1012 



TIN-PLATES 



1995 



quicker than the iron. If this were neglected the face of the plate would be cracked. 

 The plate is removed to the cold pot (No. 5): this is filled -with tallow, heated to a 

 comparatively low temperature. The use of the grease-pots, Nos. 4 and 5 is the pro- 

 cess adopted in practice for annealing the alloyed plates. The list pot (No. 6) is 



used for the purpose of removing 

 a small -wire of tin, which adheres 

 to the lower edge of the plate in 

 all the foregoing processes. It 

 is a small cast-iron bath, kept 

 at a sufficiently high temperature, 

 and covered with tin about one- 

 fourth of an inch deep. In this 

 the edges of the plates are dipped, 

 and left until the wire of tin is 

 melted, and then detached by 

 a quick blow on the plate with a 

 stick. The plates are now care- 

 fully cleaned with bran to free 

 them from grease. Lastly, they 

 are taken to the sorting-room, 

 where every plate is separately 

 examined and classed, and 

 packed in boxes for market as 

 hereafter described. 



The tests of quality for tin- 

 plates are ductility, strength, 

 and colour. To obtain these, the 

 iron must be of the best quality, 

 and the manufacture must be 

 conducted with proportionate 

 skill. This necessity will ex- 

 plain to some extent the cause 

 why nearly all the improvements 

 in working iron during the past 

 century have been either origi- 

 nated or first adopted by the tin- 

 plate makers, and a sketch of 

 the processes used at different 

 times, in working iron for tin- 

 plates, will be, in fact, a history 

 of the trade. 



The process of preparing the 

 best or charcoal iron seems to 

 have undergone but little change 

 from 1720 to 1807. The finery, 

 the chafery, and the hammer, 

 were the modes of bringing the 

 iron from the pig to the state 

 of finished bars. The finery was 

 of the exact form of the fgs. 

 1995, 1996, 1997, but less in size 

 than those now used. Tho 

 chafery or hollow fire was, in 

 fact, the same as the pn 

 smiths' forgo fire, but on a I;U-;L< r 

 scale ; and the ' hollow,' or 

 chamber, in which the bloom 

 was heated, was made by coking 

 the coal in the centre with the 

 blast, and taking care not to 

 disturb the mass of coal above, 

 which was used to reverberate 

 the heat produced. Both the finery and chafery were worked by blast. 



The hammers were of two descriptions : the forge hammer, a heavy mass for 

 shaping the blooms, and the tilt hammer, much lighter and driven quicker, for shaping 

 the bars. 



The charge for the finery was about 1 $ cwt. of pig-iron ; this, under the first 



