US1565536A - Process of removing rust - Google Patents

Description

of Louisiana,

' iron and steel plates and articles Patented I Dec. 15, 1925.

1 UNITED STA WAL'IER EMIL WANDEL, OF NEW ORLEANS, LOUISIANA.

PROCESS OF REMOVING RUST.

No Drawing.

To all whom it may concern:

Be it known that I, 'WALTER EMIL WAN- DEL, a citizen of the United States, residing at New Orleans, in Orleans Parish, and State have invented certain new and useful Improvements in Processes of Removing Rust, of which the following is a specification.

This invention relates to processes of removing rust; and it comprises a method of removing rust and preventing rust wherein rusted metal articles are covered with a layer of a composition containing one or more drying oils, basic bodies, and, usually water; the composition frequently comprising linseed oil associated with water and soap as an emulsion; the layer allowed to remain for a sufficient time to dry or set up to a certain extent, and the layer then removed, together with the rust, by flaking or peeling it off; all as more fully hereinafter set forth and as claimed.

It is a desideratum in many relations to be able to remove rust and corrosion from with a minimum of labor and expense. Ordinarily, rust is removed by chipping or grinding in some Way; an operation which is laborious, expensive and often not very satisfactory. In the present invention, I have devised a better way of effecting removal of rust and atthe same time of preventing its recurrence. In this invention, I treat the rusted or corroded metal surface with a composition containing a drying oil and certain bases (usually alkali) in such a manner as to form a substantial film and then allow this film or layer to set or harden to a certain extent;

sufficiently to form a coherent skin. This skin with the included rust is then simply flaked or scraped off.

I have found that linseed oil and other dryin oils, such as soy bean oil, blown fish oils, hina wood oil, etc., when applied to a rusted or corroded surface enter the rust or permeate it with some readiness, and will, of course, dry in time; more quickly, however, if heated to give a coherent film. But the penetration of linseed oil and the other drying' oils into rust when used by themselves is not as good as is desired for my purpose, nor do they, so to speak, force themselves be tween the metal and the rust at the points where the rust adheres to the metal. I But by various additions to linseed oil and the like, these oils may be given this property.

'tion may be-made by Application filed December 11, 1922. Serial No. 606,289.

I find that the presence of a certain amount of a body having, chemically considered, n'lore or less basic properties is desirable; th s body giving. in combination with fatty acids, a certain amount'of soap or soap-like :ompos1tio-n. The soap may be formed at the expense of part of the linseed oil, etc.; or may be separately added. One such addition which may be made to linseed oil is ordinary soap; either soda soap or potash soap. The soap may be made of linseed oil, fatty acids, or it may be of any of ordinary kinds of commercial soaps; green soap, hard soap, etc. If the soap is used in connect1on with water, a better composition for my purposes is secured. In one typical embodiment of my invention as regards such soapy matters, ordinary soap is dissolved in water to give a thick but fluid mixture and th1s mixture combined with linseed oil in such a manner as to emulsify the two. A proportion of 1 part by volume of strong soap solution to 4 parts by volume of raw linseed oil works well. I have found that these compositions act somewhat more efiicaciously if allowed to stand and age for a period of time, say, several months. Any rancidity that may develop in standing is not injurious and may be advantageous to the properties of the compositions for the present purposes. It is best, where the materials are allowed to stand in this way, that they be in contact with finely divided iron; 1ron turnings, iron shavings, scrap iron, etc.

Instead of using commercial soap, a certain amount of what is termed linseed foots may be worked into linseed. oil. With linseed foots, a good proportion is about per cent linseed foots and 40 per cent raw linseed oil. This composition also works better if allowed to stand for a time in contact with iron in such a condition as to give an extensive surface. A less advantageous composidirectly adding ordinary hard soap (which usually contains considerable water) to warm oil and agitating or stirring. The mixture is apt to separate, however, more than that made in the manner first described. Still another composition which is efficacious for my purposes 1s made on a somewhat different principle, using other metal bases in lieu of the alkali bases of'ordinary soap. I have found that an eflicient composition for the present purposes ma ings or lings with linseed oil for a time be made by grinding iron turn-' to obtain distributed iron oxid through the oil. It is better to grind the oil and iron together hot. It is desirable to allow this mixture also to stand for a time be-- fore using. The iron oxidizes more or less, giving iron oxid in reactive form to the oily composition. Instead of using iron, another metal orits oxid may be used. I find that copper oxid, for example, is desirable; and

in lieu of using iron, I may use some'form'of oxidized copper; verdigris, copper oxid, copper carbonate. etc.

With raw linseed oil there is a certain proportion of free fatty acids present, and in any linseed oil these fatty acids are apt to develop on standing. The various metallic oxids, such as iron oxid, copper oxid, ets., combine with these fatty acids, giving heavy metal soaps. Heavy metal soaps made in other ways, such as iron oleate, stearate, palmitate, etc.,, similar copper salts, zinc salts, etc., which are commercially available materials, may be directly added.

Many of the results which I desire to secure-can be obtained by simply storing linseed oil or the like in contact with an ample amount of fine metal, say, iron turnings. Half a ton of iron turnings in a 300-gallon tank of oil gives a good preparation. Many of these compositions using heavy metals are improved by the incorporation of various fatty oils of which I have found codliver oil to be the best, so far as my present experience goes. A composition containing 30 per cent codliver oil and per cent raw linseed oil as the oily component works exceptionally well. Such a composition works particularly readily when associated with heavy metal soaps, and. in the event that the oily vehicle is to be modified by storage in contact with metals. A good preparation is made b storing about 300 gallons of a mixture of 30 per cent of crude codliver oil and 70 per cent of raw linseed oil with a ton of fine iron turnings in a tank open to the air. As oil is drawn from the tank for use, a new portion of the oily mixture may be added for re lenishment. To the oil'thus made, some ver igris, copper carbonate, etc.,

may be added; enough to give the oily mixture a decided green tint.

In ordinary soap, the alkaline base is soda; and such soaps may be used for my purposes. Potash soaps can be used equally well, as can the various alkaline bodies, which in contact with oil will form soaps, such as ammonia, potassium carbonate, sodium carbonate, bor'ax, silicate of soda (water-glass), etc. The presence of the added bodies in all cases seems to improve the linseed oil (and otherdrying oils) as regards the property of infiltration into the rust and of detaching the rust from its adherence with metal.

In the practice of my invention, I ordinarily treat the rusted or corroded surface with a sufficient amount of the modified oil to form a thin film'or layer. This layer I allow to dry for a certain period of time. In cold weather, ;s ometimes I allow drying to take place for from 7 to 24 hours; giving enough time for the composition to penetrate the rust and to set up to form a fairly coherent film or layer. With hot metal, such as steam ipes, the time required for penetration an setting is of course less. The preparation is heat resistant and a rather high temperature in the metal to be treated cannot only be tolerated but is ad-. vantageous. Setting up of the oil may be hastened in the usual way, by the employment of driers, such as manganese linoleate, copper linoleate, etc. Such driers may be added to any of the compositions hereinbefore indicated.

The modified oils used in the present invention are, as stated, resistant to high tem-- peratures, even up as high as, say, 300 C. but their behavior with clean and with corroded metals is quite different. The modified oil, if placed on a clean steam pipe and allowed to set up, forms a coherent close textured film of a paint-like nature; but in the presence of rust, dirt or corrosion, the film formed on setting up scales 011', carrying with it the rust or dirt.

In removing rust by the present method, the metal is left with a clean black surface readily taking paint and the presence of the oily composition hinders re-corrosion for long periods of time.

After the composition has been applied to the corroded surface and allowed to set up to the extent desired, it is simply peeled off, carrying the rust, dirt and corroded matter withit. The metal is then ready for re-painting. The composition may be. applied to the cleaned surface and will now adhere, serving as a protective coating.

So far as my present experience has gone, while I find the other described compositions efficacious and advantageous, I have obtained the best results from a mixture of 30. parts codliver oil, which is the commercial unrefined or crude oil and 70 parts of raw linseed oil, the mixture being digested on iron turnings or the like, for a fortnight or more, with access of air. As oily material is drawn off the iron, new oil may be supplied. The mixture of oils may be directly treated with a little verdigris or copper carbonate.

After treatment by the present process, the surface of the iron is left in a permanent non-corroding condition and it is not necessary to red-lead it or otherwise treat it prior to repainting.

Where I have spoken of linseed oil, or raw linseed oil, I wish it to be understood that I can use boiled oil or refined oil. But

' so far as my present experience goes, the

raw oil is better. Instead of linseed oil, I may use any of the drying oils recited ante, as a substitute for or in connection with the linseed oil. I may note however that I have found raw linseed oil better than any of these other drying oils.-

What I claim is 1. Theprocess of cleaning rusty or corroded iron preparatory to painting which comprises covering the metal with a layer comprising a drying oil and a chemically basic body, allowing the layer to harden sufliciently to form a coherent mass by the drying of such oil and then stripping ofic the mass together with the included rust, etc.

2. A process such as that of claim 1 wherein the drying oil comprises crude linseed oil.

3. A process such as that of claim 1 wherein the oily material used contains raw linseed oil and codliver oil.

4:. A process such as that of claim 1 wherein the basic body present is oxid of iron.

In testimony whereof, I have hereunto affixed my signature.

WALTER EMII) YWANDEL,