View Full Version : Conductivity: Gold vs.Silver?


citylights17@ho
10-11-2007, 10:28 PM
Does anyone have an opinion on using gold plated or silver plated electrics in G3 or any other HO slot cars? Does it matter more on some parts than others? Does it matter at all? I use gold....... well because some think it is better. But i don't know. I'd like your sage advice. thanks, mj

Crimnick
10-12-2007, 09:53 AM
Gold is the better conductor.

lordraptor1
10-12-2007, 05:06 PM
sorry but silver is better, gold is only better for corrosion resistance. silver is actually the better conductor from all i have read, besides underneath all of that gold plating is silver and wires ar not gold through either so if gold was the better condutcor (which it is not) you would lose the benefit in the wires anyway. just my .02

noddaz
10-12-2007, 05:22 PM
I can whip out the chart I stole from the web.... :lol:

* At 20º Celsius, based on copper as 100.
** Per degree C at 20º C.
Note: The conductivity of various metals is subject to variation according to processing and alloy composition.


Aluminum 59
Brass 28
Cadmium 19
Chromium 55
Cobalt 16.3
Constantin 3.24
Copper:
Hard drawn 89.5
Annealed 100
Gold 65
Iron:
Pure 17.7
Cast 2-12
Wrought 11.4
Lead 7
Manganin 3.7
Mercury 1.66
Molybdenum 33.2
Nichrome 1.45
Nickel 12-16
Nickel silver 5.3(18%)
Phosphor bronze 36
Platinum 15
Silver 106
Steel 3-15
Tin 13
Titanium 5
Tungsten 28.9
Zinc 28.2

Look how far down the food chain that nickle is...
(Just an observation...)

Scott

citylights17@ho
10-12-2007, 09:45 PM
Please clarify for me. Is your chart saying that copper is better than gold??
mj

Hornet
10-13-2007, 12:33 AM
Save your money and buy the cheap stuff,silver tarnishes very rapidly and builds surface resistance,and clean copper is as good a conductor as gold.

AfxToo
10-13-2007, 06:29 AM
Is your chart saying that copper is better than gold??

Yes, silver, copper, and then gold for bulk conductivity. As others have said gold has excellent corrosion resistance which is why it's so popular for high reliability contact/mating applications like card edge connectors and electronic connectors. For pickup shoes, well, it looks pretty but is probably of little to no added value on the track.

I think the JL/AW and LL cars and others use a zinc plated copper for their pickup shoes. That's a fairly common combination for electrical contacts where you want higher durability, especially where arcing is involved. The AW cars would be slightly better electrically if the chassis electricals were copper.

citylights17@ho
10-13-2007, 10:28 AM
I tend to use gold on my endbell and pickup holders and copper shoes. mj

mtyoder
10-13-2007, 01:55 PM
Didn't realize aluminum was that conductive compared to the other stuff. Is there a way to solder aluminum? Tried before, no luck.

Bill Hall
10-13-2007, 04:01 PM
Ditto. Never seen solder stuck to anything Al in my life...nice to dream though

Al requires it's own flux. Seen old school dudes do it with oxy/acet. Tried it. Not easy! Been burning since high school and have run most rigs to some extent.

Al. is highly conductive! Problem is the fatigue factor and the minimum fusion temp is high.

For the most part unless yer TIG'en er MIG'en, the only thing you'll get to stick to Al. is dirt, yer own scorched flesh, and occasionally some Cecil Muggy alloy stick

The only stuff I've ever seen is the old door to door salesman Cecil Muggy sticks and their ilk.

Dunno whatcher building, but it's gotta be tiny compared to the generally accepted application.

I'll see if one of my buds has some Yoder, It's usually hangin around in some dusty corner of the shop cuz it was tossed aside in frustration...ya see it requires skill to master. Gimmee a few days and if ya dont hear back...kick me in the can!

If ya can braze, ya may be able to finger out a way do do it with a crack lighter.

A brazing process more or less. Supposedly requires their special flux too if I remember correctly.

The stuff is pretty globular for rookies...lol ...but with some practice I got a few things to come out rather nicely.

joez870
10-13-2007, 04:03 PM
Aluminum may be tig-welded, not soldered, eh.
When welding you are melting both surfaces to be joined and adding material inbetween.

Dranoel Dragon
10-13-2007, 07:50 PM
Ok, I'm sorry but there are some people who are wrong here. Gold is the only metal in the world that is a superconducter at ANY temperature. Silver and copper can become superconductors, but only when frozen to rediculous temperature like -450*F. Why do you think computer chips are made with gold circuitry on the wafers instead of coper or silver?

Another tidbit to bake with your noodles: Electricity does not flow through metal. It flows around it. Across the surface of it. I get a kick out of people advertising "Solid-rivet" chassis as if they are the greatest thing Aurora invented. The sad fact is the hollow rivet chassis flows electricity better because of the larger surface area of the hollow rivet. Granted, it's not a huge difference and wouldn't be either way. But some people just don't understand the laws of electricity.

joez870
10-13-2007, 07:58 PM
Ok, I'm sorry but there are some people who are wrong here. Gold is the only metal in the world that is a superconducter at ANY temperature. Silver and copper can become superconductors, but only when frozen to rediculous temperature like -450*F. Why do you think computer chips are made with gold circuitry on the wafers instead of coper or silver?

Another tidbit to bake with your noodles: Electricity does not flow through metal. It flows around it. Across the surface of it. I get a kick out of people advertising "Solid-rivet" chassis as if they are the greatest thing Aurora invented. The sad fact is the hollow rivet chassis flows electricity better because of the larger surface area of the hollow rivet. Granted, it's not a huge difference and wouldn't be either way. But some people just don't understand the laws of electricity.

Electricity is flowing across the surface of my brain, but after reading this, it now hurts INSIDE my brain. ;)

DD, you are just too smart to be playing with lil toy cars! :D

Bill Hall
10-13-2007, 08:48 PM
Hmmmm.
Didnt know that solid rivet chassis were purported to be better elcectrically.

Thought is was more about the wiggling hangerplate syndrome and better materials used in their construction.

Anybody...?

vaBcHRog
10-13-2007, 09:39 PM
Hmmmm.
Didnt know that solid rivet chassis were purported to be better elcectrically.

Thought is was more about the wiggling hangerplate syndrome and better materials used in their construction.

Anybody...?

Nah! The reason solid rivet chassis got the great rap is the were the first ones made aqnd are much older and better broken more track time, so 9 out of 10 solid rivet chassis you get off ebay end up be very nice running TJETS.

Just my theory. Same us eto be true when I ran HOPRA 440X2 Super Stocks. ( out of every 10 cars you got at a yard sale ran very well as they were well broke in and due to the small size of most home tracks never really got dogged out.

Roger Corrie

RacerDave
10-13-2007, 10:02 PM
Good news. I'm safe with silver electricals because I like to run my cars at around 450 below. Brrrrrrrrrrr. Is it cold in here or is it just me. Eskimo Dave.

kevinm
10-14-2007, 08:41 PM
... Gold is the only metal in the world that is a superconducter at ANY temperature...
And your proof of this is where, exactly? If gold is a superconductor at room temperature, then a bunch of companies are wasting a huge pile of money trying to develop room temperature superconductors.
http://environmentalchemistry.com/yogi/periodic/electrical.html

AfxToo
10-14-2007, 08:58 PM
Electricity does not flow through metal. It flows around it. Across the surface of it. I get a kick out of people advertising "Solid-rivet" chassis as if they are the greatest thing Aurora invented. The sad fact is the hollow rivet chassis flows electricity better because of the larger surface area of the hollow rivet. Granted, it's not a huge difference and wouldn't be either way. But some people just don't understand the laws of electricity.

Umm, yeah you are correct that some people don't understand the laws of electricity. If you are referring to "skin effect" then you'd better do a little more research. Skin effect only applies to alternating current (AC) transmission. Other than very high voltage and high current AC transmission lines skin effect is generally a concern only in radio frequency and microwave applications. It has absolutely no bearing whatsoever, none, nada, zilch, zero, on the differences between the use of solid rivets vs. hollow rivets in a slot car chassis running on direct current (DC).

Be careful when trying to apply isolated scientific theories or properties to real world products. There's a reason why most products are designed by engineers and not by scientists. There are several factors that have to be considered when translating scientific theory and properties into a product that can actually be manufactured, built cost effectively, and operated by mere mortals over a predictable service life under real world conditions (e.g. not at -200 degrees kelvin).

Likewise, if you really want to know how to get the most out of your race car, talk to the racers people who know to set them up and drive them effectively based on real world experience. Don't bother talking to your high school or college professor.

Hornet
10-14-2007, 09:40 PM
I'm pretty sure the skin effect applies somewhat to DC too Dave,welding cables and starter cables come to mind,many small wires are used to create a bigger surface area to conduct electricity.
DD,you're assuming a pure gold scenerio,i highly doubt the gold that's used to plate the copper parts with ,is a very good quality of gold

AfxToo
10-15-2007, 12:01 AM
No, never for DC. Find the skin depth equations by Heavyside (any shape conductor) or Maxwell (cylindrical conductor). You don't even have to do the math because the frequency component is in the denominator of the formulas. Plugging in a frequency of zero (DC) drives the skin depth to infinity, i.e., beyond the full depth of the wire.

Here's an online skin depth calculator. Plug in the frequency in kHz and it will return the skin depth. If the skin depth exceeds your wire thickness then it has no effect.

http://daycounter.com/Calculators/SkinEffect/Skin-Effect-Calculator.phtml

The only time skin effect would ever matter in a DC motor or coil application is when you are looking at the transient response, i.e., when the input is not DC. Even in this case the inductance of the windings would have a far greater impact on the total circuit impedance than the increase in resistance due to skin effect during the transient. Unless you're driving extremely high current coils used for conducting nuclear fusion experiments or something similarly drastic the transient skin effect will be negligible.

Welding cables and starter cables are stranded for greater flexibility. In fact, unless the individual strands in a stranded conductor are insulated from one another the skin effect of the individual strands, even in an AC application, would not apply. The entire cable would act like one big conductor with the skin effect of a single solid conductor.