with wooden plugs. these serve the double purpose of providing handles and preventing the solution from entering the bore.

Blueing

A cold method.

After preparing metal parts as outlined above, polish down well with a clean dry, soft cloth. Rub over with a cotton wool pad soaked in a nitric acid solution made up of one part commercial nitric acid to two parts water. When the desired colour appears wash off the parts with clean water and polish dry  with a soft clean cloth. Finally rub well with linseed oil. This will produce a very pretty blue colour which should wear quite well.

Two hot methods.

Some complicated hot methods require several galvanised tanks but these two require only one. Size of tank is governed by size of parts to be blued. The ingredients can be supplied cheaply by most chemists who will make them up as required.

Formula "A"

3oz         Sodium chloride

17oz       Trisodium phosphate

5lb 1oz   Sodium nitrate

3lb 1oz   Caustic soda flakes

Place all the chemicals in the galvanised iron tank, together with 10lb of water, preferably rain water. It may be necessary to add a little more water during use to keep the solution at its correct strength. Do this from time to time. place tank on gas heater, kitchen stove ideal and bring the brew to  boil. Place metal parts to be treated into boiling mixture and leave for fifteen minutes. Remove from tank. Wash thoroughly in hot water, and allow them to dry. When dry give a coating of boiled linseed oil and polish gently with a very soft cloth. The result should be a lovely deep blue black colour.

This mixture can be used over  and over again, but if it is thought that the solution is beginning to lose its strength, this can be remedied by the addition of a little sodium nitrate.

 Formula "B"

1oz         Mercuric chloride

1oz         Potassium chlorate

1oz         Potassium nitrate

1½oz      Spirit of nitre

1 pint     Distilled water

This American method is known as the Harvey Lovell formula, after the gunsmith of that name. It has the merit of simplicity and leaves the gun with  a beautiful dark blue colour.

Fill the galvanised tank with sufficient rain water to cover the parts to be treated and heat to boiling point. A small can containing some of the acid solution is suspended by a wire in one corner of the tank so that the solution becomes hot as the rain water is brought to boil. Lower the parts to be treated into the boiling rain water and leave for five to seven minutes. Then take them out of the tank and, using a cotton swab on the end of a piece of stick, apply the hot solution from the can, going over the item completely several times. The hot metal will dry within a few seconds of the swabbing procedure and rust will start to appear. Scrub vigorously with fine steel wool and return the part to the tank for a further five to seven minutes. Remove it, swab several times with the solution again, and steel wool the resultant rust. Six or seven such treatments will bring on a rich dark blue. After the final application, rub of all last traces of rust and wipe down with boiled linseed oil until the metal cools. Then place the treated part aside for twenty four hours. Next day rub down lightly with a soft cloth and just enough petrol to remove traces of excess linseed oil. It is important here to remember that different steels vary greatly in their reactions to treatment by these solutions. Some take colour much more slowly than others and could require several extra applications before the desired colour is achieved.

Blueing of small parts.

For small parts, such as screws, swivels, butt plates, etc. An easy method is to make up a solution of 10% Nitric acid in hot water. Dip the parts in the solution for three of four minutes, then put them in fresh boiling water for an equivalent period. This  remove all traces of acid. Repeat the process if thought necessary, afterwards placing the parts on a wire gauze over a Bunsen burner or a gas ring until they are very hot. Then quench in oil.

Another common method but rather more tedious is the following:-

Formula

91grains     Alcohol (90%)

46 grains    Copper sulphate

35 grains    Nitric acid

91 grains    Spirit of nitre

47 grains    Ferric chloride

46 grains    Sulphuric acid

Distilled water to make up to 5 fl oz

After the polishing procedure, apply the solution and allow the metal to rust. Rusting should take place in about three hours. Wash the parts after rusting in boiling water and clean afterwards with a wire brush. Repeat the process three or four times or until the desired colour appears. Then give a final, careful clean, and rub down well with oil. A very good deep blue should result.

Browning

In browning the fibres of the metal are brought out to show their full beauty, particularly so upon Damascus barrels. The process is similar to that of blueing in so far as the long preparatory cleaning and polishing is concerned. However, browning is best done in a warm, dry atmosphere, as the browning mixture will vary in its length of action according to atmospheric conditions. The following six solutions may be applied either with cotton wool swabs or as directed until the whole surface is treated. The work is then placed aside until until it is covered with rust. (This may take all of twenty four hours, perhaps more). It is then rubbed down with a very fine wire brush and the process repeated until the desired colour appears. When the final colour comes up, wash down in hot water to which has been added a little permanganate of potash. Rinse then in clean water, dry thoroughly, and rub down with linseed oil. A lovely polish can be obtained then by warming the parts and rubbing down with white wax on a soft flannel cloth. A good wax for this purpose can be made from beeswax and turpentine. Waxing imparts a wonderfully fine finish, particularly to barrels. Some of the following formulae have ingredients known by both ancient and modern names, but modern terms are used for convenience.

For browning small parts

4 parts    Water

2 parts    Ferric chloride

2 parts    Antimony trichloride

1 part     Gallic acid

Dissolve the ingredients in the water and leave to stand for a day. Apply cold as directed for other solutions.

To remove old browning

Immerse the parts (not forgetting to plug if barrels are being treated) in hot lime water for about 45 minutes. Remove and wipe down, then place in vinegar for same period. Remove and wipe down with soft rag, and old browning should go.

Please Note

All these formulae involve chemicals hazardous to health and the processes themselves have attached risks as well. The Company of Ordinance and its members will accept no liability for injury to people or damage to equipment, guns etc from use of the information published here. By using this information you accept all liabilities.

        Published 23rd August 2001