THE HANDY MAN ON THE FARM. 855 



Welding. 

 This is often looked upon as a most difficult operation, and one which can 

 only be satisfactorily performed by an experienced smith. Whilst most 

 men are ready to do many of the rougher kinds of forge work, few care to 

 attempt welding. In many cases this is due to failure in attempts made 

 when the underlying principles have not been understood. If the why and 

 wherefore are not known, attempts at welding arc gropings in the dark, 

 and the rare successes due merely to chance. 



To obtain a good weld, the first requirement is to secure the right heat in 

 both pieces. Where iron is to be welded to iron or mild steel, this is compara- 

 tively easy. Other kinds of metal are more difficult to weld and require 

 some skill. If the pieces of iron are of unequal size, care must be taken 

 that the smaller is not overheated. This can be done by starting one before 

 the other, or, if one shows greater heat than the other, by taking the hotter 

 -out to cool a little. 



When iron and mild steel are heated they gradually change from a hard 

 condition into a softer state. When a certain temperature is reached they 

 become pasty, and if two pieces in a like condition are brought into contact 

 a certain stickiness is noticeable. This is the right welding heat. It is only 

 metals like iron and steel, which become slowly softer before passing into a 

 molten condition, that can be welded. Some cannot be. Lead, as an example, 

 passes suddenly from a hard condition into a molten state without anv 

 perceptible intermediate stage. 



A further essential to a good weld is that the iron is thoroughly heated 

 right through, and not merely superficially. A comparatively slow fire is 

 required to obtain this. If heating is done too rapidly, only the outer surface 

 is heated, and when the iron is taken from the fire it rapidly cools, so that 

 the time required to form the weld is not available. Perhaps the best rule 

 to follow is to heat slowly and notice when the metal comes into the stickv 

 condition shown when the two pieces touch each other. If the iron is too 

 cold welding of course cannot be done, while if the temperature is taken too 

 high, burning will occur and the iron become crumbly. 



A clean lire is required. In a dirty fire pieces of clinker, cinder, &c, 

 adhere to the metal and, getting in between the two pieces, cause flaws in 

 the weld. As mentioned before, the fire must also consist of compact burning 

 coke, fed with the right amount of air. 



Everything must be in readiness to proceed at once when the iron is 

 sufficiently heated. When it is taken from the fire it cools rapidly, and no 

 time must be lost. The anvil should be clean, and all tools at hand, so that 

 they can be picked up without even looking for them. 



Different forms of welds are used according to the nature cf the work. 

 Each differs in some respect, and different methods of preparing for the 

 weld are adopted. The main preparation consists of upsetting and scarfing. 

 The hammering when welding tends to reduce the thickness of the iron at 

 that particular point, and to compensate for this both pieces of the weld 

 must be upset as described a few pages further on. 



Scarfing is the thinning down, with the hammer, of the tips of the parts to 

 he welded, so that they will fit together and weld without much hammering. 

 A more perfect weld is obtained, and less drawing down will be required to 

 (finish up the work after welding. 



