The following recipes are recommended for preventing rust on iron and steel surfaces: -

(1) Caoutchouc-oil is said to have proved efficient in preventing rust, and to have been adopted by the German army. It only requires to be spread with a piece of flannel in a very thin layer over the metallic surface, and allowed to dry up. Such a coating will afford security against all atmospheric influences, and will not show any cracks under the microscope after a year's standing. To remove it, the article has simply to be treated with caoutchouc-oil again, and washed after 12 to 24 hours.

(2) A solution of indiarubber in benzine has been used for years as a coating for steel, iron, and lead, and has been found a simple means of keeping them from oxidizing. It can be easily applied with a brush, and is as easily rubbed off. It should be made about the consistency of cream.

(3) All steel articles can be perfectly preserved from rust by putting a lump of freshly-burnt lime in the drawer or case in which they are kept. If the things are to be moved (as a gun in its case, for instance), put the lime in a muslin bag. This is especially valuable for specimens of iron when fractured, for in a moderately dry place the lime will not want renewing for many years, as it is capable of absorbing a large quantity of moisture. Articles in use should be placed in a box nearly filled with thoroughly pulverized slaked lime. Before using them, rub well with a woollen cloth.

(4) The following mixture forms an excellent brown coating for protecting iron and steel from rust: Dissolve 2 parts crystallized iron chloride, 2 antimony chloride, and 1 tannin, in 4 water, and apply with a sponge or rag, and let dry. Then another coat of the paint is applied, and again another, if necessary, until the colour becomes as dark as desired. When dry, it is washed with water, allowed to dry again, and the surface polished with boiled linseed-oil. The antimony chloride must be as nearly neutral as possible.

Iron Parts Rust Preventives 451

(5) To keep tools from rusting, take 1/2 oz. camphor, dissolve in 1 lb. melted lard; take off the scum and mix in as much fine blacklead (graphite) as will give it an iron colour. Clean the tools, and smear with this mixture. After 24 hours, rub clean with a soft linen cloth. The tools will keep clean for months, under ordinary circumstances.

(6) Put about 1 qt. fresh slaked lime, 1/2 lb. washing soda, \ lb. soft soap in a bucket; add sufficient water to cover the articles; put in the tools as soon as possible after use, and wipe them up next morning, or let them remain until wanted.

(7) Soft soap, with about half its weight of pearlash; 1 oz. of the mixture in about 1 gal. boiling water. This is in every-day use in most engineers' shops in the drip-cans used for turning long articles bright in wrought-iron and steel. The work, though constantly moist, does not rust, and bright nuts are immersed in it for days till wanted and retain their polish.

(8) Melt slowly together 6 or 8 oz. lard to 1 oz. rosin, stirring till cool; when it is semi-fluid, it is ready for use. If too thick, it may be further let down by coal-oil or benzine. Rubbed on bright surfaces ever so thinly, it preserves the polish effectually, and may be readily rubbed off.

(9) To protect metals from oxidation - polished iron or steel, for instance - the requisite is to exclude air and moisture from the actual metallic surface; wherefore, polished tools are usually kept in wrappings of oiled cloth and brown paper; and, thus protected, they will preserve a spotless face for an unlimited time. When these metals come to be of necessity exposed, in being converted to use, it is necessary to protect them by means of some permanent dressing; and boiled linseed-oil, which forms a lasting film of covering as it dries on, is one of the best preservatives, if not the best. But in order to give it body, it should be thickened by the addition of some pigment, and the very best - because the most congenial - of pigments is the ground oxide of the same metal - or, in plain words, rusted iron reduced to an impalpable powder, for the dressing of iron or steel - which thus forms the pigment of red oxide paint.

(10) Slake a piece of quick-lime with just water enough to cause it to crumble, in a covered pot, and while hot add tallow to it and work into a paste, and use this to cover over bright work; it can be easily wiped off.

(11) Olmstead's varnish is made by melting 2 oz. rosin in 1 lb. fresh sweet lard, melting the rosin first and then adding the lard and mixing thoroughly. This is applied to the metal, which should be warm if possible, and perfectly cleaned; it is afterwards rubbed off. This has been well proved and tested for many years, and is particularly well suited for planished and Russian iron surfaces, which a slight rust is apt to injure very seriously.