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I'm in the mid 20's on guitar builds now and all but 3 have been Sitka tops. I've noticed that there is a lot of variation in how much the color of the tops darken with age. I really can't see much difference in the color on the freshly thicknessed tops when I'm starting a new build - they have all seemed very similar in color - but some have darkened much more than others over time. I have used the same finish on all guitars - McFadden's nitro lacquer. My question is 'can you tell from looking at a "fresh" top how much it may darken with age?'.

Chuck

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"To live a creative life, we must lose our fear of being wrong"
- Joseph Chilton Pearce

Could it be some tops have been exposed to more sunlight than others since leaving your shop?

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Formerly known as Adaboy.......

If you are looking to consistently replicate that mellow old finish look you will need to do a bit more than just lacquer. You could start with a coat or two of one of the darker shellacs, like garnet, as a sealer. Play with the cut to get the shade you want. just make sure it is de-waxed so the lacquer will bond. Or you could add a touch of tint to your lacquer, but the overall tone will be determined by number of coats and their thickness. Another option would be to apply a coat of glaze after your first few coats of lacquer, this could not only impart color but also mimic patina if done correctly. Then of course you could always stain or dye your tops prior to finishing. Best advice is to start doing some samples on scraps from your soundboards until you find what works for you and gives the desired result. Bear in mind of course no two pieces of wood are the same and there will always be differences and variations....that's the natural beauty of wood.

Brian

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

The darkest shellacs do a great job but it is a bit difficult to keep it even.
Alternatively, you could take it to a tanning bed. Here is how several grades of UV exposure (8, 30, a bunch of hours) in my (low power) booth look like.

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Build log

Not Sitka, but I'm french polishing my latest, and I'll take it outside in the sun, sorta to "harden" the build.
I think sunlight must quickly affect either the spruce or the shellac.
As far as adding color with shellac, be sure to do the first coats with shellac with no added tints or dyes, just natural.
Even the darkest color shellac doesn't seem to be strong enough to blotch spruce, but added tints do.

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I'm more interested in being able to avoid a situation where a top darkens more than a customer wants and he/she ends up disliking the overall look of the guitar. I know I can't control what they do with it after it leaves my shop, but I have two of my early guitars that have stayed in the same room - literally next to each other on stands - for 3 years and one is quite a bit darker than the other. I also know that if a customer wants it to stay light in color, there are other species of Spruce that I can choose.

I'd just like to be able to look at a new top (after thicknessing where it is freshly sanded) and be able to tell if it's going to darken a little or a lot. Maybe it's not possible...

Chuck

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"To live a creative life, we must lose our fear of being wrong"
- Joseph Chilton Pearce