TOOLS AND SUPPLIES; FUNDAMENTAL PROCESSES 237 



When the metal is clean, apply the flux to all surfaces 

 which will come in contact, join these as planned and run 

 the soldering iron over or against the joint. 



208. The Soldering-iron, which is made of copper, 

 must be "tinned" to serve as a solder carrier. Fig. 261 

 shows the shape of a soldering-iron. The end is kept filed 

 to form well defined edges and a point. When thoroly 

 clean, heat and rub on solder, then wipe with a cloth, a piece 

 of felt serving the purpose very well. 



To use the soldering-iron heat it in a clean fire, using a 

 gasoline torch, a blacksmith's forge, or a tinsmith's gas 

 forge, and place it against a bar of solder, when a little will 

 adhere to the soldering-iron. 



Another method of using the soldering-iron is to provide 

 an open-mouthed bottle of chloride of zinc fluxing solution 

 and when the iron is heated, dip the point of it into the so- 

 lution to clean it. Then place the iron against the bar of 

 solder, and if properly heated a little solder will adhere to it. 

 This is the customary method of tinsmiths. Fig. 261 shows 

 an open-mouthed bottle of the fluxing solution, together with 

 a can of cleaning material, a block of sal ammoniac and a 

 wiping rag. The Bunsen burner shown in this picture is 

 frequently used to heat the tinner's iron when gas is avail- 

 able. 



The iron is now run on the joint and the solder which the 

 iron holds will fill the joint, cool, and effect a union of the two 

 pieces of metal. The bar of solder is used to hold the tin 

 in position. In case a long joint is to be made, the iron may 

 be run slowly against the metal with the bar of solder held 

 against the iron. The solder will thus melt, run down and 



