brass and nickle silver

[jim currie]

a post in the wahl thread made me remember that i posted a researched ( as i couldn't find and hard facts in the controversy)thread in a brass rail versus nickle sliver in the old forum so here it is whit some updated info this is not to start a argument i hope just some facts. .

After this thread started I did a lot of research on the properties of both brass and nickel silver also known as German silver and come up with a ton of information so I tried to keep it as short as I could. But first the chemical composition of brass is copper and zinc the commonest alloy is 63% copper and 37% zinc nickel silver is copper zinc and nickel the common alloy is 65% copper 18% nickel and 17% zinc the conductivity of each base metal using silver as a rating of 100 copper comes in with a rating of 97.61 zinc at 29.57 nickel at 12.98 so it would stand to reason that nickel silver rail is not as good of a conductor as brass rail but we use such short runs of it that re stance is not factor.now as for the oxides the major component being copper in both brass and nickel silver the common black oxide we get on our track is called cupric oxide its conductive qualities I didn’t find a site that dealt with it(fore all the years of shuddering locos we all can guess on it), but did find that it is a toxic substance(new to me).nickel oxide is also black but being only 18% of the metal in the alloy that it will be found in smaller amounts (which is a good thing as it carries a cancer warning) as to the conductivity qualities if the base metal in of low conductivity of the oxide would stand to reason to be also lower. The zinc oxide is a whitish gray color is not toxic and harmless unless you ingest large amounts of it, but the fumes of zinc are deadly if breathed in confined spaces. The oxides from all three of these metals are used in the electronic industry from what I found mostly in the integrated circuit manufacturing. Also there I a myriad of other compounds that can be formed the such as sulfides which form in locations having sulfur compound fumes in the air .so from all I can find the only advantage to nickel silver track over brass is the appearance and that is why I only buy new track in nickel silver but use brass I have.

update information on this, the first solid state rectifiers were copper oxide, so the black copper oxide on our rails is a rectifier more or less

[nkp_174]

I have never had very good success with HO brass track. Nickel Silver on the other hand, has been great. I've found brass track to be difficult to keep clean...it sure seems to oxidize a heck of a lot faster. Everything I've ever read has confirmed this.

I believe the real issue is the rate of the reactions. I bet that if you look it up, you'll find that either the nickel inhibits corrosion or that it becomes a sacrificial anode for the copper which protects it. I've been up working for many hours...so I can't quite bring my knowledge of catalysis out of the memory banks to explain what role (if any) that it might have.

In my experience, brass is great for Large scale. Nickel Silver for HO and N. Corrosion seems to be more of an issue the smaller the scale (as is electrical pickup in general). As for adhesion, I can't recall how brass and nickel silver match up...but I do recall that steel is much better. The downside to steel is its poor conductivity. Hence there are the questions of whether a model locomotive should have nickel silver or steel tires.

[Beamish]

In general I think most people prefer nickle silver to brass. Just do a check on prices for buying brass compared to nickel silver. In most cases there are people who are just trying to get rid of the brass, to the point where some will just give it away.. I know I have a couple boxes of it that i don't plan to use. And it is not worth the shipping to sell it on ebay.

[bob_suruncle]

my understanding... (I read this somewhere but cant find the information) is that the oxidation on brass track is non-conductive where the oxidation on NS track is conductive?? (dont quote me... I read this somewhere else). In the end the proof is in the performance and remembering the hours of frustration I went through as a kid when all I had was brass track compared to the NS most of us use now.... I will never go back. NS also nicely represents shiny prototype railheads and more importantly if you want to have scale appearing track (anything smaller than code 100 with appropriate tie detail ...assuming you are not hand laying) you will have no success finding anything resembling "scale" track in brass... afaik its only available in code 100 sectional and flex and after a quick google I couldnt find anywhere that you can buy it new.

[Bob C]

Jim, Hi ! While it's true that copper is an excellent conductor, you are correct - it's oxide (cupric oxide) is very poor. While it may seem logical that less conductive nickle silver would have an even less conductive, that's not how chemistry works. I don't have the proof,(though will spend some time checking for evidence) the molecular configuration of nickle silver oxide may be nearly as conductive as the alloy itself. Chemistry is a BEAR, and does not follow standard logic in its operations. Hope I can at least find a citation. :ugeek: Bob C.

[Bob C]

Here's a whole bunch of relevent on Nickel -silver, only one reference mentions oxide conductivity (and not quantitatively), but
does state that the lesser conductivity is balanced for our use by it's SLOWer oxidation rate, and better than even copper soldering characteristics. Reference below, and link to more info including explaination of the health hazard at the end if the item:

NMRA RP-10 Trackage

Brass, Steel, and Nickel-Silver are the chief materials used for making rail. Brass is noted for its conductivity and good solderability, while Steel has half this conductivity and only fair solderability. Nickel-Silver has only half the conductivity of Steel but solders even better than Brass. Tractive effort on all three materials will be equal when the railheads are polished and clean, but oxide buildup on Brass and even more so on Steel increases the possible tractive effort on these materials. These same oxides, however, are generally non-conductive and require frequent use or cleaning to provide reliable current pickup. Nickel-Silver is nearly oxide-free and requires minimum maintenance while providing constant tractive effort of locomotives.

<!-- m --><a class="postlink" href="http://www.absoluteastronomy.com/topics/Nickel_silver">http://www.absoluteastronomy.com/topics/Nickel_silver</a><!-- m -->


Still looking for enlightenment !

[jim currie]

Jim, Hi ! While it's true that copper is an excellent conductor, you are correct - it's oxide (cupric oxide) is very poor. While it may seem logical that less conductive nickle silver would have an even less conductive, that's not how chemistry works. I don't have the proof,(though will spend some time checking for evidence) the molecular configuration of nickle silver oxide may be nearly as conductive as the alloy itself. Chemistry is a BEAR, and does not follow standard logic in its operations. Hope I can at least find a citation. :ugeek: Bob C.

all the information i found on both NiO greenish nickle oxide , Ni2O2 black nickle oxide , CuO black copper oxide and Cu20 dark red almost black copper oxide were all listed as semi conductors. some of the attributes often attributed to nickle silver( nickle brass as some metalergist call it ) are really the alloy silver nickle, silver 85% nickle 15% used in electrical contacts.
Jim

[Brakie]

Guys,What most modelers fail to realize is by painting brass track you stop the oxidization process..I know of 2 home layouts and 1 club that still uses brass track with zero problems.

Also just for fun..

Brass wheels on brass track gave your locomotives more tractive effort unlike nickel silver wheels on nickel silver track.

[Bob C]

Brakie, you are correct as far as appearance of the metal/oxide being covered by paint, but oxides effect the conductivity of the rail (and wheels) in the contact area (top and inner face of the ball or head). Here, the conductivity of the metal and its oxide, the rate of oxidation, and (to a lesser degree) appearance of the rail is important. As for TE, interfaces of like metals - steel/steel, brass/brass, nickel/nickel, are usually relatively sticky. Different metals slip more easily, a characteristic relied upon in making bearings/bushings for rotating machinery, yes ? It's not that brass doesn't do the job, only that (in some ways) nickel-silver is better IMO. Bob

[Puddlejumper]

As for TE, interfaces of like metals - steel/steel, brass/brass, nickel/nickel, are usually relatively sticky. Different metals slip more easily, a characteristic relied upon in making bearings/bushings for rotating machinery, yes ?

Also one of the most important characteristics of the steel wheel/steel rail interface used in prototype railroading...

[Brakie]

Brakie, you are correct as far as appearance of the metal/oxide being covered by paint, but oxides effect the conductivity of the rail (and wheels) in the contact area (top and inner face of the ball or head). Here, the conductivity of the metal and its oxide, the rate of oxidation, and (to a lesser degree) appearance of the rail is important. As for TE, interfaces of like metals - steel/steel, brass/brass, nickel/nickel, are usually relatively sticky. Different metals slip more easily, a characteristic relied upon in making bearings/bushings for rotating machinery, yes ? It's not that brass doesn't do the job, only that (in some ways) nickel-silver is better IMO. Bob

Bob,The advance modelers of the 50/60s would spray paint their track before laying it much like today's modelers does NS track...

Brass track gots its "evil" name from magazine "experts" and Linn Westcott back in the mid 60s...Of course this help push NS track making track advertisers happy...I used brass track as late as 1995 on one of my ISLs with zero problems and zero oxidization. This track was given to me as "junk"..I used for 3 years on that ISL.

[Bob C]

Larry, Thanks for the experience...I took 'em at their word at the time, bought code 70 NS rail and never did any empirical tests. I will take your word on the lack of effective difference. Bob C.

[nkp_174]

You can't paint the rail head...only the sides. I could care less about oxidation on the sides. Painting the sides will not affect corrosion on the top surface. Rather, regular running will polish the high iron...regardless as to what the high iron is made out of.

I don't think that you can make the claim that Linn Westcott killed brass...I never read his work until after I'd learned on my own that brass track was a waste of money. Why didn't RMC run a series of tests to prove that their rival's editor was wrong? I would expect the makers of brass track were not too happy about an editor shredding a product...regardless as to the accuracy of the statements.

[Brakie]

You can't paint the rail head...only the sides. I could care less about oxidation on the sides. Painting the sides will not affect corrosion on the top surface. Rather, regular running will polish the high iron...regardless as to what the high iron is made out of.

I don't think that you can make the claim that Linn Westcott killed brass...I never read his work until after I'd learned on my own that brass track was a waste of money. Why didn't RMC run a series of tests to prove that their rival's editor was wrong? I would expect the makers of brass track were not too happy about an editor shredding a product...regardless as to the accuracy of the statements.

Simple RMC had the same track advertisers that MR did.Its not good policy to unset the hand that feeds you.Never forgot RMC would follow MR lead..Ever wonder how the great G&D,V&O and other great layouts ended up in both magazines?

Linn Westcott was a very influential MR editor that remains unrivaled to this day...Even Hal Carsten never reach that plateau.

Cleaning the rail is a sure stopper on oxidation..

[jim currie]

You can't paint the rail head...only the sides. I could care less about oxidation on the sides. Painting the sides will not affect corrosion on the top surface. Rather, regular running will polish the high iron...regardless as to what the high iron is made out of.

I don't think that you can make the claim that Linn Westcott killed brass...I never read his work until after I'd learned on my own that brass track was a waste of money. Why didn't RMC run a series of tests to prove that their rival's editor was wrong? I would expect the makers of brass track were not too happy about an editor shredding a product...regardless as to the accuracy of the statements.

why do you say that brass track is a waste of money other than your opinion, as i have stated according to all the metalargy reports i have read brass and nickle brass ( nickle silver ) oxidise at almost the same rate and the common oxide to both is CuO, also all the reports state that the oxides of nickle are a semiconductor not a conductor . the proponents of nickle brass rail over brass rail not one has been able to back there clams with a lick of metallurgy evidents.