The white banana

dswp · Post by **dswp** » Sun May 21, 2006 2:22 pm

Dear Curmudgeon;

While applying your special wax recipe today on my 1975 White 4080, I noticed something odd.

Under the pick guards, I can see that the white paint has turned to the banana yellow that is normal to see for that finish.

All the exposed areas are white as snow.

How is this possible, since the cause of the yellowing (I thought), was to be UV light and air contaminants?

All the pencil marks in the cavities are marked “white”, on top of the bare maple. No question in my mind that the guitar left the factory as a white finish. I first thought that maybe it was a refinish. Perhaps someone shot a new white finish and masked around the pick guards, perhaps to save the cavity graffiti. But there are no raised paint lines.

What say you??????????

jingle_jangle · Post by **jingle_jangle** » Sun May 21, 2006 2:57 pm

Pretty strange and I would certainly like to inspect that in person someday...

Offhand guess: Yellowed from degassing of the conversion varnish over a couple of decades plus?

I don't know how long you've had the white one, Dave, but another thought would be that possibly it all was a bit yellow, and the exposed parts were treated to a hand-rubbing with some polishing compound sometime in the past, which could have removed a yellowed surface layer.

kcole4001 · Post by **kcole4001** » Sun May 21, 2006 3:06 pm

My 4001 also has yellowed more under the guard. It's also a little less even than the exposed finish. It's not quite the color of a CS, but it's getting there. The masked parts are quite close.
There are definite wear spots on the back of the neck where the CV has worn through & the color coat is a nearly new looking white.

dswp · Post by **dswp** » Mon May 22, 2006 3:15 am

Paul, from my understanding of the white finish from the 70's....once it has yellowed, only a refin will correct it.

I would love to know if there is a process to remove the yellowing...

jingle_jangle · Post by **jingle_jangle** » Mon May 22, 2006 4:09 am

That's my understanding too, Dave. Hence my puzzlement.

My suggestion about the polishing was a shot in the dark, based upon the surface yellowing from contaminants which I've seen in some guitars over the years.

Third suggestion: the pH of wood. Wood is an acid material, and the acid in it (acetic acid, like vinegar) remains reactive for many years. It is a bit less acid than citrus fruit in some cases, with a pH of somewhere between 4 and 8. A reaction with the conversion varnish is possible. A concentration of acidity would occur wherever air circulation is inhibited, as in the area under the guard.

leftybass · Post by **leftybass** » Mon May 22, 2006 4:39 am

This is all facinating; it would be interesting to find out what was used on Andy Winter's RM 1999 formerly owned by Maurice Gibb, for that bass was finished in white many years ago, and is still white. The 70's 4000 on ebay at the moment still looks pretty white for an original finish.

wints · Post by **wints** » Mon May 22, 2006 9:02 am

I asked Paul that a while back....given that it was refinished in 67, but now I've forgotten what he said!

One more time please Paul..

jingle_jangle · Post by **jingle_jangle** » Mon May 22, 2006 9:21 am

Andy, we never established if it was yellowed under the guard.

I do remember talking about it possibly being finished in acrylic lacquer? Did that maybe jog some memory cells?

Beyond that, I think there was more than one CV formula at the time, there's the issue of whether it may have been refinished, whether it was stored for a long time, etc.

An in-hand inspection might put an end to this speculation, in any case.

doctorwho · Post by **doctorwho** » Mon May 22, 2006 10:31 am

My 1975 4001S WHT is uniformly yellowed, i.e., there is no difference in the finish under the pickguard:

This one has spent most of its life in the case, so it has not had much exposure to sunlight or atmospheric pollutants. It is definitely yellow when compared to my 1998 4003 WHT WT:

jingle_jangle · Post by **jingle_jangle** » Mon May 22, 2006 11:19 am

Or compared with its acrylic guard, which has not yellowed (nor will it).

The more I think about this, the more I am convinced of the complexity of the contributory factors and their combinations.

There must be at least one, possibly more, different paint/clearcoat formulations involved in this. There's the type of sealer used on the wood. There's the varying acidity of the wood itself, and lastly there's the infinite range of atmospheric and climatic factors.

leftybass · Post by **leftybass** » Mon May 22, 2006 12:49 pm

Some have yellowed so bad they've been called 'Nicotineglo', LOL....

dswp · Post by **dswp** » Mon May 22, 2006 12:56 pm

Example

wints · Post by **wints** » Mon May 22, 2006 1:17 pm

Paul, that sounds right. Acrylic lacquer.

There is no yellowing anywhere, including under the guard. Not bad considering it's coming up for 40 years...

winston · Post by **winston** » Wed May 24, 2006 12:11 pm

My entire 1976 4001 bass has yellowed. It has the original white factory finish on it. The yellow effect is darker under the pick guard and TRC though.

Does that information help or just confuse things even further?

jingle_jangle · Post by **jingle_jangle** » Wed May 24, 2006 12:22 pm

I'm willing to bet that both atmosphere and the pH of the wood acting on the conversion varnish are what's responsible for the yellowing.

Look at Dave's headstock picture above. Note the small rectangle of pure white paint in the truss rod recess, No yellowing. I'd bet that it escaped conversion varnish at the factory. There was some tape applied over the assembly when the CV was sprayed (it builds up), hence no CV in the pocket. The white acrylic lacquer stayed white.