Nickel plating brass on instruments

[mewstone]

As a part of the thread "GWR Cow Bell or sheep dome bell?" JRB posted the following:

Post by JRB » Sun Jun 19, 2016 9:59 pm

"I don't know if any block bells suffered, but it was common for any brass item reaching the telegraph shop for overhaul to be put through the dull nickel plater."

A friend of mine has recently purchase a White & Co manufactured ex GWR turned stem block "Church" bell. On polishing the turned stem he has been surprised that the metal coating has rubbed off and that it has exposed solid brass underneath. I was wondering was it just a Reading Signal Works policy to nickel plate brass items upon overhaul, or was this done by other companies/regions and does anyone know dates for when this policy occurred and why it was done. Surely if brass is not polished it would go dull anyway. I was just wondering what the benefit of doing this was?

[Fast Line Floyd]

Probably to put the signalman off polishing it and so saving on brass polish!

[John Hinson]

I was wondering was it just a Reading Signal Works policy to nickel plate brass items upon overhaul, or was this done by other companies/regions and does anyone know dates for when this policy occurred and why it was done. Surely if brass is not polished it would go dull anyway. I was just wondering what the benefit of doing this was?

Some Midland blocks were so-treated too, so the practice was not limited to Reading works.

From https://en.wikipedia.org/wiki/Nickel_electroplating :

Nickel electroplating is a technique of electroplating a thin layer of nickel onto a metal object. The nickel layer can be decorative, provide corrosion resistance, wear resistance, or used to build up worn or undersized parts for salvage purposes

It was often classed as a challenge to rub it away to the brass so it certainly didn't save the brasso!

John

[John Webb]

Resurrecting this year-old thread, at St Albans South we're restoring a further pair of bells for demonstration purposes, one of which had a nickel-plated bell. Trying to clean it up a bit with Brasso, the surface seemed to react with the Brasso and became really grotty. Using fine grade wet and dry paper in wet mode we've removed the grot but ended up with a polished nickel surface, which is not quite how the bell once was.
This however has lead to one of these conservation problems we get faced as a museum, hence my writing here. Is there any way of restoring the dull appearance, or to judge from the above, would it be prototypical to take the nickel plate off completely?

[JRB]

Original - brass
After overhaul - dull nickel
After TLC from signalmen - bright nickel

Which is authentic for the museum?

[John Webb]

It wasn't a bell actually used in the box. So perhaps we'll keep it as it now is as an example of what was sometimes done. Or am I taking the easy option?

[Mike Hodgson]

Original - brass
After overhaul - dull nickel
After TLC from signalmen - bright nickel

Which is authentic for the museum?

This is rather like asking what is correct for a model railway - you might be told we want it as per (say) the 1950s - which doesn't help make it exact, because one loco (or block bell) might be correct for 1/1/1950, whilst another is correct for 31/12/1959, but the two did not co-exist.

I would suggest the authetic historical date for a heritage signal box "ought" to be the date of the box diagram, assuming it is dated, and the box could only ever be historically accurate if you were able to establish all of the details of each piece of equipment, track layout etc on that single date. In practice of course you would find it impossible to establish exactly when many particular details changed.

In any case a museum box like St Albans South is far more interesting if you can demonstrate both later and earlier practices and equipment (Rotary vs conventional instruments, more/less sophistication of block controls for example.) Let's not forget that the box is not and cannot be historically accurate in that it has already been modified for various good reasons. It only features part of the frame, that ugly extension collapsed and an accessible toilet has been provided, it never operated signals facing away from the line in a garden, and of course it wasn't open to the public!

My comment to John Webb is that it really doesn't matter; if you want to make polish a talking point for visitors, you could have one of them gleaming and the other left unpolished. But do you really want to spend every open day polishing a lot of brass, plated or otherwise?

[John Webb]

Thanks for your comments, Mike. Several of us looked at it tonight during our social get-together and we've decided to leave it as polished nickel.
I don't know if it's because the box is only gently heated, but we don't seem to have to polish the brass every time we're open - usually a month between polishes (done on our working party afternoon) seems to be adequate.

[Danny252]

I don't know if it's because the box is only gently heated, but we don't seem to have to polish the brass every time we're open

I've generally found that brass very rarely needs any attention other than where fingers touch it! Brass plaques and the like do quite well with polishing only a couple of times a year at Exeter West, and that does suffer quite badly from condensation in the winter months.