Can yellowing be hastened?

[tevitag]

I've read up a fair bit about yellowing of varnish (necks and headstocks particularly) and there are many views about the natural ageing/yellowing of wood varnish. But for those of us who like yellowing, can the process actually be sped up?

I've thought about putting the guitar in the sun for a couple of hours a day. But has anyone tried blacklights? Are the UV rays from blacklights the right ones to yellow the varnish, and would this be a quicker process if the guitar was exposed to blacklight for extensive periods of time?

Really interested to hear your thoughts on this!

[kaiuk]

you could apply some darker varnish if you are into that sort of thing

[Pilgrim]

A bit of coffee applied judiciously will stain...but you'll have to watch to keep it even.

[Phendyr_Loon]

I just put a maple fretboard neck on a jazz bass I've been working on.
I'm also going for a aged/yellowed/darkened look, so I'm leaving the bass out of the case on a stand in a room that gets a lot of sun.
I'm obviously not expecting an aged vintage look by next week, nor am I into applying more finish to my neck. I do love walking into a guitar shop and seeing a P or J with a nice sun kissed FB hanging on the wall.
Mine will come in time.

[cataract]

Chain smoke in a room with glass walls?
Repeatedly? Perpetually??

[Ric5]

Ultraviolet light.

[Caca de Kick]

If you know any smokers, leave the body and neck in their car.

[cataract]

Originally Posted by Caca de Kick

If you know any smokers, leave the body and neck in their car.

Huh?! Ah..
It's official: I've been playing way too much L.A. Noire.

[Staccato]

My attempts have been successful indoors in direct sunlight through large windows without UV protection. I would not recommend 24/7 exposure, and you should consider personally supervising this-away from kids, cats, or other critters.

Lately, I've tanned-mostly maple frets, or maple on back on necks-indoors in direct sunlight.

[Corey Y]

Leaving a neck out in the sunlight would probably do the trick, although there's no telling how long it would take or how consistent the results would be. What sort of finish is used on the neck would have some bearing on that. A UV lamp could probably work, might require a bit of setup and tinkering. Whatever you do I'd try it on something you don't mind fudging up first and experiment. At worst I think you'd just get an inconsistent patina to the finish or just not a very noticeable difference. If you leave it in the sun all day and it's a scorcher and the wood isn't of a particularly good quality or wasn't properly dried it could bow or twist a bit, but you'd probably only be accelerating the inevitable then.

[tevitag]

Thanks for all the interesting comments and information. Coffee? Wow I had never heard that one. I might even end up trying some combinations because I do have a bass to experiment with. And I hope to report back sometime in the future with results!

[bassbenj]

Originally Posted by Ric5

Ultraviolet light.

ultraviolet light is certainly a component, but not the whole story. Testing labs that test finishes for sunlight aging have these huge ultra bright arc lamps to simulate sunlight and accelerate the process so it doesn't take forever. Still summer sun (the real thing) is pretty strong and can work in a reasonable time.

I've got a high powered mercury vapor lamp I used to use for making PC boards (basically a mercury vapor out door lamp with the UV absorbing glass bulb broken away). I don't know how it would work but I do know it tends to scorch things rather than just yellow them. The fluorescent type blacklights seem to put out much too little light to be useful.

Note that when you are talking about yellowing of maple, it the wood and not the varnish that yellows! What happens is that over time oxygen in the air oxidizes the sugar in the maple turning it brown (like cooking Caramel). I have very successfully matched real aged maple with new white maple using the stain called "colonial maple". It also matches the stain used on many new bass necks with a "vintage" tint.