Why is my guitar rusty?

timmypix · October 2023

First, the pics, then I'll provide the context:

I got this guitar new in 2009 and always looked after it well. Cleaned it every restring which was more or less monthly, really looked after it. Then it was stolen in 2017. I got it back in October last year, and it came back looking exactly like the pics above. Given that it had lost the case it was stolen in during those 5 years, I assumed it had been kept badly, cleaned it up and put new strings on it.

It lived out for a bit, then we had to redecorate my office which has been slow, on-and-off progress, so it went into its case in January/February time and came out last night, and the pics above are how it's emerged!

It's been in the same room as all the other guitars for all this time, there's a pack of silica gel in the case and there's no dampness or corrosion in the case itself, so I'm utterly baffled.

The corrosion is only on the headstock - strings, screws, washers, tuners, machine heads. Below the nut it's as clean and fresh as when it went into its case. Those were pretty much new strings when it went into the case.

Any ideas? I haven't cleaned it up yet as I wanted to present this mystery, and given that I already did this last year, I'm conscious I may need to do something more preventative than just scrubbing.

ICBM · October 2023

Did you leave a celluloid pick anywhere near the headstock, eg wedged in between the wound strings?

That looks like nitric acid outgassing damage - notice how it's only attacked the nickel plating and not the steel plain strings, and only on the headstock and not over the fingerboard. Celluloid can do that, although it's usually only really old celluloid pickguards.

I did wonder about the truss rod cover, but it's not as bad right next to the nut. (And anyway I don't think it's celluloid.)

Or could something not easily detectable have been left in the case lining there?

OilCityPickups · October 2023

ICBM said:

Did you leave a celluloid pick anywhere near the headstock, eg wedged in between the wound strings?

That looks like nitric acid outgassing damage - notice how it's only attacked the nickel plating and not the steel plain strings, and only on the headstock and not over the fingerboard. Celluloid can do that, although it's usually only really old celluloid pickguards.

I did wonder about the truss rod cover, but it's not as bad right next to the nut. (And anyway I don't think it's celluloid.)

Or could something not easily detectable have been left in the case lining there?

I was about to say acid fumes damage ... a few years ago I used nitric acid to relic some hardware and it looked just like this!

timmypix · October 2023

Interesting, thanks both. No celluloid picks in the house, so it's not that!

And FWIW, it's chrome plating, not nickel, if that makes any difference?

Some extra info to confuse things then. I have two identical guitars (as in, sequential serials!) and before this one came back, its twin lived in the exact same case long term - also for months at a time. Same truss rod cover, same case, no corrosion.

Although if, during its 5 year absence, it was stored with a celluloid pick that did the initial damage, could that make it more susceptible now even with no such thing obviously around? It also spent at least some of its absence in Blackpool without a case - sea air? Not much of that here in Birmingham, mind, but could it be more susceptible to corrosion having corroded previously...?

Brio · October 2023

You are zombie Rory Gallagher.

ICBM · October 2023

timmypix said:

And FWIW, it's chrome plating, not nickel, if that makes any difference?

Yes, I saw that the machineheads are actually chrome plated, but chrome is plated over nickel and somehow the corrosion has got through the chrome layer - that's why the residue is green, which is the colour of corroded nickel (nickel nitrate, when exposed to nitric acid) - which is very typical of outgassing damage.

Why the wound strings have gone a more typical 'rust' colour (typical of corroded iron, ie steel) I'm not sure - especially as the plain strings, which are definitely steel, have not.

Although... I have just discovered that there's a form of chromium nitrate which is also green! I thought it was black. So maybe that is actually the chrome corroding.

thermionic · October 2023

And FWIW, it's chrome plating, not nickel, if that makes any difference?

Metal parts are usually nickel plated under the chrome, and on a microscopic level, chrome is quite porous.

timmypix · October 2023

Thanks @ICBM, understood!

It won't be going back in the case for a while now, so I guess I clean it and hope it doesn't come back.

Dr_Necessiter · October 2023

Because it gently weeps?

skunkwerx · October 2023

I have never seen anything like that before!

I've got a couple of LTD's myself and whilst theyre always stored out, my room gets quite dusty and I have neglected them for months before with zero issues whatsoever.

Hope you get to the bottom of it mate. That really sucks.

elstoof · October 2023

Might the thief have stashed it in a lockup with some sort of chemicals that are still lingering on the guitar

digitalkettle · October 2023

elstoof said:

Might the thief have stashed it in a lockup with some sort of chemicals that are still lingering on the guitar

Meth lab!

timmypix · October 2023

elstoof said:

Might the thief have stashed it in a lockup with some sort of chemicals that are still lingering on the guitar

Thankfully not this one; another did come back stinking of weed and trainers and my only way around that was to stuff the case with dryer sheets!

Offset · October 2023

I think the thief was Dorian Gray.

timmypix · October 2023

Offset said:

I think the thief was Dorian Gray.

I did put the case in the attic before I made this post.

Teflon · October 2023

You say it came back to you looking like it does in the photo. I would suggest that whatever caused the corrosion in the first place has compromised the plating in that area. You can clean it off, but if left alone for any period it's always likely to return.

Cliff

guitarjack66 · October 2023

Another one of those strange people that name their guitars!

timmypix · October 2023

Teflon said:

You say it came back to you looking like it does in the photo. I would suggest that whatever caused the corrosion in the first place has compromised the plating in that area. You can clean it off, but if left alone for any period it's always likely to return.

Cliff

That is my fear. In which case I may need to replace the tuners, I assume.

CampbellH · October 2023

Initially chromium oxidises forming a thin layer of the oxide on top of the metal and that prevents oxygen getting deeper into the metal protecting the other metals underneath. Passivation. If that layer gets damaged then oxygen will seep further in to the metal structure. This would give rise to the underlying metal oxidising. This is what happened in old cars with chromed over steel bumpers when you saw rust blisters, similar to what you have here.

timmypix · October 2023

CampbellH said:

Initially chromium oxidises forming a thin layer of the oxide on top of the metal and that prevents oxygen getting deeper into the metal protecting the other metals underneath. Passivation. If that layer gets damaged then oxygen will seep further in to the metal structure. This would give rise to the underlying metal oxidising. This is what happened in old cars with chromed over steel bumpers when you saw rust blisters, similar to what you have here.

Thanks!

Let's hope replacing the tuners sorts it then.

Howdy, Stranger!

Categories

In this Discussion

Become a Subscriber!

Why is my guitar rusty?

Comments