Guitar Finish Thickness & Tone

[Flyyaker]

I have a Epiphone AJ200S and the finish looks very thick. If I took the time to sand this finish down to make it thinner would it have a positive effect on the tone of the guitar? Has anyone ever tried this?

Thanks, Rob

[Frank Ford]

I wouldn't expect any significant improvement.

[Ned Milburn]

The finish is called that for a reason - it is finished, and rarely is it worth the extra cost or effort. Some people have reported DIY success, however... usually when there has been an interest in the crafting side as well.

[Mr Fingers]

Sanding back a finish is an iffy proposition because you can't really be sure when you're getting close to the wood. And playing it safe means leaving too much finish anyway. As Frank Ford stated -- and he knows more than most of the rest of us combined -- the process, even if done without any messups, is unlikely to yield an audible difference. You would be better off removing all the finish and doing a thin refin, if you really want to see if you can change the tone. But underneath it all, it's an Epi. A miracles is unlikely. I'd leave it as is and sell it if you really don't enjoy it.

[Trevor Gore]

I'll give you a different perspective...

I was doing some consulting work for a guitar factory in Asia. When I was touring the plant with the management hierarchy, I was randomly pulling guitars off the line and tapping them (as guitar builders are wont to do). The puzzling thing was that prior to the finishing department all the guitars sounded "normal". What "normal" is you only know if you've tapped a lot of unfinished guitars, so really it's only something an experienced guitar builder would recognise. After the finishing department, everything sounded "dead" when tapped, and that corresponded to the finished sound of the strung instruments. Further, the "higher quality" instruments (premium woods, shinier finish) sounded most dead. After a bit of investigation, I discovered that the "higher quality" instruments essentially went through the finishing department twice, to make sure the finish was as perfect and shiny as possible, with the consequence that they had almost twice the finish thickness on them as the less expensive guitars.

I discussed this with management and arranged a blind listening test. 6 guitars were pulled from finished goods covering the range of models from low budget to quite expensive (including some that had two trips through finishing). I introduced another guitar, which was of all ply construction, (i.e. bottom of the range) that was not finished, just pulled from the line prior to finishing, had a bridge stuck on and was strung. Two different players played all the guitars in random order and the company board was asked to rate them in order of preference, where "preference" was to include at least musicality, loudness and clarity, without knowing which guitar they were listening to. The board members were doing this individually, but their results were all very similar in terms of ranking.

The unfinished guitar was way ahead of all the others, and the "double finished" guitars (which, remember, were the company's premium offering) were way behind.

Now, you can get picky with the test set up (wasn't double blind, wasn't this, wasn't that, blah, blah) but what was undoubtedly obvious to me as an "expert" and to the board (who were expert business men, rather than expert players or makers) was the night and day difference between unfinished and heavily finished guitars.

Needless to say, there were consequences. The finish, BTW, was predominantly polyester.

[redir]

That's a great story Trevor.

I don't think I would bother refinishing that Epiphone either but one thing I do notice along the same lines that Trevor is talking about is that when you apply the finish to the guitar something chances. I'm not even really sure what it is but something changes and you can hear it when you tap on it and billow in the sound hole. So having said that, it's proof enough to me that the finish does at least something to the tone and one could hazard a good guess that a thick one would be detrimental. And those cheaper import guitars are notorious for thick finishes. It's most apparent when you they come in for a bridge reglue repair. They glue the bridges right to the finish so you have to remove the finish to bare wood to do it right and it's pretty amazing how thick it often times is.

I started French Polishing a few years ago and I'd swear that those are the best sounding guitars I have made to date. Of course they are successively later builds with more experience behind them too so I don't know. None the less intuitively thin seems better for sound yet worse for protection and vise versa and Trevor's story adds a little experiment to support that.

[Flyyaker]

I picked up this guitar for $80 because it had a top crack and have been playing around with it like shaving the bracing and fixing the crack. The brace shaving made a noticeable difference, the top crack repair was just fun to do. So I was considering experimenting with the finish. Thanks for all the insight.

[Truckjohn]

On the finish - sure.... Give it a go... If the finish is thick - reducing it will make an improvement in tone.

The trade off is as listed... It's going to be ugly after you do this... Resale just went to zero... You can easily sand through...

Also - unless you have all the fancy finish equipment - it's very difficult to do a good job on a guitar finish. It's a very exacting finish.

A comment here... Since you mentioned brace shaving..

I know this will be a bit off the original topic - but don't neglect the back braces when you are looking for irreversible changes you can make that can have some very good effects on the tone.

With shaving the back bracing....
1. It works
2. Significantly less risk of the top cracking or the bridge peeling off...

Thanks

[redir]

Shaving braces will have a much bigger impact on tone then refinishing. Sounds like you bought yourself a project guitar, something to learn on. Good idea. I say go for it. You will want to remove the bridge in order to refinish it. You really only need to refinish the top if tone is your primary consideration imho. I would use a stripper like 'Aircraft Remover' to chemically strip the finish. That will save you a lot of sanding. I don't see why you can't get a good quality refinish on it. The only tricky area will be around the fretboard extension but since that is with the grain anyway then you should be able to buff right up to it.

[Alan Carruth]

What Trevor said.

A lot depends on the finish. Generally speaking all finishes add mass, and most add cross grain stiffness to the top. Some can add significant damping, while others actually have lower damping than the wood, at least in the cross direction, and so can make it 'better'. I'd say that when the finish is thick it really doesn't matter what it is; it's hurting the sound.

On the other hand, you can't make a silk purse from a sow's ear. If the guitar itself is not that good removing the thick finish probably won't help it much.