Author Topic: Oh what in 'Z' world am I doing?  (Read 2871 times)

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Re: Oh what in 'Z' world am I doing?
« Reply #45 on: February 08, 2024, 10:23:42 PM »
Most modern chassis are Zamak, which is mostly zinc with a little aluminum. Brass is copper with a bit of zinc. The base material ends up being twice the cost, and while it can be diecast, its less common. So finding someone who can and will would probably drive the cost up. Brass also corrodes more than zinc. Brass does machine very nicely, so for a smaller run it might be easier to machine it.

That  is all correct.  If you look at my post you quoted I specifically acknowledged that using brass would raise the model's price.

Tungsten is hard to machine. Its hard and abrasive and wears through tooling quickly. It also needs to be preheated before machining. No model train manufacturer is going to bother doing that. It's also expensive. Zinc is about a dollar a pound, copper three. Tungsten is $15 per pound for just the material.

I also agree with your statement.  And also in the post you quoted I did not mention machining it, but like Robert mentioned, use other means to form the weights or even the entire chassis.  Dapol did that for its N scale Terrier, so it is possible.

I wonder if that is more dense than 100% lead. Powders tungsten is not, but being pressed might make it win, but by how much?
Even if the tungsten weight or chassis formed from sintered tungsten were only as dense as Lead, that would still be a win since no model manufacturer will ever use lead again in newly produced models.  It would still be denser than Zamak or whatever white metal is currently used for model chassis. In small scale models every gram counts.
« Last Edit: February 08, 2024, 10:27:33 PM by peteski »
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Re: Oh what in 'Z' world am I doing?
« Reply #46 on: February 09, 2024, 01:58:05 AM »
Copper, even at $3 a pound, shouldn't raise the price of an N scale loco more than a dollar.  How many of our frames weigh more than 5 ounces?
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Re: Oh what in 'Z' world am I doing?
« Reply #47 on: February 09, 2024, 02:14:15 AM »
I wonder if that is more dense than 100% lead. Powders tungsten is not, but being pressed might make it win, but by how much?

I wondered this too, my quest to find the "ideal" metal for N and Z-scale engine chassis, pure Tungsten weight 19.3 grams per cubic centimeter, Lead weighs 10.65 grams per cubic PURE Tungsten is almost twice as heavy as Lead.

Sintered Tungsten powder alloy that's 90% W (Tungsten) mixed with Ni (Nickel) and Fe (Iron) reaches 17.01 grams per cubic centimeter at 1440 deg. C (2624 deg. F).  I have read of higher densities for sintered W alloy...up to 19 grams per cubic centimeter depending on the type of sintering process, such as "chemically activated sintering"...whatever that is!

So, to answer the question how much more sintered W alloy powder weighs than pure's a minimum of 1.67 times heavier and can be as much as 1.78 times heavier...which is significant.

On the other hand, if military grade Depleted Uranium (DU) were used to fabricate model engine chassis, it has several significant advantages over sintered W alloy powders, mainly consisting of it being much easier to machine and cast since it is classified as "easy to machine" and the melting temperature is 1,132 deg. C (2,070 deg. F).  Cast Iron's (which is very commonly cast) melting temperature is 1,204 deg. C (2,200 deg F)...only a few degrees higher than the melting point of DU.

From a machining standpoint, DU is commonly machined in industry by using common machining tools and methods with about the same difficulty as Stainless Steel.  Special care needs to be taken because of its pyrophoric effect...meaning that under high-speed machining operations (high temperature/high pressure), the chips can burn. 

Just exactly what is Depleted Uranium? Here's a quote:
"Depleted uranium is what is left over when most of the highly radioactive types (isotopes) of uranium are removed for use as nuclear fuel or nuclear weapons. The depleted uranium used in armor-piercing munitions and in enhanced armor protection for some Abrams tanks is also used in civilian industry, primarily for radiation shielding and aircraft balance control."

Just exactly what are the health hazards of DU? Here's a quote:
"Depleted uranium (DU) is a heavy metal that is also slightly radioactive. Heavy metals (uranium, lead, tungsten, etc.) have chemical toxicity properties that, in high doses, can cause adverse health effects. DU that remains outside the body can not harm you.

A common misconception is that radiation is DU's primary hazard. This is not the case under most battlefield exposure scenarios. DU is approximately 40% less radioactive than natural uranium. DU emits alpha and beta particles, and gamma rays. Alpha particles, the primary radiation type produced by DU, are blocked by skin, while beta particles are blocked by the boots and battle dress utility uniform (BDUs) typically worn by Service members. While gamma rays are a form of highly-penetrating energy, the amount of gamma radiation emitted by DU is very low. Thus, DU does not significantly add to the background radiation that we encounter every day.

I get nothing but a run-around when attempting to research how much military grade DU's spot market price is...but, it isn't cheap.  It has risen dramatically in the last year, along with the price of everything else, but, used in the quantities needed for N and Z-scale engine chassis, the actual increase in the price of an engine might be ten or twenty bucks...but that's just a guess.

Even though DU's low radioactivity won't significantly add to the normal background radiation we all live with, it carries a stigma with it that certain groups have given it, and continue to give anything that is associated with the Nuclear Industry or Military, which might be a deterrent to sales...and may make DU not worth using just because of the bad rap.

I thought this was interesting and worth sharing in this thread.

Bob Gilmore


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Re: Oh what in 'Z' world am I doing?
« Reply #48 on: February 09, 2024, 08:16:42 AM »
Pretty sure the Cotton Brute's chassis is made of DU, size of a U50 but will yank a several hundred car train up a %2 grade effortlessly. But yeah, with the sudden need lately for military grade armor piercing ammo its been in short supply.


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Re: Oh what in 'Z' world am I doing?
« Reply #49 on: February 09, 2024, 11:46:18 AM »
Depleted uranium is not going to have a market price, it is highly regulated. You are not going to be able to buy it legally.
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Re: Oh what in 'Z' world am I doing?
« Reply #50 on: February 09, 2024, 12:06:31 PM »
Depleted uranium is not going to have a market price, it is highly regulated. You are not going to be able to buy it legally.


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Re: Oh what in 'Z' world am I doing?
« Reply #51 on: February 09, 2024, 01:54:41 PM »
My Nn3 'test track' came about as I wanted to try an Nn3 version of my Climax A's from so many requests for a kit conversion.

So I started with some Rokuhan Z track which is basically Kato Unitrak in Z scale.   Maybe code 55?

Mark "Narrowminded" made some printed tie strip to use with Code 40 rail, seemed worth a shot to try it as it looked great.   I did several tracks with it, and initially, seemed to be wonderful.   His method for securing it was Pliobond on the rail base to hold it to the tie strip, heat to cure if necessary.   You had to pre-curve the rail.  It did hold gauge just fine and worked OK for well over a year.   It convinced me that Code 40 rail was feasible, worked with Rokuhan wheels, etc.   Mark had another wonderful solution, no rail joiners.  You put a feeder into every section and just butt-ended them together on the tie strip.   That actually worked.

Then I noticed little pieces of tie end showing up,  It was literally coming apart.   The Pliobond was reacting with the printed tie strip, and embrittling that material.   Mark said he'd changed material, but everything I had done for testing literally fell apart.   I tore all of it out and replaced it with Marklin Z sectional, including a couple switches.   I did discover that if you simply cut under the tie strip of Marklin you could change curve radius easily, and putting Caboose ground throws on the switches solved the electrical contact issues.   The Rokuhan and the Marklin combination didn't look as good as Marks but it's worked well at the train shows this module has appeared at.

I've had very few issues since.   I have 25:1 gearheads in my Nn3 Climax A's so the slow speed is somewhat absurd, but the Rokuhan shorty trucks stay fairly clean and I have no stalling issues at all.  I think one of my advantages is I'm using one of the Z 'Blue Snail' throttles running on a 9V battery, just outstanding speed control.   Those are a wonderful little throttle for Z and can even tame the rocket-like Rokuhan SA chassis without the gearhead.   Rokuhan has made Z (Nn3) possible for me for a practical dual-gauge Ttrack module and it's rather inexpensive.  Prior to that the thought of hacking up Z stuff for an expiriment was rather intimidating.

I got crazy enough to build some dual gauge track and a dual gauge turnout out of Rokuhan stuff cut and glued back together, that worked too.

I was similarly astounded that everything works with the Rokuhan 4 1/2" radius curves although my cars are shorty Showcase Miniatures flatcars and log cars and one converted Bachmann old time boxcar to Nn3.    I've painstakingly hand-painted all the Rokuhan with weathered ties on dirt-brown ballast section (this is a logging railroad) and would recommend that on a smaller module like I'm doing.

I've also done several custom builds of my Whitcomb centercab over an Aztec Z GP chassis to make a narrow-gauge Whitcomb centercab.  Hey, those existed too.   I was really impressed with the quality of that mechanism and performance.    Overall, I'm much less of a skeptic on Z than I am on DCC!

« Last Edit: February 09, 2024, 02:18:12 PM by randgust »