Large Scale Central

Interesting post about brass

General Discussion
#1

This post turned up in a list I subscribe to. Its about wheel sets, but applies to our track, too.

—paste—

I don’t know what manufacturing processes IM and Jay Bee use, but brass bar
stock is not porous in the normal sense - at least not to the level of
magnification of the electron microscopes I have used. Its problem is that
common brass alloys contain about 40% zinc. At the microscopic level, the
zinc exists as separate islands of metal in the copper matrix. It does not
dissolve as salt dissolves in water. At content over (if my memory is
correct) 15% the zinc forms a continuous phase - it’s all pretty much linked
together. When exposed to a conductive liquid (sea water or bodily fluids)
the zinc oxidizes in preference to the copper. This is termed galvanic
corrosion. The zinc eventually dissolves, leaving behind a weak copper
sponge. I have been a boat builder, and just as in orthopedics, you never
use brass (or stainless steel) below the waterline of a vessel intended for
salt water service or contact with bodily fluids.

In normal use in our models, brass will not deteriorate into a sponge.
However the zinc will oxidize and deposit a non-conductive coating of zinc
oxide all over the surface. Nickel plating will prevent this problem -
until it wears off. I’m having all sorts of problems upgrading and
installing DCC in an old Akane model with worn drivers. Nickel silver is
actually a copper nickel zinc alloy with 15 to 25% nickel. If the zinc is
held below the limit where it is a continuous phase, corrosion is limited to
the small amount exposed at the surface. This wears off and you have a
conductive copper/nickel surface. Unless there is a couple percent of lead
in the alloy nickel silver is a pain to machine (I’ve not been able to find
a source of a free machining grade nickel silver), thus the preference of
some manufactures to use powdered metallurgy techniques.

#2

I guess I should stop bleeding on my track and running it through a salt marsh.

:lol: :stuck_out_tongue:

#3

??? you never use brass (or stainless steel) below the waterline of a vessel intended for
salt water service or contact with bodily fluids. " ???

Post is at odd with the facts:

Most large vessels have BRASS Propellers and some are mounted on Stainless Steel shafts. Every boat I have owned, many of which spent many hours in New England waters, had brass and or stainless props. Yes you do need to pay more attention to maintaining your zinc anodes and electrical systems.

Oh, And I have four Stainless implants.

As always, be wary of what you find posted online. However, no matter how tempting, the use of salt to deice your tracks is not a good idea. Especially if you run track power.

#4

Yea, I thought that was wrong about the brass and stainless. What I thought was neat was the bit about how zinc binds together instead of with the brass, and then when it weathers, it leaves the brass ‘porous’.

#5

Props and such for saltwater use are primarily bronze, not brass.
The bronze plaques on the Titanic will still be there long after the rest of the hulk is long gone.
Bronze coins have been found that are 100’s of years old in shipwrecks.
And so on…

#6

I have to challenge a few points here. Propellers are Bronze, not Brass and stainless is used extensively under water as the writer stated with his example of prop shafts and fastenings. I agree with the point of not using salt to de-ice your track, it will cause your simple electrolyte of fresh water to a stronger electrolyte being salt water, both less effective than battery acid, but the same principal. This actually falls under “Guano Happening” and is just something we all live with. The tarnish or patina on the brass forms a protective coating, so all is not bad. But polishing or cleaning has good results as well as bad as it wears a little away each time it occurs and you will eventually in a couple of life times turn it all back to dust. As much as most things in life, “all things in moderation” and the impact on your enjoyment will be minimal, which can be either a good or bad thing depending on your perspective.

#7

See, this is why I run Stainless track. I can piss on it all I want and it stays nice and shiny :smiley:

#8
Jon Radder said:
See, this is why I run Stainless track. I can piss on it all I want and it stays nice and shiny :D
New Englanders urinate in their yard in the public?? By God the horror of the thought !!!
#9

Jon, do you get a tingling sensation if the power is on?

Regards, Greg

#10
Greg Elmassian said:
Jon, do you get a tingling sensation if the power is on?

Regards, Greg


Is that what that is? I thought it was my spinal disorder acting up again.

#11

Gee like an electrical connection and get that funny fuzzy feeling. Later RJD

#12
Rooster Russell said:
Jon Radder said:
See, this is why I run Stainless track. I can piss on it all I want and it stays nice and shiny :D
New Englanders urinate in their yard in the public?? By God the horror of the thought !!!
Geeze and I thought that was just a Redneck thing......Yankees Do it too?
#13

sigh…

#14

Yep…its amazing what ends up a pissin’ contest around here…

#15

On Mythbusters, they tested the story that if you urinate on a live 3rd rail, you would get electrocuted. They showed that ot was not true.

Could it be that it is useful for melting the snow on the right of way?

#16
Bill Swindell said:
On Mythbusters, they tested the story that if you urinate on a live 3rd rail, you would get electrocuted. They showed that ot was not true.

Could it be that it is useful for melting the snow on the right of way?


I don’t know what the voltage level is between ground and the third rail but I’m pretty sure that urinating onto a high voltage source is not a good idea. Years ago a friend rigged up a spark plug coil (remember those?), an oscillator, a metal screen on the ground and one over his basement window. The idea was to discourage a neighborhood dog from watering his basement windows. Next day while making his rounds Bowser came to the booby trapped window, stepped onto the grounded screen and sent forth a stream onto the window screen thus completing the the 40,000 volt circuit. My friend claims the dog jumped ten feet into air and ran off yelping and has not been back for a visit since. Telling that story always makes me want to cross my legs.

Walt

#17
Bob McCown said:
sigh...
I didn't do it! I wasn't there! I was in another state. Yeah, that's it! :P :lol: :P
#18

Steve, I don’t know about you but I’m getting worried!

Paul

#19

I had a friend that had a vehicle with “mag” wheels, and the wheels were raw aluminum/magnesium… not chromed or painted or clear lacquered.

Dogs would pee on the mags and discolor them.

He hooked up a cattle fence “charger” to the body of the car, put the ground lead on the ground, and wet down the area… well that night, a dog completed the circuit… a loud yelp and the problem disappeared!

It works!

Regards, Greg

#20

It works but as for the 3rd rail issue. You ould hve to be bear foot, standing in water the rail grounded close to you and then you would have to have a stream that is unbroken why you piss on it. I saw the Mythbusters show that tested this one and there right it just real is not going to happen. Thing to keep in mind. Dogs are alot closer to the ground.

Now, stand in a muddy feild and grap that wire holding the cows in and your going to get zapped. Trust me I know.