Archived posting to the Leica Users Group, 2006/01/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi Alex, BMW use aluminium alloy wheels not magnesium. The whole thread started when camera manufacturers started putting magnesium cladding on their plastic bodied cameras to make it more acceptable to market expectation - even though plastic - polycarbonate - is certainly a more suitable shell material for a camera than magnesium. Many people learned to think all plastic items are bad - probably because of badly chosen for purpose plastics in the early days of the technology. Unfortunately the best plastics are very much too expensive to use in cameras. Frank On 20 Jan, 2006, at 20:59, Alex Hurst wrote: > Frank Dernie writ in part: > >> Hi Douglas, >> It is true that very few metals are the used as the pure element, >> AFAIK, and certainly the metals I use, are all alloys. Ally wheels >> for cars are mainly aluminium, though there is a small percentage >> of magnesium and other alloying elements. Ferrari use magnesium >> wheels on their road cars but they have to be immediately surface >> treated and repainted to avoid corrosion if scratched. "Ally" >> wheels corrode readily if used on salt de-iced roads, unless >> painted, but not as fast or badly as magnesium. > >> Aluminium alloys are significantly stronger than magnesium alloys >> but the low density of the latter affords higher specific strength >> and stiffness. Magnesium alloys also possess good machinability >> and can be readily welded using TIG. Having said that they are >> extremely soft and a "bulk" penalty must be paid as a large volume >> of material is required to achieve equivalent properties to other >> structural metals. Furthermore they are expensive and their >> resistance to corrosion is not as good as that of aluminium alloys. >> ed in sheet fabrication processes. > > > For both personal, and economically practical reasons, I am loath > to part company with my immaculate '89 BMW 530i SE (157,00 miles > +). It has mag/alloy wheels, which have never caused a moment's > corrosion problem. Somehow I don't think BMW would have ever > marketed the car if it were subsequently going to melt down on its > tyres. > > Funnily enough. all my Leicas, M2 to M6, don't have any problems > either. But then they haven't been left out in Irish rain for 16 + > years. > > Seems to me that good car manufacturers expect a lot of rain on > their products, but good camera manufacturers don't. > > The only camera (which I have) which would probably survive this > test is the Nikonos. > > What it all boils down to is that there are horses for courses. The > problem with metallurgical arguments is 'what do you do with > plastic?' :-) > > In other words, the whole thread is not exactly relevant (IMHO). > > Best > > Alex > > > > > > > -- > Alex & Carmel Hurst > Waterfall > Near Cork > Ireland > > Tel: +353 21 454 3328 > Mobile: +353 87 245 7048 > Work: +353 21 427 0907 > email: corkflor@iol.ie > Home Pages: http://www.iol.ie/~corkflor > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information