I30 MODERN BLACKSMITHING 



on the other, run through the flue will be found handy 

 for holding the pipes or flues together. In welding 

 these together don't take them out of the fire and 

 strike with a hammer, but take a rod ^-inch round, 

 and bend one end to serve as a hammer. Strike with 

 this hammer lightly over the lap, at the same time 

 turning the flue around in the fire. Use borax to pre- 

 vent the flue from scaling and burning. 



FOAMING IN BOILERS 



There are many reasons for foaming in boilers, but 

 the chief reason is dirty water. In some cases it is 

 imperfect construction of boiler, such as insufficient 

 room for the steam and a too small steam pipe or dome. 

 When a boiler is large enough for the steam and clean 

 water is used there is no danger of foaming. When 

 more water is evaporated than there is steam room or 

 heating surface for, then the boiler will foam. When 

 a boiler is overworked more steam than its capacity 

 will admit is required, and the engine is run at a high 

 speed, the steam will carry with it more water than 

 usual. 



When a boiler foams shut the throttle partly to 

 check the outflow of steam and lessen the suction of 

 water, because the water is sucked up and follows the 

 sides of the dome up. 



If the steam pipe in the dome sticks through the 

 flange a few inches the water will not escape so easy. 

 A boiler that is inclined to foam should not be filled 



