The object of tinning copper stewpans is to prevent chemical action on the copper, which may be injurious to health. It also gives a much better appearance to copper cooking utensils, besides facilitating their being kept clean. To ensure success in re-tinning, the article must, be perfectly free from grease or dirt - in fact, it must be chemically clean. For this purpose, first burn off all grease and dirt over a forge fire or with a blow-pipe until the article is heated to a dull red colour, being particular where the handles are riveted on. Now wipe out the inside with a small pad of tow, and set down to cool, and when cold, thoroughly scour the inside with wet rough sand or powdered coke until it becomes clean and bright. If the dirt has eaten into the metal, or if the surface is very black, wash it with raw spirit of salts (hydrochloric acid), using a piece of tow tied to the end of a short stick. Rinse with cold water, and then scour bright. When perfectly bright, wash the article well with cold water, taking care that no grit or sand remains inside, and then dust the inside with powdered sal-ammoniac. The outside must be prepared by coating it with a mixture of salt and whiting, which should be of the consistency of cream; this prevent s any tin adhering to the outside.

If the top of the outside requires to be tinned to the depth of about l in., as is the case with all new stewpans, it should be thoroughly cleaned as before explained. A band of tin 1 in. deep should be tightly held round the top of the stewpan, while the mixture of salt and whiting is rubbed over the stewpan below the band. Now remove the band, and dust the bright surface of the stewpan, formerly covered with the tin band, with sal-ammoniac. A rubber, by which the molten tin is manipulated over the copper surface, is made as follows. Coil the end of a piece of 1/4-in. wire, about 18in. long, until it is about 2in. in diameter, and tin the coil by soaking it in raw spirit of salts for some time, and then dipping it in a saturated solution of sal-ammoniac and killed spirit (chloride of zinc), and rubbing whilst hot on block tin or tinman's solder. Pla^e thestewpanov ra forge fire, and in it drop a small qua n-tity of pure block tin; the amount of tin depends on the size of the vessel. The tin will soon melt, after which it must be rubbed over the copper with the rubber until the surface of the copper alloys with the tin. Any difficulty in getting this result may be overcome by repeatedly and alternately dusting with powdered sal-ammoniac and Vigorously rubbing over the tin with the rubber.

The top of the outside of the pan may be more easily tinned with a soldering iron, the solution of sal-ammoniac and chloride of zinc being used instead of the powdered sal-ammoniac. Care should be taken that the article is not allowed to get too hot. The maximum heat is obtained when the molten tin can be rinsed round the inside of the article. The molten tin is then quickly emptied out into another pan, if more than one is to be tinned, and the pan quickly wiped out with a pad of clean tow, which will remove any superfluous tin, after which it must be suddenly plunged into a vessel of cold clean water, and then dried by rubbing with clean hot sawdust. When pouring molten tin from one pan into another, great care should be taken in seeing that the pan into which it is to be poured is perfectly dry and warm, otherwise the possibility of the tin flying will make the operation highly dangerous. If a stewpan, ladle, spoon, or strainer requires to be tinned all over inside and out, it should be thoroughly cleaned, and the inside and outside should then be treated with saturated solution of sal-ammoniac and killed spirit of salts, and then dusted over with powdered sal-ammoniac. A vessel containing molten tin should now be in readiness, into which the article should be carefully plunged and washed.

The article is then wiped with tow, plunged in cold clean water, dried with hot sawdust, and polished with whiting.