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Automobile welding with the oxy acetylene flame
AUTOMOBILE WELDING WITH THE OXY ACETYLENE FLAME
A PRACTICAL TREATISE
Covering the repairing of Automobiles by Welding, with a non-technical explanation of the principles to be guided by in the successful welding of the various metals. Helpful to all users or prospective users of the Oxy-Acetylene flame, since the fundamentals for successful repair welding are clearly outlined.
BY M. KEITH DUNHAM
NEW YORK, THE NORMAN W. HENLEY PUBLISHING CO., 1917
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Automobile welding with the oxy acetylene flame
PREFACE
The use of the oxy-acetylene flame for automobile repairing is by no means new. When the process was introduced into this country ten years ago, the automobile industry, or rather, perhaps, the automobile owner, was the first to recognize its value. Broken frames, requiring ugly patches or the complete dismantling of the car, were quickly repaired with the oxy-acetylene flame. Smashed cylinders, crank and gear cases were made as good as new at a cost but a fraction of a new part.
The purpose of automobile welding then is not to introduce a process rather, to show how to weld properly those parts which should be welded and as well to point out those parts which should not be welded.
The workman who can successfully weld all automobile parts is capable of welding anything, since in the construction of the automobile practically every commercial metal is used. The principles of automobile welding then are applicable to all kinds of welding and even though we are not particularly interested in the welding of automobile parts, we can with profit study the various details of successful automobile welding, since it is principles, rather than details, which must be grasped in any kind of welding, and these principles the author has tried to explain in a simple, practical way.
The purpose of automobile welding then is not to introduce a process rather, to show how to weld properly those parts which should be welded and as well to point out those parts which should not be welded.
The workman who can successfully weld all automobile parts is capable of welding anything, since in the construction of the automobile practically every commercial metal is used. The principles of automobile welding then are applicable to all kinds of welding and even though we are not particularly interested in the welding of automobile parts, we can with profit study the various details of successful automobile welding, since it is principles, rather than details, which must be grasped in any kind of welding, and these principles the author has tried to explain in a simple, practical way.
CONTENTS
- APPARATUS KNOWLEDGE
- SHOP EQUIPMENT AND INITIAL PROCEDURE
- CAST IRON
- ALUMINUM
- STEEL
- MALLEABLE IRON, COPPER, BRASS, BRONZE
- CARBON BURNING AND OTHER USES OF OXYGEN AND ACETYLENE
- HOW TO FIGURE COST OF WELDING
CHAPTER I - APPARATUS KNOWLEDGE
Oxygen Supply Care of Oxygen Cylinder Acetylene Generation Care of Generator Regulators Care of Regulator Creeping Regulators Gauges Care of Gauges Welding Torch Care of Welding Torch Effects of Heat Hose and Goggles.
A workman in any line must have a knowledge of the tools he uses. The operator of the oxy-acetylene flame must understand the principles of his apparatus to avoid serious errors. Knowledge of the gases used, as well as an understanding of the regulators, torch, supplies and shop equipment, is essential to an intelligent application of the flame.
Oxygen Supply - Tank oxygen is today in universal use by oxy-acetylene shops. There is no method of producing it on any small scale which will compete in cost with it. When we specify tank oxygen, we mean that purchased in seamless drawn cylinders under a pressure of 1,800 pounds to the square inch.
The oxygen purchased in this form is produced by two different methods one by the electrical decomposition of water, which consists of two parts of hydrogen and one of oxygen. By this method, which is termed the electrolytic process, the water is decomposed into its constituents and the oxygen after being led into a gasometer is from there pumped into a steel cylinder under pressure. The other process is known as the liquefaction system. The air, which consists of four parts nitrogen and one part oxygen, is frozen. When the air reaches this liquid condition, the nitrogen boils off first, leaving the oxygen, exactly the same as if gasoline and oil were mixed together and placed in an open vessel, the gasoline would first evapor- ate. The oxygen is then led to the gasometer and from there pumped into a steel cylinder ready for shipment.
Both methods produce a commercially pure oxygen with practically no difference between them for welding purposes.
Care of Oxygen Cylinder - Oxygen is a non-combustible element. It will not burn, but it is the supporter of combustion without it nothing will burn. Obviously, some care must be used, since its escape from the cylinder in the vicinity of sparks, a flame or any greasy or oily substances, may be hazardous.
Oxygen is usually supplied in a cylinder with a narrow base which is easily tipped over unless some precautions are used to guard against this. If a truck is employed, the tank is chained or strapped to the truck. If the cylinder is used without a truck it should never be left standing without support, but should be clamped to the wall or the bench, and where this is not possible it should be placed in a horizontal position on the floor. Regulators are sometimes destroyed by the oxygen cylinder being tipped over and care should be taken to prevent this.
Since oxygen is the supporter of combustion, particular caution must be exercised not to oil or grease any part of the oxygen supply line, particularly the outlet of the oxygen tank valve or the oxygen regulator. If any grease is present with oxygen under a high pressure there is an ideal condition for spontaneous combustion and a violent explosion may result.
Due sometimes to natural conditions, but at others to carelessness, considerable water may be present in the cylinder. This water will damage the regulator and as well adversely affect the welding flame. At intervals it is advisable to test cylinders by tipping them upside down and opening the valve slightly to detect the presence of any considerable volume of water. This method will expel the water from the cylinder before the regulator is attached.
As a general rule, repairs to the oxygen cylinder valve should not be attempted by the user, but the cylinder, if in a leaky condition, should be returned to the manufacturer for repair.
Acetylene Generation - Acetylene gas is produced by allowing carbide to come into contact with water. The process of manufacture is so very simple that apparatus not meeting the requirements of safe and pure generation has been common. Lately, how- ever, these poor generators have been very much in the minority and very few are now sold. A generator which will deliver reasonably pure gas safely must be built with the following requirements: A capacity of one gallon of water for each pound of carbide; means to prevent a pressure greater than 15 pounds to the square inch; automatic control of feed mechanism; water valve to prevent return of flame into the generator; filtering or screening devices to prevent dust or dirt getting into the flame.
These are but a few of the proper requirements of a good generator. The National Board of Fire Underwriters' rules specify in detail how the generator shall be constructed. It is hardly necessary to add that any user should see that his generator is built in accordance with these specifications.
Dissolved Acetylene - Dissolved acetylene, or as it is more commonly called tank acetylene, is in wide use by all classes of users. Here gas is bought in ready-made form, ready for use by the opening of a valve. Care is exercised by the manufacturer of dissolved acetylene to purify it before it is compressed into the cylinder. These cylinders vary in size according to the needs of the user, from 100 cubic feet capacity to 500 cubic feet capacity.
Since acetylene is dangerous under pressure in a free state, the method of eliminating this hazard is interesting. The cylinder is filled with a porous material and then ace- tone, a very volatile liquid, is poured into the cylinder. This acetone absorbs the acetylene and as there is no free space in the tank there is no danger in handling or using acetylene furnished in this way.
Care of Acetylene Cylinder - Since the acetylene gas is dissolved in acetone it should not be withdrawn from the tank at a rate fast enough to bring out with it this liquid, which is harmful in its effects on molten metal. The flame used should not require an acetylene consumption at a rate greater than one-seventh the capacity of the tank per hour, that is, a 100-foot cylinder should last 7 hours.
It is for this reason that steel welds made with acetylene from an automobile lighting cylinder are so often unsatisfactory. The gas in automobile cylinders costs more than that in regular size welding tanks and except in emergencies the automobile cylinder should not be used. If it is necessary to employ these cylinders instead of welding cylinders, it is advisable to connect three or four on a manifold to eliminate the possibility of the withdrawal of the acetone.
Acetylene cylinders, when full, should be kept away from any excessively hot place, since the pressure in the cylinder will double as the temperature is doubled. When the cylinder is exhausted of its gas the valve should be closed, for it must be remembered that the tank still contains acetone which will evaporate with the valve open and it will do this especially quick if the cylinder is in a warm place.
Regulators - An essential part of the welding equipment is the regulator. Successful welding demands that the two gases be delivered to the torch in- unvarying proportions and it is the duty of the regulator to reduce the pressure of the gases in the cylinder to the desired using pressure. In principle, all regulators are alike. A diaphragm is interposed between the cylinder pressure and a spring, and when the pressure in the body of the regulator exceeds the tension of the spring, the diaphragm is pushed out- ward, overcoming the spring tension. Attached to the diaphragm is a seat or plunger, varying in design with the different types, which closes the inlet from the cylinder, as the spring tension is so overcome.
Creeping Regulators - A regulator "creeps" when the seat does not close against the inlet nozzle, allowing the gas from the cylinder to enter the body of the regulator beyond the pressure desired. A creeping regulator is detected by the low pressure gauge, the one over the body of the regulator, the dial of which is calibrated in pounds up to fifty or seventy-five. With the valves on the torch closed, the hand on the dial does not remain stationary, but indicates a higher pressure than it did while operating the torch. A creep of a few pounds is allowable, but when it is ten or fifteen or twenty pounds beyond the operating pressure, the use of the regulator becomes a menace, since the pres- sure may become great enough in the body of the regulator to burst the diaphragm or the gauge with considerable force, if there is no safety of an approved design.
The user then should become acquainted with his regulator and be able to renew the seat when required, In the type illustrated the back cap, which is in the form of a square nut, may be screwed off, exposing three screws which hold the seat retainer to the yoke. After these screws are taken out, the seat may be examined and if in bad condition, it may be turned over and the other side used; or if both sides are in poor shape, a new seat may be put in.
DOWNLOAD FREE WELDING BOOK:
Automobile welding with the oxy acetylene flame
A workman in any line must have a knowledge of the tools he uses. The operator of the oxy-acetylene flame must understand the principles of his apparatus to avoid serious errors. Knowledge of the gases used, as well as an understanding of the regulators, torch, supplies and shop equipment, is essential to an intelligent application of the flame.
Oxygen Supply - Tank oxygen is today in universal use by oxy-acetylene shops. There is no method of producing it on any small scale which will compete in cost with it. When we specify tank oxygen, we mean that purchased in seamless drawn cylinders under a pressure of 1,800 pounds to the square inch.
The oxygen purchased in this form is produced by two different methods one by the electrical decomposition of water, which consists of two parts of hydrogen and one of oxygen. By this method, which is termed the electrolytic process, the water is decomposed into its constituents and the oxygen after being led into a gasometer is from there pumped into a steel cylinder under pressure. The other process is known as the liquefaction system. The air, which consists of four parts nitrogen and one part oxygen, is frozen. When the air reaches this liquid condition, the nitrogen boils off first, leaving the oxygen, exactly the same as if gasoline and oil were mixed together and placed in an open vessel, the gasoline would first evapor- ate. The oxygen is then led to the gasometer and from there pumped into a steel cylinder ready for shipment.
Both methods produce a commercially pure oxygen with practically no difference between them for welding purposes.
Care of Oxygen Cylinder - Oxygen is a non-combustible element. It will not burn, but it is the supporter of combustion without it nothing will burn. Obviously, some care must be used, since its escape from the cylinder in the vicinity of sparks, a flame or any greasy or oily substances, may be hazardous.
Oxygen is usually supplied in a cylinder with a narrow base which is easily tipped over unless some precautions are used to guard against this. If a truck is employed, the tank is chained or strapped to the truck. If the cylinder is used without a truck it should never be left standing without support, but should be clamped to the wall or the bench, and where this is not possible it should be placed in a horizontal position on the floor. Regulators are sometimes destroyed by the oxygen cylinder being tipped over and care should be taken to prevent this.
Since oxygen is the supporter of combustion, particular caution must be exercised not to oil or grease any part of the oxygen supply line, particularly the outlet of the oxygen tank valve or the oxygen regulator. If any grease is present with oxygen under a high pressure there is an ideal condition for spontaneous combustion and a violent explosion may result.
Due sometimes to natural conditions, but at others to carelessness, considerable water may be present in the cylinder. This water will damage the regulator and as well adversely affect the welding flame. At intervals it is advisable to test cylinders by tipping them upside down and opening the valve slightly to detect the presence of any considerable volume of water. This method will expel the water from the cylinder before the regulator is attached.
As a general rule, repairs to the oxygen cylinder valve should not be attempted by the user, but the cylinder, if in a leaky condition, should be returned to the manufacturer for repair.
Acetylene Generation - Acetylene gas is produced by allowing carbide to come into contact with water. The process of manufacture is so very simple that apparatus not meeting the requirements of safe and pure generation has been common. Lately, how- ever, these poor generators have been very much in the minority and very few are now sold. A generator which will deliver reasonably pure gas safely must be built with the following requirements: A capacity of one gallon of water for each pound of carbide; means to prevent a pressure greater than 15 pounds to the square inch; automatic control of feed mechanism; water valve to prevent return of flame into the generator; filtering or screening devices to prevent dust or dirt getting into the flame.
These are but a few of the proper requirements of a good generator. The National Board of Fire Underwriters' rules specify in detail how the generator shall be constructed. It is hardly necessary to add that any user should see that his generator is built in accordance with these specifications.
Dissolved Acetylene - Dissolved acetylene, or as it is more commonly called tank acetylene, is in wide use by all classes of users. Here gas is bought in ready-made form, ready for use by the opening of a valve. Care is exercised by the manufacturer of dissolved acetylene to purify it before it is compressed into the cylinder. These cylinders vary in size according to the needs of the user, from 100 cubic feet capacity to 500 cubic feet capacity.
Since acetylene is dangerous under pressure in a free state, the method of eliminating this hazard is interesting. The cylinder is filled with a porous material and then ace- tone, a very volatile liquid, is poured into the cylinder. This acetone absorbs the acetylene and as there is no free space in the tank there is no danger in handling or using acetylene furnished in this way.
Care of Acetylene Cylinder - Since the acetylene gas is dissolved in acetone it should not be withdrawn from the tank at a rate fast enough to bring out with it this liquid, which is harmful in its effects on molten metal. The flame used should not require an acetylene consumption at a rate greater than one-seventh the capacity of the tank per hour, that is, a 100-foot cylinder should last 7 hours.
It is for this reason that steel welds made with acetylene from an automobile lighting cylinder are so often unsatisfactory. The gas in automobile cylinders costs more than that in regular size welding tanks and except in emergencies the automobile cylinder should not be used. If it is necessary to employ these cylinders instead of welding cylinders, it is advisable to connect three or four on a manifold to eliminate the possibility of the withdrawal of the acetone.
Acetylene cylinders, when full, should be kept away from any excessively hot place, since the pressure in the cylinder will double as the temperature is doubled. When the cylinder is exhausted of its gas the valve should be closed, for it must be remembered that the tank still contains acetone which will evaporate with the valve open and it will do this especially quick if the cylinder is in a warm place.
Regulators - An essential part of the welding equipment is the regulator. Successful welding demands that the two gases be delivered to the torch in- unvarying proportions and it is the duty of the regulator to reduce the pressure of the gases in the cylinder to the desired using pressure. In principle, all regulators are alike. A diaphragm is interposed between the cylinder pressure and a spring, and when the pressure in the body of the regulator exceeds the tension of the spring, the diaphragm is pushed out- ward, overcoming the spring tension. Attached to the diaphragm is a seat or plunger, varying in design with the different types, which closes the inlet from the cylinder, as the spring tension is so overcome.
Creeping Regulators - A regulator "creeps" when the seat does not close against the inlet nozzle, allowing the gas from the cylinder to enter the body of the regulator beyond the pressure desired. A creeping regulator is detected by the low pressure gauge, the one over the body of the regulator, the dial of which is calibrated in pounds up to fifty or seventy-five. With the valves on the torch closed, the hand on the dial does not remain stationary, but indicates a higher pressure than it did while operating the torch. A creep of a few pounds is allowable, but when it is ten or fifteen or twenty pounds beyond the operating pressure, the use of the regulator becomes a menace, since the pres- sure may become great enough in the body of the regulator to burst the diaphragm or the gauge with considerable force, if there is no safety of an approved design.
The user then should become acquainted with his regulator and be able to renew the seat when required, In the type illustrated the back cap, which is in the form of a square nut, may be screwed off, exposing three screws which hold the seat retainer to the yoke. After these screws are taken out, the seat may be examined and if in bad condition, it may be turned over and the other side used; or if both sides are in poor shape, a new seat may be put in.
DOWNLOAD FREE WELDING BOOK:
Automobile welding with the oxy acetylene flame
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