INSTRUCTIONS FOR DO-IT-YOURSELF SLOW RUST BLUE

This is our humidity box with the top removed. The box is bolted to the wall, at a convenient height for loading and unloading. There are small 1/4 inch holes drilled in the top and the sides of the box, to vent out excess moisture. Note the little white box right end, with the white electrical cord. That is a small vent fan. Note the round pan of water in the bottom of the box is setting on a hot plate. Note the round pan of small parts setting on left end on the cross members. The larger parts are mounted on the length wise wooden dowels. This is a Winchester 86 take-down with the forth coat of rust being put on.

            Dimensions of the box are not critical. This one is 48 inches long, the width of a sheet of plywood. It is 14 inches wide and 18 inches deep. You can blue without a humidity box, but  a humidity box is a handy and convenient tool to have around a blue shop. This one was made from cheap 1/8 inch plywood, and is 7 yrs old. The round pie, cake, pans are rust free aluminum, $1.69 at our local hardware. The vent fan, a K-Mart special $19.95, the hot-plate a Wal-Mart special $12.95.

            We use the humidity box as a convenient place to put the parts to be blued, in the summer time, with no heat applied to the pan of water, and let the hot humid summer do the rust for us. But the 9 months or so a year where we need to try and control the heat and humidity, the box is mighty handy. 

            We are now assuming the gun parts to be blued are polished out, and spotlessly clean, ready for blue.

            We use a dish washing detergent and warm soapy water to clean the parts. I use cotton balls (real cotton) to apply the bluing solution, but some prefer natural sea sponges. Use either one you like, and get used to how they work, and either is satisfactory.

            For the first coat of blue, ONLY THE FIRST COAT, I have my cotton ball damp, but not soaking wet. And I rub back and forth like I am washing the gun parts to be blued. And I get a new damp cotton ball and go over it again, at least once. For this first coat, going over it three times is OK. What you are doing is applying a very smooth even coat of rusting chemical. And if done right, that first coat will look like you platted the gun parts with copper, when they are ready to cook off.  To achieve this you want your cotton ball damp enough to apply a coat of rusting chemical, but not so damp that you are leaving puddles behind your swab, on the part you are bluing.

             We use vinyl or latex throw away gloves to apply the bluing solution, because it is not advisable to put nitric acid on your skin, and greasy fingerprints can ruin a blue job. Once your parts are coated with your damp swab, place them in the humidity box, to rust.

            Here in Wisconsin, in the summer time, hot days and high humidity, like 80 degree temperature, and 80% humidity, are ideal natural rusting conditions. Under these rusting conditions your parts will be ready to cook off in about three hrs. In the winter time our hot-plate under the pan of water, if set on low, will make pee warm water. This again will be ready to cook off in around three hrs. In the deep winter months we turn the humidistat in the shop down to 50 degrees, and let the blue set overnight (8hrs) before cooking off next morning. These low temps allow this ONLY in the winter. Try this in the simmer, and you can rust deep pits in the metal. And if you wish to move faster, turn the heat up to between low and medium on our burner, DO NOT GO SO HIGH THAT THE WATER  BOILS,  and we can cook off every hr. Either way you do it, the slow way, or fast way the blue is good. JUST WATCH IT AND DO NOT ALLOW TO OVER-RUST, You will get used to your particular conditions and know how long to leave it rust with experimentation. JUST REMEMBER CONDITIONS ARE ALWAYS CHANGING. What you did today, may be too much., and or not enough tomorrow. You will have to pay attention when you are slow rust bluing, keep inspecting it every hr or so to make sure its not over rusting. When its looks rusty, its ready to cook off, regardless of how long it took to rust.

            Cook off the rusted parts, and allow them to boil for at least five minutes. You will need clean water. We use deionized water, have a deionizing unit in the shop. But that can be expensive for home use. But tap water is seldom good. We suggest using distilled bottled water, but the distilling process must be reverse osmosis. It should say reverse osmosis right on the bottle. Our cooking tank is shaped like our humidity box, but smaller, 6”X 6” X 40”. We use mechanics wire strung across, and lay barrels length wise across the wires. We put small parts in a wire basket, from Brownell’s. This is to keep parts off the bottom of the tank. You want the parts suspended, not laying on the bottom of the tank. When I have just small parts to be blued, I cook them off in a pot on the kitchen stove, easier than heating up the big cook off tank.

            This cooking off converts the rust to black oxide, hence the blue black color. And cooking off stops the action of the rust. And with our slow rust blue there is no after rusting.

            We use heavy rubber gloves to lift the parts out of the hot water. Set the parts on racks to cool.

After cooling to touch, about fifteen minutes, we card off. You can card off by hand, using steel wool, BUT WASH THE STEEL WOOL IN ACETONE TO REMOVE THE PROTECTIVE OIL IN IT. We use a soft carding wheel, from Brownell’s, turning only 500 RPM. You want to card off the black velvet, not the coat of blue you just put on. The velvet will come off easy.

            Next we repeat this until we get the desired build up of blue, usually five or six coats will be plenty. FOR THE FOLLOWING COATS, WE USE A DAMPER SWAB THAN WAS USED FOR THE FIRST COST. For the following coats, you can rub off as much blue as you are putting on. The damper swab allows you to go over it only once, lightly, leaving a good coat of blue, without rubbing much of the previous coat off.

             If your local conditions will allow it, you can rust all year long without a humidity box. Some local conditions allow you to let the rust set overnight, for 8 or 9 hrs. I can’t do that here where I live without over-rusting, in the hot humid summer time. Can cut the heat in the shop and do it in the winter-time.

            We suggest bluing one small part at first, a screw for example. Learn to blue that screw well, and you will know how to blue your gun well.

 WINCHESTER RESTORATIONS

http://www.winrest.com/