Archived posting to the Leica Users Group, 1997/01/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]D Khong <dkhong@pacific.net.sg> wrote: >> Leica engineers have a good reason for choosing a metal to build the M6s >> out of, and that it is not necessarily the same reasons that Leicaphiles >> prefer brass to zinc (isn't brass an alloy of zinc and some other metal, >> or am I thinking of bronze?). Zinc is not a particularly hard metal, if >> I recall correctly, so I don't think that Leicas will split open if they >> fall. Some people think that if the M3 was brass, then therefore the M6 >> should be brass also, regardless of the actual differences between zinc >> and brass. > Brass is an alloy of Copper and Lead. Bronze (harder than brass) is an > alloy of Copper and Tin. My chemistry teacher made sure we knew the > composition. Neither alloy has a fixed composition, but brass is predominantly copper and zinc, bronze predominantly copper and tin. But there are alloys called "bronze" that have a higher proportion of zinc than a typical brass, and other additives to alloys in the copper-and-other-stuff family may include lead, phosphorus, silicon, aluminium, silver, antimony, iron and presumably eye of newt if it melts at the right temperature. What people may be associating pejoratively with zinc is the alloys used for making toys - these do break very easily, but also don't contain much zinc. High-zinc alloys can be quite hard, tough and corrosion-resistant. > My history teacher reemphasized on the composition of bronze. The bronze > age was part of history. It was eventually superceded by the iron age. > They were able to achieve higher temperatures by that time and were there- > fore able to extract iron out of ore. The warriors with iron weapons were > superior to those wielding bronze ones. Because they had *more* weapons, not better ones. Once the technology was mastered, iron could be produced in vastly greater quantities with less dependence on unusual mineral deposits; iron ore and charcoal are everywhere. > So is it confirmed beyond doubt that the M6 Titanium has a brass body? The interesting question is what kind of brass might be used. Brasses vary enormously in composition and mechanical properties. Could someone kindly strip their M6 and dissolve it in acid to resolve this important question? - ---------------------------------------------------------------------------- jack@purr.demon.co.uk - Jack Campin, 2 Haddington Place, Edinburgh EH7 4AE