| Show enameling iron the articles to be enameled are first subjected to full red heat for half an hour in an annealing furnace and then allowed to cool slowly af after ter which ther their surfaces are scoured clean and bright and freed from all grease then they are ready for the first coat of en enamel am this is composed of six parts by weight weigh t of aln flint t gla gia glass ss t three of borax one of red lead and 1 0 one a of ooyd yd of tin these are pounded together in a mortar and then kept at a strong red head heat in aa a furnace for three erfour or four hours during which period they are frequently stirred t to effectually and expel all volatile matter when partially vitrified fied the whole is withdrawn in a pasty state dropped into cold water and is then easily ground to powder which is called frit 2 with one part of frit is mixed two of bone dust which is ground in a mill until perfectly fine and soft and of the consistency of thick cream when it should be strained a fine cloth the article to be coated is now held over the vessel containing the semi liquid and a suitable quantity poured over it some articles inay may be dipped in the enamel when drained and sufficiently dry as no longer to run they are placed in a aja s stove kept at a heat of degrees until all moisture is expelled defective f places maybe may be filled up with a brush when perfectly dry they are placed in in the vitrifying vitrify ing furnace at a glowing red heat and when the coating is partially fused and it adheres firmly to the metal they are withdrawn and laid on a flat 1 iron ron bench to cool when cold they are wetted with a sponge a second coating given dried and fired as before a different composition being used this consists of thirty two parts by weight of bone sixteen of china clay and eighty eight parts pants arts of potash dissolved in water mixed baked bake and ground in powder to five fiva parts of this powder is added sixteen parts of flint glass five and one half of flint in this second birin firing the articles must be b e kept in the furnace until ile ite the tha second coat is thorough thoroughly aly incorporated with the first the ne articles having been twice coated are again treated with another compo composition composite siti on cen con of four parts by weight of fel fei feldspar ar in I 1 powder four of white sand four of car carbonate g r onate of potash six of borax one of ooyd of tin tiry one of nitre ditre and one of whiting these are frit fretted ted ua ground and made into a creamy paste as before described I 1 jn in firing the we articles for the third time they I 1 must be subject tb such a heat as thoroughly to vitrify the glass to spread over and become i entirely incorporated with it so as completely to glaze the surface A fourth coat may be given it if thou thought ht desirable to give a f full cuil ull uil and j rich enameled covering by these several processes I 1 and by varying the materials of the compositions composition s iron articles may ba be made de t to represent t the he best china either pure white or ornamented in colors and gold or ing with a pure transparent coating in the first attempts to enamel i iron arsenic formed an ingredient in the formation for mation matlon of the enamel but butt was found highly injurious scientific amer ican |
