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Post by bn7023 on Nov 1, 2022 16:20:05 GMT -8
Older Japanese and US modelers experienced zinc rot on O-gauge in the 1940s and 1950s. Manufacturers reflected on this and implemented thorough quality control. Since 2000, many tragedies happened again when people who didn't know it ordered models from manufacturers in emerging countries. Railroad and auto models suffer less damage. A lot of tragic disasters happened in model aircraft. Do a search and you will see harrowing images that make you want to turn your eyes away.
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Post by edwardsutorik on Nov 1, 2022 17:07:54 GMT -8
I have a number of Ulrich HO kits made in the late '50's, I believe. Several have zinc pest. So it did get into HO back then. And I'm pretty sure they were cast here in the USA.
There's a fair chance I tossed the bad ones out when I discovered it--what good are they? But there were some that were OK, and I (sort of) look forward to seeing how they're doing.
As I'm fond of saying: "They're in a box somewhere in the garage."
Ed
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Post by atsf_4 on Nov 1, 2022 18:22:56 GMT -8
Another hobby is diecast musclecars. I've had a difficult time finding good, accurate, and well assembled models of certain muscle cars (they too are made in SE Asia). I recently learned that even models made within the past 20 years are having issues. They refer online to some kind of "paint bloom" where the paint on the diecast car fails over time and starts to bubble and is apparently fairly common even with the "best" makes. What I'm really wondering is if in fact that bubbling paint is actually zinc pest beginning to rear its head...just like I vividly remember how good the Oriental Limited Powerhouse series diecast zamac articulateds looked when they were new, and I've seen plenty of images online showing the paint failing, and I cannot help but wonder if in fact that is actually zinc pest occurring. Those steam engine boilers would be about 36 years old now...right time frame. Keeping the metal painted only slows it down. They were made by Samhongsa, allegedly by that time one of the "best" builders...though Japanese brass fans will dispute that.
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Post by selector on Nov 2, 2022 13:08:30 GMT -8
This problem, such as it is, is very much a responsibility of the purchaser who should also set strict specs AND to QA of the product. Except, it's hard to determine that a component will fail before 10-15 years have passed when it typically shows up. Unless, and I will stand to learn something from a knowledgeable person, electrical/sampling/spectroscopy/imaging technologies allow reasonable assurances that a component is not meeting specs.
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Post by edwardsutorik on Nov 2, 2022 14:47:31 GMT -8
This problem, such as it is, is very much a responsibility of the purchaser who should also set strict specs AND to QA of the product. Except, it's hard to determine that a component will fail before 10-15 years have passed when it typically shows up. When you say "purchaser", I am assuming you mean the person/company that purchases the casting alloy in bulk. Ed
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Post by bn7023 on Nov 18, 2022 1:01:04 GMT -8
The Japanese Industrial Standards standard-sheets were published on the Internet. The composition of the ingot can be determined. Translating Japanese into English is easy. JIS H2201-2015 Zinc alloy ingots for die casting JIS H5301-2009 Zinc Alloys Die Castings Couldn't find ISO or ANSI. By the way, the Powerhouse series models were owned by a friend. They were manufactured in 1987-1990(?), low-priced HO scale steam locomotive models that Oriental Limited had Samhongsa build. The series had a hybrid configuration that combined brass with a die-cast boiler, etc., and I think it was an epoch-making product at the time. USRA's 2-8-8-2, 2-8-2 light, 4-6-2 light, and logging 2-4-4-2 were available. He liked the series, even though it had some weak points in the valve gears and tender trucks. The reason was the very existence of these weaknesses, which he gladly fixed. Come to think of it, Samhongsa and Ajin used zinc die-cast gear cases.
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ed
Full Member
Posts: 129
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Post by ed on Nov 18, 2022 7:20:43 GMT -8
I had an Ertl 1/18 Camaro that shattered like a dropped glass Christmas ornament. Never had taken it out of the box. Happened all by itself without dropping it. Ominous....
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Post by atsf_4 on Nov 18, 2022 7:28:25 GMT -8
bn7023--
I only referred to Powerhouse Series engines up above because I'm seeing photos of some in online auctions where it appears there might be zinc pest starting to show through the paint. Again--paint retards the corrosion process by limiting exposure to oxygen but will not stop it.
I owned 2 of the 2-8-8-2's when they were brand new. The paint was typical Samhongsa excellent at that time.
Also one common issue with the full brass models is that many of the gearboxes used in the 1960's and some even into the 1970's suffer from inter-grannular corrosion (zinc pest) today to the point that they will crumble to dust and must be replaced.
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Post by fishbelly on Nov 18, 2022 11:58:23 GMT -8
Lots of the Concor (ex Roco) GP38/ GP40 frames that were made in Mexico are prime for crumbling. So far three of the Made in Mexico frames I have or had just fell apart like they were made from sand. It was truly amazing to witness. I pulled the shells off and removed the trucks and the frames just disintegrated into piles of tiny pizza sausage.
The made in Austria frames are pretty solid and stay together nicely. Like they should.
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