MODERN BLACKSMITHING 129 



Next, cut the tubes about ^ of an inch longer than 

 the flue sheet. After the tubes are cut the proper 

 length, and placed in the boiler, expand the same in 

 both ends with a flue expander. After the flues are 

 expanded until they fit the holes solid, tuin them over 

 with the peen of a hammer to make them bell shaped. 

 Now take a crows-foot, or calking tool, and turn the 



TUBE EXPANDER 



ends in a uniform head and tight all around. If the 

 flues should leak, and there is water on the boiler take 

 a boiler expander and tighten them up. But never 

 attempt to tighten a flue with the hammer if there is 

 water on the boiler. 



HOW TO WELD FLUES 



In welding flues or putting new tips on old flues, you 

 must find out how far the old tubes are damaged, and 

 cut that part off. Next clean the scales off in a tumb- 

 ling box; if you have none, with an old rasp. 



Now take a piece of tubing the size of the old, and 

 scarf the ends down thin, the new tube to go over the 

 old and drive them together. In welding a rest can be 

 made in the forge to push the tube against while weld- 

 ing, to prevent the pieces from pulling apart. A 

 three-eighths rod, with thread on one end and a head 



