Lorn Campbell

“ At the present time only such metals as steel and wrought iron can be successfully cut. When it comes to cast iron no method has yet been discovered to cut it with any degree of success by the oxy-acetylene flame, on account of the high melting-point of the oxide and various other matters. The day is looked forward to, however, when after sufficient time and study has been devoted to this subject, that cast iron can be as successfully cut as any other metal, by introducing another gas or agent to destroy some of the reactions which retard its application at the present time. ”

“ In order to know how to weld, it is quite imperative that the operator first know the kind of metal he is to work on. It is surprising to find how few welders know their metals thoroughly. An incident might be cited where some welders depend upon the sparks given off by the emery wheel in determining the kind of metal they are about to weld. They will approach the wheel; grind off their work, noting the sparks; return to their welding table; choose their filler rods and do their welding without any delay whatsoever, much to the consternation of their fellow workers. ”

“ Now, if there is a fracture and a foreign metal, which under no circumstances can be expected to take the same hardening as the rest of the spring, is introduced into the weld, it can easily be seen why a fusion of this kind is not to be relied upon. If it were possible to diagnose or take an analysis of the metal in the spring and use a filler-rod which, after being acted upon by the flame, would come out the same as the metal in the spring, then some success might be expected, but until that time, welding of springs will not be encouraged. ”

“ It is singular indeed that a school manual, devoted exclusively to the instruction of the beginner, which will serve as an aid to the instructor as well as to the student, has not yet been put forth. It cannot be said that there is not a demand for such. Recently there seems to have been a mushroom growth of welding classes. The majority of the vocational schools, colleges, night schools, and automobile schools have all entered the instruction in oxy-acetylene welding on their rolls and each is attempting to instruct in an entirely different manner from the other. ”

“ There are those who consider carbon burning injurious to the motor on account of the high temperature flame [139] which they think is introduced. But it is ignorance as to the working principle of this process that makes them think this. When it is considered that a gasoline motor depends upon a rapid succession of internal explosions for its power, the folly of condemning a process of this nature, where absolutely no actual flame is used, will be seen. ”

“ The cost of such is only of secondary importance, the hazard attached to cheaply constructed apparatus and the loss of gas, time and the execution of faulty work and the depreciation of the welder’s reputation, are matters of vital importance. The supplies too, such as filler-rods and the like, should be obtained only from reliable welding companies who have their own shops in which they may test them. It is false economy indeed, to attempt to save a few cents on filling materials, for many dollars’ worth of time and gas may be lost on account of the failure of the metal added. ”

“ In welding over head there is a tendency on the part of most welders to avoid the use of enough heat to bring their metal to a molten state, for fear that it will drop upon them. It must be remembered that lack of heat means poor welds and that the metal must be in a molten condition whenever the weld is to be made. As soon as a little practice is given to this kind of work, the welder will see that the melted metal can assume some proportions without dropping off, despite its weight. ”

“ In oxy-acetylene welding there are two gases used, as the name would indicate, namely, oxygen and acetylene. The first is used to intensify the flame and can in nowise be likened to the inflammable nature of the second. There is a great deal of oxygen present in the air we breathe. It is an odorless, tasteless, and colorless gas, as most of us are aware. In the commercial world oxygen is manufactured by the decomposition of water into its elements, oxygen and hydrogen, by the electrolytic process or is taken from the air by a reduction process and is stored in steel-drawn cylinders. ”

“ It is considered best, if possible, in attempting carbon burning for the first time, to try it on some motor which is about to be overhauled, in order that the results may be studied so that the operator will not go blindly on, without showing some improvement. Many times only the high points are burned out, which will free the motor temporarily of some of its knocks, but within a week or so they will become evident again. He who will become proficient in learning carbon burning should apply himself and study his results. ”

“ It is probably safe to say that the principal cause of hard spots in steel welds is due to lack of heat. This, if given careful thought and consideration, will be brought home forcibly to the welder as he proceeds in his work, for the lapping of metals, trapping of oxides, “craters,” too rapid cooling, etc., may all be directly attributed to a lack of sufficient heat. If the metal is in a molten state, all impurities will be brought to the surface, for they are bound to be displaced by the weight of the metal, the same as corks in a barrel will float to the top if water is introduced. ”

“ It is difficult for the beginner to accustom himself to brass welding, especially on large work. While he has been taught to believe that brass has a much lower melting-point than iron or steel, yet when he comes face to face with the actual problem of melting it, he will find that it is necessary to hold his flame in contact with his piece much longer, on brass work than on either of the other two, before the melting point is reached. ”

“ Another important item which is generally overlooked in the average welding shop is the question of ventilation. Although the welding flame itself contains no objectionable gases, those from fresh charcoal preheating fires, those given off when some of the alloys of the filler-rods are melted when brass, copper, and other metals are being worked on, and from gas engine exhausts are not desirable. At times they will give the operators violent headaches unless means are taken to carry them off. ”

“ It is well to learn how to make a successful weld from one side of the metal only, and while this will apply to all metals, it is especially advantageous in working aluminum. Where a small layer of metal has been added to one side of an aluminum job, such as a crank case, and it does not penetrate the entire thickness of the metal, when the other side is turned, and the flame applied to it, a difference in temperature and the loss of strength in this metal when heated will cause the first side welded to crack unless the operator is extremely cautious. ”

“ The ease with which aluminum is puddled together, which many welders have likened to the children’s method of making mud pies, seems so simple to the beginner that he cannot see where the strength comes from when cooled. On account of this, he invariably works his aluminum too long. After welding a few test bars of this metal and breaking them in the line of weld, many old welders will gain confidence upon seeing the results of their own efforts. ”

“ The matter of heat in malleable iron is of considerable importance. If not enough heat is used there will be no fusion between the bronze and the iron, whereas on the other hand, if too much heat is used, the bronze will not adhere, but will seem to boil on the surface and form in small globules rather than spread over the whole metal. ”

“ It cannot be expected, however, that a steel with the same cross-section as the original will possess the same properties and be as strong, for a weld is only a casting unless treated otherwise and the steel or wrought iron used in the specimens is of rolled stock. If too much metal has been added and dressing down is necessary, the student will find that by using a slightly oxidizing flame the surplus metal can be burnt away very rapidly and a very good-looking job can be executed much more rapidly than if a neutral flame were used. ”

“ In welding cast steel the same procedure takes place as previously described for steel, and it should present no real difficulties after that process is understood. There may be more sand, oxide and other impurities present on account of the nature of the metal, but these can all be worked out if plenty of heat is applied. At times, when working in steel, it will be found that there may be a small hole develop in the center of the weld and as the torch is worked into this hole it is found that it goes down a short distance and seemingly refuses to be worked out. ”

“ Acetylene gas, when burned with a proper portion of oxygen gas, produces an extremely hot flame, in fact, the hottest flame known. Its temperature is over 6000 degrees Fahrenheit. With this flame it is possible to bring any of the so-called commercial metals, namely: cast iron, steel, copper, and aluminum, to a molten state and cause a fusion of two pieces of like metals in such a manner that the point of fusion will very closely approach the strength of the metal fused. If more metal of like nature is added, the union is made even stronger than the original. ”

“ If no extra welding torch is available, a carbon burning torch or any piece of copper tubing which has a valve in one end, suitable for taking a hose connection, and the other end free to have a welding tip brazed on, can be used in the same manner. The welding torch will give the neutral flame and the extra line of oxygen will do the cutting. It is well to remember that oxygen, no matter under what pressure, cannot be expected to act upon cold metal. A red heat is absolutely necessary. ”

“ Leaks on either the oxygen or acetylene lines are to be considered dangerous as well as costly and therefore to be avoided at all times. When the cylinder valves are closed on the drums containing the gases, and the hands on the low-pressure gauges of each regulator are seen to drop or reduce their pressure when the torch valves are shut off and allowed to remain so, this is an indication that there is a leak between the regulator and the torch. It is not desirable to use a match or a flame of any kind in testing for leaks. ”

“ However, as soon as there is heat introduced into the water-jacket and not into the cylinder wall, there are certain to be strains set up which, if sufficient, will distort the cylinder and make it useless unless it is rebored. The sooner welders realize that work of this nature must be preheated throughout, to a point as near melting as they can approach without causing the metal to scale, before any welding is attempted, the better success will be obtained in these lines. It is quite necessary to line up the work well, so that it will not sag when heated. ”

“ The cast iron in the rods is of a very good grade and generally much better than the piece to be worked upon. To permit the ready flow of the rod and eliminate oxidation, as much as possible, three per cent of silica is generally used in the casting of filler-rods for cast iron welding. Piston rings and other scrap iron should not be used for filler-rods, as they contain many impurities such as core-sand, dirt, grease, etc., which will ruin the weld. It is disheartening to see some operators attempt to economize on the filler-rod. ”

“ Remember that the flux is a cleaning agent and if the surface is clean, no additional flux is necessary, but if the contrary is true, that is, if the surface is full of oxide and the filler refuses to flow easily, flux is necessary and should be added. ”

“ When advancing in steel work, it will be noticed that the same provision for contraction and expansion is not considered in as great proportions as on cast iron, and the reason is quite evident. In cast iron we find the metal is very brittle and will not give without breaking, whereas on steel it is more ductile and will twist and bend before breaking. ”

“ To assist the welder in executing welds on large steel castings, the pieces are generally preheated, so that the work will take less time, be more successful, and save both oxygen and acetylene. When working on preheated jobs, in order to get the desired angle on the filler-rod so the welder may use it without discomfort, a light heat is played on the filler-rod, a matter of six or eight inches from the end being fused and then bent to an angle of 90 degrees, so that the operator may hold the rod at some distance from his work and still introduce it in the manner he desires. ”