Gilding brass

John Champion patented in 1758 the process of producing brass and zinc from the common ore of zincblende (ZnS) or black jack (patent number 726). This ore had previously been considered worthless, but even with this advance it is obvious that metallic zinc was still far too expensive to use in brass production by direct mixing, a process which was patented by James Emerson in 1781 (no. 1297). Watson (1786), however, describes the use of zinc in the production of high-quality gilding brasses such as pinchbeck, tomback and Mannheim gold (see below). 

The official alcoholometer is the Sikes hydrometer, which is a gilded brass instrument and is provided with a number of auxiliary weights to allow of its use with spirits pf widely varying strengths, Translator.]... 

The tendency of mercury to combine with gold and silver is made use of in extracting these metals from their ores. An amalgam of 1 part of gold, and 8 of mercury, is used in gilding brass. 

Mercury(I) nitrate is used for preparing calomel and other mercury(T) salts. Other applications are fire gilding and blackening of brass. 

Percussion primers used in current center-fire cartridges (See Ref 44, p C74-L) in US and NATO small arms are shown on Fig 31 is taken from TM 9-1305-200(1961), p 25 (Ref 42). Each of these primers consists of a small brass or gilding metal cup that contains a primer compn pellet. Present compns are mostly noncorrosive type, such as consist ing of LSt-LA. The older types contained usually MF, KCIOj Sb2Sj, with or w/o ground glass and a binder. A paper disk (foil), which serves... 

The components of Navy percussion fuze primers contg MF usually consist of a Cu (or cartridge brass) primer cup, a tin (or Cu) sealing cup or disk, and a tin-plated brass anvil. Cartridge brass and gilding-metal is used by the Army for primer cups contg MF... 

Gilding Metal. Accdg to Gardner (Ref 2) it is a reddish-yellow metal consisting of Cu 70, So 12.5 brass 1 7.5%... 

Gilding metal is used for some military purposes. The requirements of US Armed Forces for gilding metal, called "95/5 Brass 1, are covered by Specification JAN-G-439 (Aug 1946) Cu 94—95 St Zn 6—5% (minus allowable impurities 0.13%, which include Pb max 0.03 Fe max 0.05%). This type of gilding metal is used as casings for primers and detonators for artillery ammunition and bombs... 

There is also gilding metal "98/2 Brass" Refs 1) B. Grotta, ChemMetalEngrg 26, 1132 (1922) (Gilding metal used for detonator casings contd Cu 90 Zn 10%) 2) W. Gardner,... 

Methods of gilding silver, copper or brass are given much as in the more ancient writings. So also solders for gold and silver, though borax is included indicating Arabian influence at the time of this writing. 

The principal military use of brass was formerly for the manuf of cartridge cases (See Vol 2, pC78-R), but now other materials are used, such as steel, plastics and colloided smokeless proplnts. Another Cu alloy, bronze (Cu 90 Sn 10%) was formerly used for casting gun barrels (Ref 13, p 167), but now steel is used for that purpose. The so-called gilding metal (Cu 90 Zn 10%) has been used as a jacket for lead-alloy bullets (See Vol 2, p B327-R, under Bullets, Metal Jacketed)... 

The vast majority of cartridge cases are made of brass (approximately 70% copper and 30% zinc) but other materials such as steel, coated with either zinc, brass, gilding metal, copper, lacquer or blackened copper nickel-plated brass cupronickel (approximately 80% copper and 20% nickel) gilding metal (approximately 90% copper and 10% zinc) aluminum. Teflon-coated aluminum and plastic are also encountered. 

Bullet jacket materials include gilding metal cupronickel cupronickel-coated steel nickel zinc-, chromium-, or copper-coated steel lacquered steel brass nickel- or chromium-plated brass copper bronze aluminum/alumi-num alloy Nylon (Nyclad), Teflon- and cadmium-coated steel (rare). Black Talon bullets have a black molybdenum disulfide coating over the metal bullet jacket which acts as a dry lubricant. Steel jackets are frequently coated both inside and outside as an anticorrosion measure. Gilding metal is by far the most common bullet jacket material. Tin is claimed to have lubricating properties and is sometimes incorporated in bullet jacket material. The alloy is known as Lubaloy or Nobaloy and contains 90% copper, 8% zinc, and 2% tin. 

The tracer composition is frequently housed in a metal canister placed inside the base cavity. Copper, brass, gilding metal, gilding metal-coated steel, and copper-coated steel canisters are known. Some compositions are placed into the hollow base cavity without the use of a canister. A typical tracer bullet consists of a gilding metal bullet jacket and a lead core with a base cavity containing the tracer composition. Paper discs and lead, steel, or brass washers sealed with varnish are sometimes used to seal the base of the bullet. 

Gilding metal "90/10 Brass" consists of Gl 89 to 91 Zd H to 9% (minus allowable impurities)... 

It appears that by the eleventh century considerable pains were being taken to purify copper used in making brass for ornamental purposes. Brass containing lead was difficult to gild, so the removal of this element was important. Rugerus Theophilusf, a monk who lived in the earlier years of the eleventh century, described in detail a method for doing this. The copper was heated in a clay-lined iron dish under charcoal until it melted the liquid was then stirred with a dry stick to which the lead scum adhered. 

Prior to the introduction of rolled gold, imitation jewellery was made chiefly of copper or brass gilded with pure gold the soft gilt... 

Some of the common brasses are yellow, naval, and cartridge brass mimtz metal and gilding metal. The compositions, properties, and typical uses of several of these alloys are listed in Table 11.6. Some of the common uses for brass alloys include costmne jewelry, cartridge casings, automotive radiators, musical instruments, electronic packaging, and coins. 

---