Zinc Pest and Plastic-bodied Steamers

No thank you, I do not want Plastic body steamers!

I posted about a year ago about using plastic instead of diecast and it was overwhelming in that nobody agreed it was not wanted. So diecast it is. 

Dave

Ask again when our Legacy BTO steamers start exhibiting these characteristics. I still like diecast until then!

No plastic steamers, period. And get over this zinc rot fear. I haven’t had one diecast steamer in O gauge, N scale and HO scale succumb to zinc rot, and I have plenty, ranging in age from recent to 70 years.

Oh, and I have had a half dozen plastic diesels damaged and generally crack from moderate falls. Plastic guarantees nothing in terms of longevity over diecast. 

Plastic is lots cheaper, and takes crisper detail.

You won't find many plastic models of anything here.  Toy-like, to me.

To avoid a shark attack, stay out of the water.  (That is in the survivor's guide to the TV show SURVIVOR.)

To avoid zinc rot, stay away from zinc!

Thete should be some other metals one could use to make trains!

FYI, Brass/Bronze models don't get zinc pest!     Myabe that is why the old time model RRs liked them so much.

Were any postwar or MPC/LTI engines affected by this?

aussteve posted:

Were any postwar or MPC/LTI engines affected by this?

There were a number of 700-E Hudsons that suffered from Zinc rot, although technically that's prewar.

Don't recall offhand of any MPC/LTI die cast engines suffering from it, but I've seen first hand a couple of early MPC-era die-cast sprung trucks fall apart from it.

Gimme plastic anytime.  If AHM could do a great job of it 50 years ago, I'm sure someone could do it better now.

Jim R. posted:

No plastic steamers, period. And get over this zinc rot fear. I haven’t had one diecast steamer in O gauge, N scale and HO scale succumb to zinc rot, and I have plenty, ranging in age from recent to 70 years.

Oh, and I have had a half dozen plastic diesels damaged and generally crack from moderate falls. Plastic guarantees nothing in terms of longevity over diecast. 

Unless it is the Lionel GG-1 trucks it seems.

I would definitely prefer plastic as it is much easier to repair if necessary. Although I do like the early bronze/brass models like those by E. P. Alexander, Baldwin Model Locomotive Works, and others. They shure do have some weight for traction! This one weighs in at thirteen-plus pounds or so:

Jim R. posted:

No plastic steamers, period. And get over this zinc rot fear. I haven’t had one diecast steamer in O gauge, N scale and HO scale succumb to zinc rot, and I have plenty, ranging in age from recent to 70 years.

Oh, and I have had a half dozen plastic diesels damaged and generally crack from moderate falls. Plastic guarantees nothing in terms of longevity over diecast. 

I used to pick up prewar Flyer 3/16s O gauge diecast steamers and had examples of the Pennsy K-5, B&O Royal Blue, NYC Hudson, UP Northern, Reading Atlantic and NKP 0-8-0 boiler shells crumble from just backing out screws, diecast tender frames, sideframes and shells bow, diecast freight car bodies that warped - zinc pest is very real. I don’t think there exists a prewar Flyer NKP switcher that is completely original that’s capable of running. I’ve also had some modern diecast truck sideframes disintegrate in the last 10 years. My brothers had a Rivarossi early 60s era HO 2-8-0 that had a diecast tender frame rot, and I have owned or currently have N scale Rivarossi steam engines in my junk box whose chassis have crumbled - I guess I’ve made up for your fortunate streak of not having the misfortune of experiencing zinc pest at work.

NYC 428 posted:

No thank you, I do not want Plastic body steamers!

But some will pay a squillion dollars for a plastic diesel. No logic there.

bob2 posted:

Plastic is lots cheaper, and takes crisper detail.

You won't find many plastic models of anything here.  Toy-like, to me.

Plastic models are often not much cheaper to make; the design, engineering, production and marketing are the major costs, not the materials.  And, have you ever looked at those HO/N "toy-like" plastic/mostly plastic/plastic hybrid steamers?

Now, about plastic upscale rolling stock....last time I checked they didn't look "toy-like".

Jim R. posted:

No plastic steamers, period. And get over this zinc rot fear. I haven’t had one diecast steamer in O gauge, N scale and HO scale succumb to zinc rot, and I have plenty, ranging in age from recent to 70 years.

Oh, and I have had a half dozen plastic diesels damaged and generally crack from moderate falls. Plastic guarantees nothing in terms of longevity over diecast. 

Generally my experience, too.

prrjim posted:

FYI, Brass/Bronze models don't get zinc pest!     Myabe that is why the old time model RRs liked them so much.

Cast brass and bronze were older technologies and often not pressure die-cast. The zinc process is higher-tech. Formed brass - sheet - is a whole 'nuther planet. 

=======

As a steam scratch-basher, I have so often cussed that zinc - and brass, too - when modifying a steamer. Plastic would have made the job much more enjoyable. And if you think plastic is delicate, my plastic MTH 1:32 J3a Hudson would like to disagree.   

Plastic was introduced to the hobby because it was substantially cheaper due to lower tooling costs and materials. But that was another time.

The dies produced for today’s zinc alloy castings aren’t made to last decades any longer, a nod to the size of the hobby market and realized savings. So the tooling issue is roughly the same as plastic for steamers.

A steam locomotive produced from plastic would carry a cost difference of maybe 10 or 15 percent.

As for the market, if plastic is so superior, why then have Bachmann, Broadway Limited, MTH and others (including Model Power, whose line continues under new ownership) produced diecast steamers in lieu of plastic ones in the past 20 years in N and HO scale? Answer: Better weight, increased durability and perceived value.

For O gauge, the die has been cast. Metal steamers are preferred by the huge majority, so accept it and move on with your lives.

Oh, and no one is suggesting that zinc rot doesn’t exist, and Chinese production, which for our hobby relies too heavily on small-time subcontractors who don’t follow production standards that became well established after World War II, can be problematic. But the problem is easily correctable, and the vast majority (like more than 95 percent) of our models produced in China exhibit no zinc rot problems whatsoever.

One plastic advantage:  You could have a basic running gear.  Say a 4-6-2.  then you could make a run of a regular K4s.  Then a streamlined one.  Then a TNO SUNBEAM streamlined steamer......

Maybe not for the scale line, but entry level sets.  Modular construction.....

Diesel locomotives have plastic bodies......

Thete is no one good universal answer for this.

.

Jim R. posted:

 

For O gauge, the die has been cast.

No pun intended, I'm assuming. 

LGB used a superior high-tech BASF polymer called Luran S, (NOT your typical plastic) for their original engines and rolling stock. Another high-tech polymer, Vestilene, was used for their track ties. It was even impervious to acetone! Both of these high grade plastics were very durable and could withstand extreme ranges of temperature and UV rays.

NOT all plastics are created equal.

I think plastic-bodied steam locos is a solution to a problem we are not having. Has anyone actually had a recent steam engine where the loco body failed because of zinc pest? I know there were some that had trouble in the early 2000s, but since? None that I recall, though I would be happy to be corrected.

What seems to fail are trucks and detail parts. Plastic detail parts...once they're painted, who's going to notice? Plastic trucks might be a harder sell, though. Styrene isn't durable against wear and delrin doesn't take paint too well.

I like the "heft" of a die-cast metal steamer.

Lionelski posted:

I like the "heft" of a die-cast metal steamer.

 

Absolutely. 

Plastic with brass appliances for me would be the winning combination.  Bells, whistles, domes, side rods and gear, boiler, cab, and tender shells could all be plastic, NOT chassis.

If Lionel or MTH offered one right now all you naysayers would be jumping thru hoops getting your orders in and you know it

ELIMINATE ZINC PEST NOW!!!  (should be our motto )

The "heft" can be duplicated with proper placement of weights. Delrin and styrene are inferior to Luran S.

It's not just the body.  Think about it... what would the chassis be made of?  The wheels, too.  A postwar Lionel 1130 is a plastic-bodied steam loco.  Some of these had ballast weights added and could almost equal the die-cast 2034 in pulling power.  But the wheels were cast, some kind of powdered metal, and occasionally subject to deterioration.  The Marx 1829 Hudson had similar construction.  Both of these postwar locos used a "parallel plate" chassis made out of stamped steel plates separated by die-cast spacers.  When K-Line reissued the Marx Hudson, it still had a plastic body.  But they used the new worm-drive chassis developed for the updated 333.  Guess what?  The chassis was die-cast metal.  So were the gears and driving wheels.

The real solution is better quality control.  The "manufacturers" (now largely importers) have to do more to protect their reputation.  The fact that there are so many different models now takes away the safety net that was afforded by long production runs and interchangeable parts.  There's a real risk that your $1500 loco will become inoperable.  And if all of the pieces in a batch are affected, even cannibalizing parts from another unit won't be an option.

Brass is generally thought of as pure and not subject to intragranular disintegration.  So cast bronze or brass would be my choice.  I'm NOT talking about sheet brass that's soldered together by hand.  I've seen too many of those falling apart at 2-rail scale meets!  Also, brass corrodes in the presence of chlorine vapors (something to think about if your layout is near a washing machine or a shelf of cleaning supplies) Heck, I'll probably turn to dust myself in about 50 years.  Even Superman is vulnerable to Kryptonite!

Bob Delbridge posted:

Plastic with brass appliances for me would be the winning combination.  Bells, whistles, domes, side rods and gear, boiler, cab, and tender shells could all be plastic, NOT chassis.

If Lionel or MTH offered one right now all you naysayers would be jumping thru hoops getting your orders in and you know it

ELIMINATE ZINC PEST NOW!!!  (should be our motto )

Really? Except for the same small group expounding on why they want plastic, I see the group overwhelmingly in favor of diecast steamers. You’re in the very small minority. And manufacturers know it. Which is why zinc alloy castings for bodies will continue.

How about cast aluminum as a substitute for zinc alloy castings?

I lust for a good die cast PA or E7.  Not gonna happen - only steam and electrics must be die cast.  Who makes these rules?

Diecast does not seem to hold detail as well as Plastic.    Compare the Atlas fishbelly hopper with the MTH fishbelly hopper.   these are both models of the same car.    The body on the MTH is plastic and the detail in my opinion is much sharper.

As for steamers or diesels, I prefer brass - not cast bronze as first choice because especially for steamers which are hard to find a place to pick that is not fragile.    Diesels on the other hand more more surfaces y ou can pick up so plastic bodies are just fine.   

I think frames and running gear should be brass, bronze or steel.    Cast aluminum might work too.   Any fine mechanical parts such as rods which on scale engines usually transfer power, should be steel.    Detail parts can be lost was brass castings which have shown for  years they are really detailed.   

Diecast steam superstructures have two disadvantages in my opinion.    First there is often cast on detail which tends to be crude compared to separate lost was parts.    Second, the thickness of anything with visible edges looks way too thick and crude.   Cab windows, the edges of cab roofs, tender coal boards etc. just don't look right to me.    

Cast aluminum is about half the density of Zamac.  (There's a reason they don't make airplanes out of die-cast metal .)  So anything made out of cast aluminum would feel light by comparison.  Just like plastic, you would probably have to add ballast weight.

Ted S posted:

It's not just the body.  Think about it... what would the chassis be made of?  The wheels, too...

... The real solution is better quality control.  The "manufacturers" (now largely importers) have to do more to protect their reputation.  The fact that there are so many different models now takes away the safety net that was afforded by long production runs and interchangeable parts.  There's a real risk that your $1500 loco will become inoperable.  And if all of the pieces in a batch are affected, even cannibalizing parts from another unit won't be an option.

Absolutely...

Mark in Oregon 

AL in a hot humid place like Houston may not work.  AL tends to pit if the surface is not coated right.

Count me in the minority of ones who would like a plastic steam loco and all of the great possibilities that a kit could provide!

And TED S, the running gear would have to be metal.

DOMINIC: Aluminum can receive an anodized coating that can protect it from such humid conditions. I believe such a finish will also allow paint to adhere to it.