CHAPTER V

SOLDERING (_Continued_)

PREPARING A JOINT FOR SOLDERING—CLEANING AND SCRAPING—SOLDERING A PRACTICE PIECE—SOLDERING THE HANDLE TO THE BISCUIT CUTTER—A SECOND PRACTICE PIECE—ANOTHER METHOD OF APPLYING SOLDER

=Cleaning and Scraping.=—If the copper is thoroughly tinned and the heater and materials are ready for use as described in Chapter IV, then several practice pieces should be soldered together before attempting a joining on any real work you may have ready to solder.

If the tin is bright and clean, it need not be scraped at the joint where the solder is to go. Rusty spots should be scraped bright if in the path of the solder. Paper, labels or paint must be cleaned away. If a can has been well rinsed with hot water when the contents are emptied, it will present no difficulties to the soldering, but a can that has been emptied but not rinsed presents a more difficult surface to solder; particularly tomato, fruit, or condensed milk cans. This, of course, applies only to the inside of these cans. Tobacco, coffee, cocoa, tea cans and the like offer no resistance to the solder without washing. The yellow lacquer used to line some cans need not be scraped off. Solder will adhere well to tin so treated, but paper, paint, etc., must be scraped from the path of the solder. The scraped part need only be a quarter of an inch in width on each side of the joint; the rest of the paper labels or paint will be removed in the hot lye bath used before painting the can.

The scraping may be done with an old knife, or a regular scraper furnished by the dealer in tinners’ tools as illustrated on page 202,