No. 2 (1921) REMARKS ON CANNING 53 



(3) solderers, especially in India, work very slowly so that 

 there must be a large staff; this is not always procurable, and 

 among a large staff there are sure to be careless or unskilful hands 

 who may cause heavy losses ; 



(4) a careless solderer not only allows leaks but wastes 

 solder ; this single item, apart from leaks, may swallow up much 

 of the profits on a batch ; 



(5) in processing by pressure steam a weak solder joint may 

 easily give way in the kettle (see elsewhere) or on removal from it, 

 and serious loss may then result ; 



(6) the joint which unites the two ends of the body strip is 

 usually a lap joint, i.e., one end laps over the other about % of an 

 inch and the two ends are united by a large quantity of solder, 

 which, from pin holes, is often a source of weakness. In any case 

 the joint is weak, costly, and ugly. 



38. Consequently — and for other reasons— it has been sought to 

 close cans hermetically wholly without or with a minimum amount 

 of solder. In the Beypore cannery a line of machines has been 

 set up which entirely dispenses with solder, viz., by 'drawing' 

 (pressing) the dish or body of the can from the flat at a single blow, 

 so that a flat piece of tin plate becomes a perfect body without 

 seam of any sort. This dish is flanged by the same blow, and the 

 narrow flange is then trimmed to a proper size in another machine. 

 The second machine also strikes the covers, and a third machine 

 affixes rubber composition rings (washers or gaskets) to the covers. 

 When the bodies are duly packed with fish, they are brought to a 

 fourth machine called a ' double seamer ', the covers are laid on 

 the bodies, and the machine then clamps the cover and body 

 together in a seam by turning the edge or rim of the cover under 

 the lower edge of the flange of the body — the rubber washer being 

 between them — and then forcing the two flanges together in a 

 hermetical joint. The result, if the double seamer is properly 

 adjusted, is a perfectly sealed can without a particle of solder, with 

 only the one seam, viz., that which unites the body and the cover, 

 and consequently with less chances of leakage than in the soldered 

 cans. The machines can be provided with different dies and 

 chucks so that cans of various shapes (round, rectangular, oval) 

 can be made and closed in them. The Beypore plant has a set for 

 quarter tins and for medium ovals. Similar tins of small size and 

 shallow, such as those used for boot polishes, medicines, samples, 



2-A 



