pico Posted January 6, 2016 Share #1 Posted January 6, 2016 Advertisement (gone after registration) This afternoon I took out my M4-P and out of curiosity I found it was one of the first 1000 made. The top plate appears to be something other than brass. Is it, and if it is not brass than what is it? I'm ready to throw it into the river. . Quote Link to post Share on other sites More sharing options...
Advertisement Posted January 6, 2016 Posted January 6, 2016 Hi pico, Take a look here The M4-P is alloy?. I'm sure you'll find what you were looking for!
earleygallery Posted January 7, 2016 Share #2 Posted January 7, 2016 (edited) Alloy, same as the M4-2 and most M6's, the stuff that's prone to the 'corrosion' pimple/spot issue. Don't throw it away, send it to me if you can't bear not to have a brass top plate! Edited January 7, 2016 by earleygallery Quote Link to post Share on other sites More sharing options...
jdlaing Posted January 7, 2016 Share #3 Posted January 7, 2016 Zinc alloy. Quote Link to post Share on other sites More sharing options...
Matlock Posted January 7, 2016 Share #4 Posted January 7, 2016 Alloy, same as the M4-2 and most M6's, the stuff that's prone to the 'corrosion' pimple/spot issue. Don't throw it away, send it to me if you can't bear not to have a brass top plate! The M4-2 top plates are brass as are the early M4-P top plates. The Zinc Alloy top plates were introduced to overcome the distortion problems found in a few M4-2 brass plates. In spite of the stories of corrosion I have never come across any myself (I have, of course seen pictures and heard stories). The Zinc Alloy top plates were replaced with machined brass which reduced costs and allowed a more flexible production programme. 1 Quote Link to post Share on other sites More sharing options...
adan Posted January 7, 2016 Share #5 Posted January 7, 2016 (edited) Note that the "black" chrome finish required an undercoat of silver chrome or nickel to bond with the brass. Therefore, the brass black-chrome M4-P (and black-chrome M4 and M4-2) covers will shown silvering beneath the chrome as they age, and the chrome overall is so tough that even after 40 years, few will have worn all the way down to the brass itself. M4-Ps with the zinc-alloy M6 cover plates will have the "flush" glued-in windows of the M6, rather than the internally-mounted, recessed windows of the M4-2 and predecessors. Early/Mid M4-P - windows recessed behind metal: http://news.mapcamera.com/media/mapcolle/M4_P_1.jpg Late M4-P - windows flush with exterior: http://farm6.static.flickr.com/5330/7372548888_83b4d80039.jpg Edit: even black M5s show "silver" beneath the black chrome: https://www.cameraquest.com/jpg3/leica_m5_worn01.jpg Edited January 7, 2016 by adan 1 Quote Link to post Share on other sites More sharing options...
duckrider Posted January 7, 2016 Share #6 Posted January 7, 2016 (edited) last 2000 M4-P were zinc, earlier one brass. Here my late one with M6 window: Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! looking onto the top You can see a corrosion spot left top over dial: Edited January 7, 2016 by duckrider Quote Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! looking onto the top You can see a corrosion spot left top over dial: ' data-webShareUrl='https://www.l-camera-forum.com/topic/255307-the-m4-p-is-alloy/?do=findComment&comment=2963999'>More sharing options...
hepcat Posted January 7, 2016 Share #7 Posted January 7, 2016 Advertisement (gone after registration) This afternoon I took out my M4-P and out of curiosity I found it was one of the first 1000 made. The top plate appears to be something other than brass. Is it, and if it is not brass than what is it? I'm ready to throw it into the river. . Yep. It's zinc alloy. Just like my M4-P. And the gear train isn't the same as the M4's either... but it's one of the toughest bodies built and the "best buy" in Leica M bodies. Don't worry about it, pico... just go out and run some film through it! You'll find it makes photos that are the equal of any in the world. 1 Quote Link to post Share on other sites More sharing options...
pgk Posted January 7, 2016 Share #8 Posted January 7, 2016 The M4-2 top plates are brass as are the early M4-P top plates. The Zinc Alloy top plates were introduced to overcome the distortion problems found in a few M4-2 brass plates. In spite of the stories of corrosion I have never come across any myself (I have, of course seen pictures and heard stories). The Zinc Alloy top plates were replaced with machined brass which reduced costs and allowed a more flexible production programme. You might find this interesting: https://en.wikipedia.org/wiki/Zinc_pest - perhaps, if this is the problem occasionally reported, there may have been a contaminated batch produced. I have seen the pitting problem on M6s myself. My father repaired woodwind instruments for a time (he was an engineer and clarinetist) and he dreaded Mazac (a zinc alloy) keywork due to the difficulty in repairing it when broken (new keys usually had to be built from scratch). 1 Quote Link to post Share on other sites More sharing options...
pico Posted January 7, 2016 Author Share #9 Posted January 7, 2016 Don't worry about it, pico... just go out and run some film through it! You'll find it makes photos that are the equal of any in the world. I just put an Abrahamsson Rapidwinder and grip on it. It feels better already. 1 Quote Link to post Share on other sites More sharing options...
nobbylon Posted January 7, 2016 Share #10 Posted January 7, 2016 Remember that in most cases of so called corrosion that it's taken 30 plus years to show a few tiny pimples! Like the M4-p above, it may get another pimple spot in 2046!!! Quote Link to post Share on other sites More sharing options...
sblitz Posted January 8, 2016 Share #11 Posted January 8, 2016 in all the used zinc top Ms I have seen, never one with blisters/corrosion .... i will worry about in 2046 -- presuming i am still alive and aware of what a camera actually is... Quote Link to post Share on other sites More sharing options...
duckrider Posted January 8, 2016 Share #12 Posted January 8, 2016 In 2046 and 30yrs. later M3 from 1954 will not even have ONE pimple spot! But world will be contaminated with more controllers than ever... Thomas Quote Link to post Share on other sites More sharing options...
nobbylon Posted January 8, 2016 Share #13 Posted January 8, 2016 (edited) In 2046 and 30yrs. later M3 from 1954 will not even have ONE pimple spot! But world will be contaminated with more controllers than ever... Thomas In another 30 years M3's will all be unusable due to finder seperation and a lack of technicians with a/ the spare parts and b/ the know how!There will be more chance of toasting bread with your own light saber Edited January 8, 2016 by nobbylon 1 Quote Link to post Share on other sites More sharing options...
duckrider Posted January 8, 2016 Share #14 Posted January 8, 2016 (edited) In another 30 years M3's will all be unusable due to finder seperation and a lack of technicians with a/ the spare parts and b/ the know how! There will be more chance of toasting bread with your own light saber No problem: We can use finder sytems from by zinc pest removed M6 cameras.... Edited January 8, 2016 by duckrider Quote Link to post Share on other sites More sharing options...
Aoresteen Posted January 12, 2016 Share #15 Posted January 12, 2016 I took my M4-P to Iraq 2007-2008. It held up just fine. They are tough cameras - don't worry about it. Most often I was asked "How many megapixels does it have?" 1 Quote Link to post Share on other sites More sharing options...
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