Part 3 (2/2)
A fine black varnish suitable for the covering of broken places in sewing machines and similar articles, where the japanned surface has beco so it with copal varnish The black must be in a very fine powder, and to mix the more readily it should be made into a pastyshop this will be found very handy
The following is a si The sections as ht wood shavings, and the latter set alight The effect of this treatainst rust for an indefinite period, rendering future painting unnecessary
It is important, of course, that the iron should not bea ti is a varnish for iron and steel given by a recognized authority: 5 parts of camphor and elerains of mastic, are dissolved in the requisite quantity of alcohol, and applied cold
Another good black ena 1 lb of asphaltu the whole in an iron vessel before applying
A good brown japan can be prepared by separately heating equal quantities of a to each one-half the quantity by weight of boiled linseed oil Both coether Copal resin may be substituted for the amber, but it is not so durable Oil varnish hly elastic If it is used to protect tin-plate printing, when the plates after stoving have been subsequently rolled so as to distort the letters, the varnish has in no way suffered, and its surface re iron consists of 120 parts reen vitriol, 120 parts water, and 15 parts hydrochloric acid of 12 specific gravity
SECTION VI
PROCESSES FOR TIN-PLATING
In these days oflook what it is not, perhaps the best and cheapest substitute for silver as a white coating for table ware, culinary vessels, and the , is pure tin It does not co qualities, but it costs very much less than silver, is readily applied, and can be easily kept clean and bright In tinning holloare on the inside theit in diluteit with fine sand It is then heated over a fire to about the -point of tin, sprinkled with powdered resin, and partly filled with rain tin covered with resin to prevent its oxidation The vessel is then quickly turned and rolled about in every direction, so as to bring every part of the surface to be covered in contact with the reater part of the tin is then thrown out and the surface rubbed over with a brush of tow to equalize the coating; and if not satisfactory the operation must be repeated The vessels usually tinned in this manner are of copper and brass, but with a little care in cleaning and , iron can also be satisfactorily tinned by this means The vessels to be tinned must always be sufficiently hot to keep theby contact with am process is not soto the clean and dry a the surface to heat, which volatilizes the latter, leaving the tin adhering to the metal
The i articles of brass or copper When immersed in a hot solution of tin properly prepared the metal is precipitated upon their surfaces One of the best solutions for this purpose is the following:--
A 12-1/2 lb
Protochloride of tin 1 oz
The articles to be tinned hly cleansed, and then kept in the hot solution until properly whitened A better result will be obtained by using the following bath, and placing the pieces in contact with a strip of clean zinc, also immersed:--
Bitartrate of potassium 14 oz
Soft water 24 ”
Protochloride of tin 1 ”
It should be boiled for a fewis one of the best solutions for plating with tin by the battery process:--
Potassium pyrophosphate 12 oz
Protochloride of tin 4-1/2 ”
Water 20 ”
The anode or feeding-plate used in this bath consists of pure Banca tin This plate is joined to the positive (copper or carbon) pole of the battery, while the work is suspended froative (zinc) pole Abattery is required, and the work is finished by scratch-brushi+ng