36 Laboratory Arts 



Soldering Iron. Many kinds of soldering irons are to be 

 obtained, and upon one's personal preference for any particular 

 shape depends the quality of work turned out. The straight 

 type of iron is inconvenient for many purposes, as it is often 

 difficult to see what one is doing with it, and the hatchet type 

 is therefore to be preferred. G. Adams and Co., of 144, High 

 Holborn, list a tool at 2s. $d. of 14 oz. bit (Fig. 24), which may 

 be turned either way, and which is therefore convenient so far 

 as this goes, but it is small, and thus there is a rapid loss of 

 heat which causes much waste of time. The bit should not 

 weigh less than i lb., and it may safely be taken that the 

 heavier the bit, the better the work and more easily is it 

 accomplished. 



Should it be too heavy, however, it will tire the worker, and 

 an unnecessary physical strain will result. Each worker should, 



N 916 



FIG. 24. 



therefore, procure an " iron " of the maximum weight that he 

 can handle with comfort. 



The " bit " of the soldering iron is made of copper, for 

 various reasons 



1. Properly handled it corrodes but slowly. 



2. Solder alloys easily with copper, consequently contact 



with the copper bit aids solder to " flow." 



3. Copper carries a fair quantity of heat from the flame to 



the work, its specific heat being reasonably high. 

 A soldering iron is used for heating work to the point at 

 which it alloys with the solder a mixture of tin and lead in 

 varying proportions. It must, therefore, carry a fair amount of 

 heat, or the tool cools before the work is sufficiently heated, 

 which means the loss of the whole time, for the work cools 

 while the tool is being reheated. 



