128 Modern bi^acksmithino 



for this purpose and in such a shape that the head will 

 break at a high strain. This done use the calking 

 iron all around the patch. 



The patch should be put on the inside of the boiler, 

 especially if on the bottom of a horizontal boiler. If 

 the patch is put on the outside in this place the sedi- 

 ment or solid matter which the water contains will 

 quickly fill up over the patch and there is danger of 

 overheating the boiler and an explosion may follow. 



HOW TO PUT IN FLUES 



The tools necessary to retube an old boiler are, first, 

 a good expander of the proper size ; a roller expander 

 preferred; a crow foot or calking iron, made from good 

 tool steel. A cutting-off tool can be made to do very 



i 



TUBE TO BE WELDED 



good service, in the following manner: Take a piece 

 of steel, say 3^ x i}^, about ten inches long. Draw one 

 end out to a sharp point and bend to a right angle of a 

 length just enough to let it pass inside of the flue to be 

 cut. A gas pipe can be used for a handle. In cutting 

 the flues set this tool just inside the flue sheet and 

 press down on the handle. If this tool is properly 

 made it cuts the old flues out with ease. After both 

 ends have been cut the fl.ues will come out. 



