rob D2 Posted November 16, 2020 Author Share Posted November 16, 2020 My email has been forwarded to R&D for comparison with the samples. I pointed out people’s issues with 37242 and 254 from the same era, and also sent additional close ups showing the reptilian style scales to the chassis. will revert . 1 2 Link to post Share on other sites More sharing options...
Tony Walker Posted November 16, 2020 Share Posted November 16, 2020 Had a look at the five I have and there's definitely a problem with 37174 and 327254. 254 is banana shaped, but 174 isn't too bad at the moment, but there's something wrong. I've taken both bodies off, but need to have a closer look this weekend. I've had a look at 37242, 37405 and 37421 and they all look OK, but I haven't taken the bodies off, as they appear outwardly to be OK, which wasn't the case with the other two. It will be interesting to see what comes back from Bachmann on this. Hope I don't have to send them away to get fixed, as I've modified 37254 by putting a large speaker in the fuel tank! Don't think that would cause the banana effect though. 1 Link to post Share on other sites More sharing options...
rob D2 Posted November 16, 2020 Author Share Posted November 16, 2020 29 minutes ago, Tony Walker said: Had a look at the five I have and there's definitely a problem with 37174 and 327254. 254 is banana shaped, but 174 isn't too bad at the moment, but there's something wrong. I've taken both bodies off, but need to have a closer look this weekend. I've had a look at 37242, 37405 and 37421 and they all look OK, but I haven't taken the bodies off, as they appear outwardly to be OK, which wasn't the case with the other two. It will be interesting to see what comes back from Bachmann on this. Hope I don't have to send them away to get fixed, as I've modified 37254 by putting a large speaker in the fuel tank! Don't think that would cause the banana effect though. If it mazak, the Only thing that will fix it is a new block combined with the old plastic sub chassis, or if that is too bent , a whole new chassis 1 Link to post Share on other sites More sharing options...
Chris Rowe 37419 Posted November 16, 2020 Share Posted November 16, 2020 (edited) I think this has the same issue. I am not sure what it has been resprayed from but the chassis does not sit right. Edited November 16, 2020 by Chris Rowe 37419 Adding photos Link to post Share on other sites More sharing options...
rob D2 Posted November 16, 2020 Author Share Posted November 16, 2020 That’s looking very similar to mine , even down to what I am assuming is factory weathering ? Link to post Share on other sites More sharing options...
Tony Walker Posted November 17, 2020 Share Posted November 17, 2020 11 hours ago, rob D2 said: That’s looking very similar to mine , even down to what I am assuming is factory weathering ? Snap! Link to post Share on other sites More sharing options...
'CHARD Posted November 17, 2020 Share Posted November 17, 2020 14 minutes ago, Tony Walker said: Snap! Hope not! 2 Link to post Share on other sites More sharing options...
RMweb Gold pheaton Posted November 17, 2020 RMweb Gold Share Posted November 17, 2020 Tell tale cracking under the drivers desk shows that is indeed Mazak rot. Link to post Share on other sites More sharing options...
georgeds Posted November 17, 2020 Share Posted November 17, 2020 These kind of things are starting to make me think twice about buying any more models, and even consider selling up what I have. Been collecting over the years in preparation for having a location to build a layout "one day", and the idea that my collection will be full of expanded chassis and knackered bodies is worrying. Link to post Share on other sites More sharing options...
RMweb Gold pheaton Posted November 17, 2020 RMweb Gold Share Posted November 17, 2020 (edited) to be fair its a minority of models affected so far, it would have been obvious by now given the age of some of the 37s if it was a more widespread problem. Ive got about 47 Bachmann class 37s of all ages and ive been lucky to not have suffered with any to date, but the body of the class 37 is (obviously not intentionally) designed that the nose will come off before any damage occurs. Ive lost several Hornby class 31s to this issue, but managed to rescue the bodies. Thankfully though the Bachmann class 37 is easier to rebuild as its much less complicated internally than the 31, but as long as Mazak is in use for the chassis this problem is always a potential issue. Hopefully Bachmann will make spare chassis available. Edited November 17, 2020 by pheaton 1 Link to post Share on other sites More sharing options...
Pacific231G Posted November 17, 2020 Share Posted November 17, 2020 Are all Mazak components eventually subject to this but at different rates or is is purely A QC problem? I have a number of 20-30 year old models and wonder if they have a definite shelf life. Link to post Share on other sites More sharing options...
RMweb Gold pheaton Posted November 17, 2020 RMweb Gold Share Posted November 17, 2020 (edited) Its a QC problem, basically the Mazak has been improperly prepared and a contaminant (lead) has been introduced or a poor quality zinc has been used. Mazak (when properly prepared) is an extremely stable alloy. Edited November 17, 2020 by pheaton 3 1 Link to post Share on other sites More sharing options...
RMweb Gold Joseph_Pestell Posted November 17, 2020 RMweb Gold Share Posted November 17, 2020 (edited) 7 minutes ago, pheaton said: Its a QC problem, basically the Mazak has been improperly prepared and a contaminant (lead) has been introduced or a poor quality zinc has been used. Mazak (when properly prepared) is an extremely stable alloy. There were quite a few problems with deficient Mazak in the 1960s. Pocher car kits were renowned for it despite being very expensive and collectable. Since then, the problem seems to have disappeared until production was outsourced to China. This is a basic manufacturing fault and, as such, under consumer law, comes outside the manufacturers' guarantee terms and conditions. These faulty products should be replaced free of charge. Edited November 17, 2020 by Joseph_Pestell 1 1 Link to post Share on other sites More sharing options...
RMweb Gold Joseph_Pestell Posted November 17, 2020 RMweb Gold Share Posted November 17, 2020 16 minutes ago, Pacific231G said: Are all Mazak components eventually subject to this but at different rates or is is purely A QC problem? I have a number of 20-30 year old models and wonder if they have a definite shelf life. No, if the Mazak has been made properly, it will last for ever. I have models that are sixty years old and still absolutely fine. 1 1 Link to post Share on other sites More sharing options...
RMweb Gold pheaton Posted November 17, 2020 RMweb Gold Share Posted November 17, 2020 (edited) Its been a known issue since the 1920s @Joseph_Pestell TBF to china, its likely down to impure zinc alloy, which its unlikely random testing of the ingots would spot. Interestingly @Chris Rowe 37419s loco shows two issues, one is the dreaded zinc pest, the other weisrost or wet storage staining, as seen on the second picture to the left of the cab door, which is a non serious issue. I had it appear on some Bachmann 47s and reported it a while ago, but its not linked to zinc pest. To eliminate the problem entirely you would have to test each ingot before the melting process, which isn't practical in high volume manufacturing and would push the costs up of the product exponentially. Edited November 17, 2020 by pheaton 1 1 Link to post Share on other sites More sharing options...
RMweb Gold Joseph_Pestell Posted November 17, 2020 RMweb Gold Share Posted November 17, 2020 3 minutes ago, pheaton said: TBF to china, its likely down to impure zinc alloy, which its unlikely random testing of the ingots would spot. So where is the impure alloy coming from if not China? Link to post Share on other sites More sharing options...
RMweb Gold pheaton Posted November 17, 2020 RMweb Gold Share Posted November 17, 2020 There are at least 7 world wide exporters of zinc alloy for the asian manufacturing markets and they all have different quality standards. Link to post Share on other sites More sharing options...
rob D2 Posted November 17, 2020 Author Share Posted November 17, 2020 I’ve never had a problem with Bachmann before . All the predicted Hornby 31s I had fell apart but Hornby customer service was up to replacements . 1 Link to post Share on other sites More sharing options...
'CHARD Posted November 17, 2020 Share Posted November 17, 2020 1 hour ago, pheaton said: Ive got about 47 Bachmann class 37s of all ages 'About' 47! 2 Link to post Share on other sites More sharing options...
atom3624 Posted November 17, 2020 Share Posted November 17, 2020 .... and when you can locate them all, how are they? Is this related to how they've been stored? I have 2x Bachmann 37's, both brilliant runners and look great, pending the 3rd from 'another manufacturer based in Ireland'. Both of mine are fine - kept in a dry garage - only place I have for storage. Al. Link to post Share on other sites More sharing options...
Pacific231G Posted November 17, 2020 Share Posted November 17, 2020 (edited) I hadn't realised that Zamak iwas actually developed (by the New Jersey Zinc Company in 1929 as the solution to the problem of Zinc Pest not the cause of the problem. Mazak appears to have been a British trade name for a local version licenced from NJZ but based on an electrolytic refinement of the less pure zinc available here. So far I've only knowingly encountered Zinc pest in things like old wagon wheelsets that are fairly easily replaced (which with pizza cutter flanges they need to be anyway) The other problem I've found with older models are injection moulded plastics that become brittle with time but that's . Materials Science wasn't my strongest subject when I studied engineering but there appear to be five different types of Zamak in common use (2,3,4,5 & 7) with three (96% zinc, 4% aluminum) the defacto standard and the most common type used in N.America. Zamak 5 with 1% copper is commonly used in European and Zamak 4, with 0.5% copper used in Asia. I don't know whether the type of Zamak used is relevant to this problem or whether that is purely a QC problem. Edited November 17, 2020 by Pacific231G Link to post Share on other sites More sharing options...
RMweb Premium spamcan61 Posted November 17, 2020 RMweb Premium Share Posted November 17, 2020 Looks like these 37s need adding to the existing zinc pest list:- https://www.rmweb.co.uk/community/index.php?/topic/123769-zinc-pest-mazak-rot-the-affected-models-list/&tab=comments#comment-2757031 Link to post Share on other sites More sharing options...
RMweb Gold Phil Bullock Posted November 17, 2020 RMweb Gold Share Posted November 17, 2020 Oh no..... have some locos based on these better get them out and check..... Link to post Share on other sites More sharing options...
'CHARD Posted November 17, 2020 Share Posted November 17, 2020 1 hour ago, spamcan61 said: Looks like these 37s need adding to the existing zinc pest list:- 56 minutes ago, Phil Bullock said: Oh no..... have some locos based on these better get them out and check..... Do we know which serial numbers are involved, usually there are several locos produced in parallel in the factory. 37174 is 32-786 37254 has been released a couple of times in different liveries, are we talking about 32-785 in Departmental livery which is the adjacent serial No.? Link to post Share on other sites More sharing options...
37114 Posted November 17, 2020 Share Posted November 17, 2020 20 hours ago, rob D2 said: If it mazak, the Only thing that will fix it is a new block combined with the old plastic sub chassis, or if that is too bent , a whole new chassis It might be worth removing the block from the chassis to prevent further damage. Link to post Share on other sites More sharing options...
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