to try something different if the results at first do not turn out as you would have them.
For convenience and speed in blueing guns, three tanks are necessary. These three tanks can be made of 24 to 26-gauge black sheet-steel or iron, such as can be obtained from any sheet-metal shop or stove and furnace installation outfit. They are best made by be
ing bent to shape from a single sheet for each tank, with no soldered joints and therefore no chance to develop leaks. There is however, no objection to making these tanks with the end pieces separate if these ends are welded in place, but this is not necessary.
Blueing tanks should be at least 40 inches long, 6 inches wide and 6 inches deep. A sheet of metal 18 inches wide by 52 inches long will make a tank of about this size. Clamp a piece of 2" x 4" timber as long as the sheet on the metal 6 inches from one edge and bend this edge up at a right-angle. Repeat this on the opposite edge and you have an open ended trough 52 inches long and 6 inches wide by 6 inches deep. Clamp a 6 inch piece of 2" x 4" timber across the bot-
torn of this trough 6 inches from one end and bend that end up at a right-angle. Bend the triangular-shaped pieces developed at each side of this end back along the outside of the sides, hammering them down tightly, then put a rivet through each point and through the side of the tank near the top. Bend the other end up in this same manner, and one tank is made. Make the other two by this same method—or a better one if you can think of it.
The purpose of three tanks is; one for boiling of parts in the degreasing solution, a second for hot water to rinse the parts afterwards, and the third to hold the clean water used for heating the parts, so that the blueing solution will take. You can get along with two tanks by letting the parts lie in the rinsing tank while you clean the first tank thoroughly and fill it up with water to heat the parts in while doing the swab-bing-on of the blueing solution.
The method used to heat the tanks will vary according to the cost and suitability of heating elements in various locations. Where electricity is available at a low rate it is the best method of heating, as it makes no fumes and heats up the shop less than most of the other methods used. This electric heat may be applied by hot plates of 750 watts capacity, four of them being used, with the steel tank bottom set directly on the plates, or two 1000 watt hairpin-type heaters may be used in each tank, one inserted from each end through boiler flanges riveted and welded on each end of the tank as close to the bottom as will allow the heaters to be screwed into the tank. For this type of heater the tank should be covered on sides and bottom with half-inch thickness of cane board insulation and a top, covered likewise, should be kept on the tank. Hardware cloth (coarse-mesh heavy wire screen) of mesh is placed in the tank over the hairpin-type heaters to prevent parts getting caught beneath the heat ers. The edges of this screen are turned down at each side to support the screen above the heaters and the heaters themselves will support the screen.
If the four hot plate type heaters are used, it will not be necessary to insulate the tank, but a cover should be used. This can be merely a sheet of the black iron a little larger than the tank, and will speed up the heating of the water no matter what kind of heat is applied to the tanks.
The electrically heated tank, covered with Vi" insulation, showing hairpin type heaters, XA" mesh hardware doth screen and strap across one corner to hold jar of blueing solution in place. Parts go from the rinsing tank to this tank for the actual blueing operation«
Next to electricity in convenience for heat is gas. This will give a very even, high heat, its only objection being that it heats the shop considerably. A three or four-burner gasoline or kerosene stove will give equally good heat but usually requires more attention than gas or electric heat.
The gas heated blueing tank, here shown ready for washing the gun parti free of oil in a lye or caustic soda solution.
While we are speaking about heat is a good time to mention that as altitude increases water boils at a lower temperature, and as its sea-level boiling temperature of 212 degrees is none to high a heat for good results in blueing, when you are working at altitudes of
3000 feet and more the water temperature is hardly sufficient for a good job of blueing. Small parts and thin parts that cool off rapidly when removed from the water should be held in the flame of an alcohol torch, or a gas torch with a neutral flame, to have their temperature raised a little. Don't overdo this superheating or you will have trouble with excessive rusting, which will leave a dark brown coating on the steel. The temperature only needs to be raised a few degrees in the torch flame to do a good job of blueing.
Guns must be entirely taken apart to do a good job of blueing as when a gun is left partly assembled, water remains in crevices and after the blueing solution has
The gasoline or kerosene heated tank, here ready for rinsing the parts as they come from the degreasing tank.
been applied this water will run out over the surface as you turn the gun in your hands and will either wash away the blueing solution or will "watermark" it.
After the gun has been completely taken apart, wash all parts in high-test gasoline, using a stiff brush to get into all corners and if necessary use a small screw-driver to scrape away heavy grease and dirt. You can now see all scratches and cuts, which* must be polished out before the blueing is applied if the gun is to look well afterwards.
Use fine files to remove scratches and cuts, then polish the file marks out with carborundum cloth, starting with coarse and finishing with fine grades, polishing lengthwise of the barrel and action, as cross-polishing shows up badly after the blueing is finished.
Examine carefully for rust all surfaces to be blued and if this rust is anything beyond a very thin surface coating, apply hydrochloric acid to these places. Wear rubber gloves to keep the acid off your hands and apply fresh acid continually for several minutes with wads of cotton. If the acid is not used to kill the deeply rusted spots, no matter how well you polish it there will be times when this rust will show spots on the steel after it has been chemically cleaned with lye or caustic-soda solution.
All parts to be blued should now be buffed to a good polish on muslin buffing wheels, using emery paste in stick or brick form on the buff. These buffing wheels can be obtained from William Dixon Inc., 32-36 E. Kinney St., Newark, New jersey. A diameter of 8" is about right for these buffing wheels when run at a speed of 1750 R.P.M., or a 6" wheel at 3600 R.P.M. These wheels can be bought in sections of 18-ply and upward and about 100-ply will make a wide enough buff. They can be mounted on any ordinary ]/\ -horse motor with a standard arbor attachment, which Dixon can supply or which can be bought from any of the home shop equipment manufacturers such as Walker-Turner of Plainfield, New Jersey; Delta Mfg. Co. of Milwaukee, Wisconsin; Sears-Roebuck or Montgomery Ward & Co.
The emery cake used can be bought of William Dixon Inc. in grades from 180, the coarse, to F, the fine. To apply it to the wheel, turn on the motor, starting the buffing wheel, and hold the emery cake against the revolving wheel until it is well coated. Always polish the barrel, receiver and other parts in a lengthwise direction, never crosswise, except where necessary next to a shoulder, and then remove these cross polish marks with a piece of crocus cloth. It will be necessary to renew the emery paste upon the buffing wheel from time to time as the polishing proceeds. Gloves should be worn during the polishing operation, as the parts will get quite hot and if you take hold of a hot spot barehanded you may drop a barrel and receiver on the floor, if the floor happens to be concrete it will not improve the appearance of the gun.
If you desire a wider range of polishing grit than you can buy in the regular emery stick or cake, you can buy carborundum powders in a wide range of sizes from the Carborundum Co. at Niagara Falls, New York. The buffing wheels can be coated with stick-type belt dressing by holding a stick of it against the wheel and after the wheel is well coated you can stop it and rub the carborundum powder into the surface of the buffing wheel.
The wire buffing wheel, used to buff off the rust coating deposited by the blueing solution, leaving the blue film formed beneath the rust.
Sometimes a gun is quite scaly with rust which has eaten slightly into the surface and in these cases it is best to get a circular wire buffer that can be mounted on the arbor on the motor. The wire of this buffer should be of the crinkly type and be of a diameter of .008" to .010". These may be purchased of William Dixon Inc., Sears Roebuck & Co., or Montgomery Ward & Co. A 6" wire wheel will be large enough and in using it, the parts should be buffed lengthwise and do not bury the parts in the wire buff while using it but let the ends of the wires impinge upon the surface being buffed, for it works faster used this way.
After this wire buffing has removed all the loose rust you can get off with it, use a leather buffing wheel coated with the carborundum grains, glued onto it. William Dixon Inc. can supply the leather wheels, called "Bullneck" polishing wheels, and they can also supply the glue, in flake form, which is used to coat these wheels. If you desire you can make a very good substitute for these bullneck wheels by getting rather thin sole leather from a shoe maker, laying enough sheets together to make a wheel 1" thick, and riveting these sheets together about 1" from the edge. A wheel of 6" diameter is large enough. After the center hole is made, it is mounted upon the motor shaft and, with an improvised tool rest to steady a wood chisel upon, use the chisel to true up the edge of the wheel.
Spread the carborundum powder, of #100 grit or finer, upon a newspaper laid upon a flat surface, spreading the grains out evenly, then coat the edge of the wheel with glue and, putting a short piece of shaft through the center to act as a handle on each side, roll the glued edge of the wheel upon the carborundum grains, rolling it back and forth until it has a good coating. After the glue has dried, mount the wheel on the motor arbor, stand out of line with it as you start the motor and let it run a few minutes to throw off any grains that did not adhere to the glued surface.
After the scaly spots are cut down with this leather wheel, buff the parts to a polish with the muslin buff described above.
After all parts are polished, they are ready for the chemical cleaning bath of lye or caustic-soda. Put sufficient water in one tank to cover the parts by an inch or more and add to it a heaping tablespoon of lye or caustic-soda for each gallon of water. Start your heat and be sure that all the lye or soda is dissolved, before you put in the parts to be blued.
Small parts should have wires, about #15 gauge iron wire, attached to them so that the free end of the wire can be bent in a hook over the edge of the tank, allowing the parts to hang beneath the surface of the water.
Thin parts, such as magazine tubes and shotgun barrels, are too thin to retain the heat long enough when the blueing solution is applied to them, so they should have iron rods inserted inside of them to act as heat holders and this has to be done before these parts
Showing a bar of solid steel passed through the thin magazine tube of a shotgun and held in place with wire wrapped around the bar at each end of the tube. The purpose of this is to keep thin barrels or tubes hot while applying the blueing solution to them.
are placed in the lye cleaning solution. The rods can be longer than the tubes or barrels and just beyond the ends of the tubes or barrels drill a hole through the rods at each end, so that iron wire can be placed through the hole and wound around the rods, to prevent them from slipping out of place. The rods should be of a size to fit the tubes or barrels closely.
Many directions that you read for blueing gun barrels tell you to grease the inside of the barrel and insert tightly in each end a hardwood plug, several inches long, that has previously been boiled in lye or caustic soda solution and thoroughly dried. This plug, or rather these plugs, are to keep the water from entering the bore and are also to act as handles. This may be all right on a light-weight rifle barrel of .30 caliber or more, or for a shotgun barrel, but for a heavy-weight barrel of .22 or .25 caliber such plugs are too light and after being in the boiling water for a while they will become rubbery, bend very easily and often work out of the barrel, then, as the inside of the barrel is greased, the water in the blueing tank becomes greasy so that you are obliged to empty it out, reclean the barrel with the degreasing solution, wash out the tank and start all over again. If you wish to plug the barrel in these smaller calibers, grease it inside and drive in wood plugs, flush with the ends and don't try to leave the plugs long enough to use as handles. These plugs may swell and give you some trouble in removing them but, if this happens, drill a hole through the one in the chamber end, just large enough to admit passing a small rod through it and then push out the muzzle plug. The breech plug may then be removed from the muzzle end by inserting a full-sized rod.
In using any solution that does not contain a high percentage of acid there is no necessity for plugging the barrel, as boiling water never hurt the interior of any barrel and the barrel may be wiped out after the blueing is completed and then polished with a tight patch dipped in any good solvent such as FiendoiJ. Some slight discoloration may remain in the barrel but this is quickly removed by the shooting and cleaning. If you are using a "swab-on" blueing solution that is very highly acid, the water in the tank may be neutralized by the addition of a small quantity of caustic potash (30 to 45 grains per quart) as recommended in Angiers book. This is for the water in which you boil the guns to heat them while applying the blueing solution, not the cleaning bath of lye and water.
After the parts are boiled for fifteen or twenty minutes in the cleaning solution, lift them out, taking hold of the wires only on the small parts and handling the large parts with two iron wire hooks of about #10 wire, for from now on the metal must not touch your skin or it will absorb oil from it and the cleaning bath will then have to be repeated. After lifting the parts from the cleaning bath, immediately place them in a second tank of clean boiling water for about ten minutes, agitating them in the water to hasten the removal of any lye or caustic-soda. If you have a large sink with plenty of running hot water they can be thoroughly rinsed beneath the faucet and the second tank can be dispensed with. Do not let the parts touch the sink or faucet while rinsing them.
A illustrates heavy hooks of iron wire, necessary for handling large parts and gun barrels in the blueing, rinsing and degreasing tanks. £ shows swabbing stick, prepared with a swab of surgical dressing fastened upon it, ready for applying the blueing solution.
The parts are now ready to be placed in the tank of clean, pure, boiling water, to be heated so that the blueing solution can be applied. Fill this tank fairly full, so that you will not have to add more water than absolutely necessary while the blueing progresses and the water boils away, for cold water, or even ordinary hot water added, will cool off the boiling water in the tank and delay you.
This last tank should have a J^"-wide strip of sheet-steel fastened across one corner, inside the tank, so that a glass jar to hold the blueing solution can be pushed down rather tightly in that corner, behind the strap. This strap can be soldered in place, but it will hold better if a small rivet is placed through each end and through the side of the tank.
The small l/i-pint salad-dressing jars are the best thing I have ever found to hold the blueing solution, as they seldom break. This jar should be put in place and a small amount of blueing solution placed in it, when the tank is filled with water and the heat turned on to boil the water. A depth of y2" in the jar will be enough of the blueing solution and if more is needed it can be added later.
Distilled water is the best for this final tank, it is not absolutely necessary but water containing a lot of chemicals may cause trouble. Some city water is very pure, containing only a small percentage of chloride-of-lime put in to kill bacteria, and this water is all right to use. If your city water or well water contains various chemicals, which so-called hard water always does, it is safer not to use it but use rain water instead, if it is free of acid and alkalies. This can be determined by getting some litmus paper from your druggist with directions on how to use it.
After the parts have boiled in this clean water for
The best type of jar to use for blueing solution.
a few minutes, lift them out and, in case of large pieces, stand them on end on a table or bench covered with a couple of thicknesses of clean newspapers and apply the etching solution of nitric-acid and water, 1 to 10, or 1 to 13, or the salammoniac priming solution as directed in Angier's book. In the case of gun parts that are casc-hardencd or are of some special anti-rust steel, use Spencer acid, the formula for which is given in Angier's book.
These etchants, or primers, open up tlie pores of the metal so that the blueing solution will take hold readily. They are applied with a cotton pad dipped in the etcliant, which is used with long even strokes on the parts and the parts are returned to the boiling water as quickly as possible afterwards.
As to the blueing solution, Angier's book gives numbers of them, some of which I have used. His sal-ammoniac blueing solution has always intrigued me but I never have tried it. The solution with which I have had the best success, among the swab-on solutions that I have tried, is the Clyde Baker formula. This is given both in Angier's book and in Baker's book "Modern Gunsmithing." As Baker says, it is a basic solution (this is his #1) and you will make slight changes in it perhaps, to meet varying conditions to get the best results. If a red or burnt-orange color appears after the parts are buffed, the solution is too strong for the steel in question, and a small amount of distilled water should be added to the solution in the jar in the blueing tank. If you add too much water and get it too weak, in which case the blue buffs off, leaving the steel bright, more of the solution from the bottle can be added to that in the jar to strengthen it again.
A piece of dowel-rod which has been boiled in lye-water, well rinsed in clean hot water and then dried, is sawed for a distance of 1", lengthwise. Using l^"-wide surgical gauze, insert one end into the sawed slot and wind twelve or fifteen thicknesses of the gauze around the end of the dowel-rod, leaving a few inches more hanging at the end so that this part can be split lengthwise and wound around the dowel in opposite directions at the rear end of the swab and tied, to hold the swab in place. This swab is placed in the solution in the jar and allowed to heat up with the solution, while the parts to be blued are getting hot in the boiling water.
Clean cotton gloves should be worn, so that parts will not be spotted by being touched with bare hands. These gloves will also protect you from the heat of the parts, in fact it is advisable to wear a close-fitting, double-silk or finely knit glove beneath the cotton glove on the hand with will hold the parts while the other hand applies the blueing solution, for these parts are plenty hot. These cotton gloves should be put through a washing and be dried before being used, to remove any oil that might be in the fabric.
A part is removed from the boiling water by its attached wire, or in the case of large parts, by one or both of the hooks and the excess water that lies in crevices is blown out, for if you wish a smooth looking job of blueing the parts must be dry, and they must dry instantly from their own heat when removed from the water. Take the swab from the blueing solution, pressing out all excess solution from the swab against the mouth of the jar, for if the solution runs from the swab over the surface of the work when the swab is applied, the work will be streaked. Cover the surface to be blued as rapidly as possible, using long, even strokes, going over the smaller surfaces, such as receivers, a couple of times. The parts should be hot enough to dry the solution instantly and if they are not this hot, blow on the solution to dry it, or if the heat of the boiling water is not sufficient, hold the part in a torch flame for an instant to raise the temperature, then reapply the solution. Get the part back in the water as quickly as possible and take out a second part. In the meantime, the swab is returned to the solution in the jar as soon as the first part is well coated, so that it can be getting a new load of hot solution. Get the water off the second part and, using the swab as before, coat this part and repeat until all parts have been given a coating of the solution.
Some directions for blueing tell you to buff the parts or rub them with steel-wool after the first coating of the blueing solution has been applied to them, but I have always found that two or even three coatings of the parts with the solution between buffings seems to give a more even coat of blueing, with less trouble from streaks. The parts are returned to the boiling water each time between coatings with the solution, so that they will be good and hot for the next coating.
If you are going to remove the rust coat formed by the solution by hand, you will use a fine grade of steel-wool, which you have first boiled in lye-water to make oil and grease free. A second pair of cotton gloves should be used in handling the parts while buffing off the rust coat, for the first pair that 3'ou use while applying the solution may be wet or have some solution on them and this may cause a spot on the blued surface, so keep the second pair of gloves dry and dhange gloves before the buffing operation.
Remove a part from the water, blow all water from crevices and allow it to dry. You can take your time for this operation, so don't hurry. Take a wad of the clean steel-wool, rub the rusty-gray coating formed by the blueing solution from the surface of the steel, nibbing gently with strokes lengthwise of the piece. Do not rub the steel bright but rub it until a uniform blue or gray-black surface appears. You will need some wire scratch brushes of fine wire to get right up to shoulders and into sharp angles. These should be made of wire of .004" to .005" diameter and they can be purchased of William Dixon Inc. Sometimes brushes like this can be bought at hardware stores or jewelry supply-houses in any large city. The shape of the brush doesn't matter much, but it should not be too wide. If the steel bristles are too long and tend to matt badly in use, a pair of heavy shears or tin-snips can be used to cut them off shorter.
After the piece has been rubbed down on all blued surfaces, return it to the water and start in on another piece and work on through them all, returning each piece to the boiling water to get hot again so that you can give them the next coating of the blueing solution. Repeat this performance on each piece until they are all the color you wish. If a dull red sheen appears upon them, that does not rub oft* easily, this must all be rubbed off even if you have to rub until the steel is bright again, then add a little distilled water to the blueing solution in the jar as was directed above and re-apply the solution to the steel until you get the proper color.
Sometimes bright spots appear which will not take the solution. These are sometimes very small round spots or they may be streaks where a barrel has been rubbed until the surface is burnished and very dense. This will sometimes show up on shotgun barrels of the repeating type, either pump or autoloading, where the forearm rubs the barrel. ITie cure for these spots is a little rubbing with clean, fine, carborundum cloth, 180 grain or finer, and then some of the etchant solution applied to the spot or streak. The barrel is then returned to the boiling water and, when hot, the blueing solution is again applied and the blueing continued.
If, for removing the rust coating between swabbings, a power buff is used, a buff of six-inch diameter of crinkled wire of .004" to .005" diameter is correct. It
Using a Hue wire buff, mounted on flexible shaft, for bulling a shotgun barrel in the blueing process. By running the buff in a horizontal plane, as shown, it is easier to watch the work at the point being buffed. It also prevents wires, which may be thrown from the buff, striking thr face or eyes which will happen if the wire buff is operated in a vertical plane.
should run at about 1750 R.P.M. These buffing wheels of wire can be purchased from William Dixon Inc. or from almost any large hardware supply house such as H. Channon & Co. of Wacker Drive and Randolph St., Chicago, Illinois. In using these wire buffing wheels, the part, being buffed should not be buried in the wheel but should be so held that the ends of the wires just contact the surface nicely. If a very high polish is desired, a finer wire can be specified for the buffing wheel, wire of .0025" or .003" diameter. These wire buffing wheels should be of steel or iron wire, never of brass, and they should be given a good bath in the lye solution and then rinsed before being used. They should be run for a while after the water is drained out of them before being used, so that they will be dry. They should not be handled with bare hands after being chemically cleaned, and after use they can be wrapped in clean paper until used again, so that they need not be put through the lye solution each time, the once being sufficient if they are kept wrapped as directed.
It is often a good plan to empty out the solution that remains in the jar when you are ready to buff off the rust coating, then rinse the jar in clean hot water, put in new solution and put a new swab of gauze on the dowel-stick, before again applying the solution to the buffed surface. Small parts that will easily go into the jar can often be coated by dipping in the solution instead of having it applied to them with a swab. In this way they do not cool off so much and they therefore take the blueing better. As soon as they are lifted from the jar after being dipped, blow all excess solution from them so that they are dry before returning them to the boiling water.
After the proper color has been attained on all parts, boil them for a few minutes, then lift them from the water and blow off all water to dry them rapidly, and immediately coat them with boiled linseed oil, using a piece of canton flannel or a brush, but do not rub them hard. Hang them up and when the oil begins to gum on them in three or four hours, rub it off with another piece of canton flannel and then apply gun oil to all surfaces. Allow all parts to hang until the following day, when the gun oil may be wiped off and the gun assembler). The interior of receivers and other parts where surfaces were not buffed will show a rustlike coating but this can be removed with a stiff brush, like a tooth-brush, dipped in gun oil. The best time to do this is after the linseed oil is rubbed off and while you are applying the gun oil. Allow the gun oil to remain on these unbuffed surfaces until the following day when wiping off the oil applied to the blued surfaces, at which time this oil on the unbuffed surfaces may also be wiped off.
The jar used to hold the blueing solution gradually accumulates a rust-like coating on the inside, which may be removed by placing in the jar a couple of tea-spoonfuls of ordinary liquid bleach, such as Clorox, which can be purchased at any grocery store, then filling the jar to the top with water and allowing it to stand for a few days, after which a cotton cloth is used to rub the coating off and the jar is then well rinsed.
Nickel-plated arms can be blued. Formulas for removing the nickel will be found in Angier's book on Firearm Blueing, but very often the surface of the steel beneath the nickel plating has been left rough, to give the nickel a good grip on the steel, and the work involved in bringing this surface to a polish is so great that the expense is high, except on a gun of your own where time is of no object.
A few years ago a new type of blueing was introduced by the A. F. Stoeger Co. of 507 Fifth Ave., New York City, called "Stoeger's Black Diamond Lightning Bluer." This is a heavy-salt solution, the salts being supplied dry, ready mixed, by Stocger. For pistols and revolvers the five-pound can is recommended, for rifles and shotguns the twenty-pound can. These salts are placed in the tank dry and it is necessary to wear rubber gloves and goggles when doing this, as the dust that rises from the salts will blister your hands and injure your eyes if they are not protected. These salts in a dry state do not harm clothing or shoes but after water has been added to them, at the rate of % gallon for each five pounds of dry salt to make a solution of working strength, any of the solution that splashes on your clothes or shoes will eat its way through the material, so be careful. Of course after the salts have been made up into a solution, no further danger remains from the dust. After being used, the salts may be left in the tank where they will solidify after cooling. Each time they are used some more water must be added to replace any that has boiled away, but it is added a little at a time to bring the solution up to about the same height in the tank that it occupied when first made up. When, after continued use, the solution looses strength, Stoeger can supply rejuvenation salts, which can be added, a little at a time, to bring the solution back to proper strength. The blueing salts and the rejuvenation salts both sell at $3.75 for five pounds, $12.00 for twenty pounds and $20.00 for forty pounds.
The parts to be blued should be cleaned and polished beforehand, just as they were for the swab-on solution blueing, chemically clean, and should not, thereafter, be touched with the bare hands. Stoeger says that a fair job can be done if the parts are only thoroughly washed in gasoline to remove all grease, oil and dirt but that the results will not be quite as uniform as they will be if the parts are boiled in the regular lye or caustic-soda degreasing solution. Stoeger also states that the old finish need not be all removed if it is in fairly smooth condition.
After the water has been added to the salts (evenly distributed along the tank) the heat is started and, as the temperature of the blueing bath should be as uniform as possible, four burners should be used beneath a rifle or shotgun length tank, one being enough of course for the pistol or revolver size tanks. As the temperature of the blueing bath rises, it should be stirred from time to time with a wooden paddle and a thermometer should be used to check the temperature at different points in the bath. Use a deep-fat frying thermometer such as is sold by Sears Roebuck or Montgomery Ward for about 90^, or by the Taylor Instrument Co. through all local hardware stores for about $1.50. This thermometer is supplied with a metal clip on the back, so that it can be clipped to the side of the tank with the mercury bulb in the solution, in order that the parts to be blued can be placed in the solution when it reaches the proper temperature. This temperature varies between 250 degrees and 275 degrees.
The chemically clean parts have wires attached to them, so that they can be placed in and be removed easily from the solution. As barrels do not have to be plugged, a long wire may be run through them and turned up at the ends above the surface of the solution so that the ends of the wire may be grasped to lift the barrels into and out of the solution. When the bath reaches the proper temperature the heat is turned off to prevent the temperature rising too high and the parts to be blued are placed in the bath and allowed to remain there for ten minutes. I find that the finish is improved if the parts are slightly agitated while in the bath by taking hold of the wires attached to parts and moving the parts gently back and fortll beneath the surface of the bath. If you have many parts to blue at one time, only a few of them should be put in at once, so that you can take care of them better, and for this reason watch the temperature of the bath closely, if it begins to cool off much start the heat again to keep it close to the 275 degree mark, to keep the color even on all parts.
After a part has been in the bath for ten minutes, lift it out and move it rapidly about in a cold bath of clean water, which will loosen the greenish scum on the surface. Follow this by placing the part in boiling water, which is done merely to raise its temperature again so that it will dry rapidly when it is removed.
If, when the part is lifted out of the hot water bath, it has a gray color, the blueing solution is too weak and needs to have rejuvenation salts added to it. If the part has a light reddish coating, it should be all right and as soon as it is dry it is rubbed with a piece of wool cloth dipped in any acid-free oil and the reddish coating should rub off, leaving a deep blue color. If the reddish color will not rub off, or if the part is speckled, it indicates that the solution is too strong. If this happens, add a little water to the blueing solution, wipe all oil off the part and wash it with gasoline and as soon as it is dry, place it back in the solution for two or three minutes and then try it again.
As steels vary somewhat, the light gray color may be caused by too low a heat, so check your temperature carefully if this happens and even try the part again, before oiling it, at a higher temperature. You might also try leaving the part in the solution for a longer period than the ten minutes. Conversely, too high a temperature may be responsible for the reddish color not rubbing off. or for the spotted finish mentioned, so if these occur try lowering the temperature if you are sure the solution is not too strong.
Case-hardened steels will take the blue better if they are nrst dipped into a 15% by weight solution of potassium-cyanide in water. Be sure that all parts are perfectly dry before placing them in the blueing solution, for water on them will cause the blueing solution to explode and fly. If any of the blueing solution spatters on bare skin apply cold water in quantities at once, for the salt will stick to the skin and burn into it if not washed off.
The parts need no further attention after having the rust-like coat rubbed off with the acid-free oil, they arc then finished. Stoeger can supply his Black Diamond Finishing Oil at $1.00 a pint, $1.75 a quart, $6.00 a gallon. I find that sperm-oil answers the purpose very well. This can be purchased at drug stores and they can also supply litmus paper with which to test the oil to make sure that it is acid free.
An article in Field & Stream of February, 1938, gave a formula for an immersion process of blueing for which the directions for handling are about the same as the Stoeger process. This formula is as follows:
3 pounds, 1 ounce sodium hydroxide (caustic-soda flakes) 1 pound trisodium phosphate (trisodium) 3 pounds sodium chloride 5 pounds, 1 ounce sodium nitrate 10 pounds of water.
The dry chemicals are mixed together and placed in the tank and the water is then added. The author states that the solution is brought to a boil and the cleaned parts immersed in it for ten minutes, then placed in boiling water for a few minutes and then rubbed with gun oil when dry. Water should be added each time to keep the solution at the proper level in the tank, also to control the strength of it. The author states that only gasoline washing is required, not boiling in a degreasing solution, to remove heavy oil and grease as all the caustic-soda necessary to kill light oils is in the solution itself.
Baker's #1 Basic Hot Blueing solution has given me the best results in gun blueing. If the etching and Spencer acids are used, I have found this to work very well on case-hardened parts. I have thought at times that the addition of 50% more spirits-of-nitre made an improvement in this solution but at other times I was not so sure. This difference may have been caused by a variation in the strength of the nitre, as it loses strength after a sealed bottle of It has once been opened.
I use straight hydrant water but the water here is quite soft, being 99.99% pure. The local water company chlorinates this water before it is put into the mains. Water is what makes the greatest differences in how blueing solutions work, so wherever possible, distilled water should be used. Rain water will be all right provided you test it with litmus paper to make sure that it is free of acids and alkalies, although if it contains any oil, which will not be shown by the litmus paper, it will be useless.
In stating that Baker's #1 blueing solution gave me the best results in gun blueing, I was referring to "swab-on" solutions. The color given by this is no better, except on case-hardened parts, than the color I got with Stoeger's Lightning Black Diamond Bluer, and this Black Diamond bluer is easier to use than the "swab-on" solution although it is more expensive.
The success of any blueing job depends a great deal on the proper attention to all details, for if you slight them the job will show it every time. No universal formula can be given to cover all steels as they vary greatly, so experiments and changes will have to be made as demanded by the job. In the swab-on solution process chemical cleanliness is paramount and must not be slighted.
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