Brassing

[chainwhip]

Hey gang-

 

I'm just curious why trim/clips/etc., tend to "brass" over time (even just sitting in storage)? Are there any good ways of removing the "brassing"?

 

Is it oxidation? I'm curious...

[PaulLeMay]

Most of these parts are brass with a thick coating of gold (gold filled). Brassing is when the gold layer is physically worn away, exposing the brass beneath.

 

The only way to correct it is to electroplate gold on top of the exposed brass area, much easier said than done.

[kirchh]

Generally, brassing is the exposure of the base metal (or an inner layer) of a metal part due to the wearing away of the decorative coating material. The base metal is typically brass, plated parts may have an intervening layer of nickel, and the coating is often gold or an alloy thereof.

 

In my experience the largest contributor to brassing is polishing (power buffing), which can remove as much material in five seconds as would a year of average use (I am not exaggerating. I don't exaggerate.)

 

Brassed parts may be electroplated to restore the appearance of the decorative surface. though the resulting part's composition may be at variance with the original structure and the parts may not wear as well as would gold filled components. It may also be possible to use a laser welder to replace worn-off material, though I speculate here.

 

--Daniel

[chainwhip]

Thanks for the responses... I wonder if water (as in after cleaning, not getting all the water dried from the underside of the clip) would contribute to Brassing?

[chud]

Shouldn't, I wouldn't think (but I'm no expert). If the part in question has no brassing at all then it should be completely covered in a layer of gold, which will not oxidize. (Is the underside of a GF clip also gilded? I assumed so but I don't actually know.) In order for water, air, or other reactive things to have any effect they have to get under the gold or get rid of the gold first.

 

It's certainly possible that the gold fill/plate process might not be complete, leaving some uncoated brass exposed somewhere, and oxidation could start there, but I think brassing as it's usually seen is almost always the result of physical wear. That could be daily use, years of intermittent use, overly enthusiastic cleaning or polishing, or whatever, but in all cases it means the gold layer is physically worn away.

 

If an old pen has been in a box or drawer for most of its life, I wouldn't expect to see any significant brassing.

 

But, it bears repeating that I'm no form of expert at all.

Edited October 25, 2006 by chud

[*david*]

I don't think parts "brass" at all when in storage, unless the storage consists of being tossed around and rubbed. I may be wrong, for I am no expert either. I suspect that a significant number of cases of brassing are as a result of overzealous polishing.

 

Edit: and I suspect that the "year of damage in five seconds" is a significant understatement. I have in front of me a pen from the '40s that looks just fine. If I buffed its clip five seconds for each year that pen has been around, there wouldn't be much of a clip left at all.

Edited October 25, 2006 by *david*

[Gerry]

Pretty reasonable assumptions Chud. In my experience, brassing is almost always associated with abrasion, either as Daniel has said, polishing or just plain handling.

 

I don't think that brassing as a result of oxidation, chemical reactions or anything similar accounts for more than an insignificant % of any of the wear seen. Most is on protuberances that are exposed to wear, or are naturally associated with wear. The former would be raised portions of the pen clip, the latter, the inner part of the ball of the clip.

 

I caused brassing in some of my pens with the habit I had of rotating the pen on the pad of paper. The abrasion of the paper wore the thin gold plating off of the clip (not on the ball area), and this had nothing whatsoever to do with polishing...

 

Regards,

 

Gerry

 

Edit: Changed Richard to Daniel (yes, difficult, I know, but I did it anyway), as I had the attribution wrong...

Edited October 26, 2006 by Gerry

[psfred]

Or might you refer to things turning green rather than base metal showing through often very thin gold plating?

 

This is indeed corrosion, usually a result of nasty things in the air. Lighting matches so that you can smell them in the house to light fireplaces, etc will corrode lots of things, and badly tarnish silver!

 

Peter

[Gerry]

Or might you refer to things turning green rather than base metal showing through often very thin gold plating?

 

This is indeed corrosion, usually a result of nasty things in the air.  Lighting matches so that you can smell them in the house to light fireplaces, etc will corrode lots of things, and badly tarnish silver!

 

Peter

Certainly possible, I have had rings and some watches exhibit this corrosion - usually due to perspiration and skin contact. It is less often seen in fountain pens, and is not referred to as brassing if it is seen.

 

Regards,

 

Gerry