Yamaha classical guitar, factory matte finish, rough area

[Eduardo103]

Hi all.... I recently bought a new Yamaha Classical guitar, CG122 MC, nylon strings, delivered with a factory matte finish (normal for this model). The guitar's surface has a typical feel to my touch, except in one area on the sde that feels a bit rougher. I don't know whether this was just a slight factory defect in applying the finish, or whether the grain might be very slightly lifting. I'm pretty sure it's the finish in that area.

I'd like to address this issue, however minor. I was thinking a very light circular buff with 0000 steel wool, or perhaps some 2000 (or other grade) wet/dry paper, but I definitely could use some qualified advice for determining what the problem is and how to rectify it carefully.

After examining the area, it may have been buffed too much, leaving less finish - or - buffed too little leaving a slightly rougher finish in that area.

I believe the latter - not quite enough buffing (as at Yamaha they make a big deal out of the fact that they try to buff a little as possible, as they wish not to remove the very thin matte coating).

So if that is true - too little buffing - how can I now lightly buff that matte area. Thus my idea of light circular buffing with #0000 steel wool? Or is there a grade of wet/dry paper that might work? Last option: is there a wax that I can use just on the sides of the guitar (where this rougher area is)?

Gracias!

[Bizman62]

Hi and welcome!

First and foremost, the following is just my thinking, I'm by no means an expert.

If the problem area feels rough it might well be sanded too deep. The finish should have a plasticky feel even directly from the spray gun unless there's been an issue with the spray. Wood is normally sanded up to 400 or thereabouts before finishing and that's definitely rougher than a layer of clearcoat. I'd be very cautious with sanding!

Actually, there's a simple and nondestructive test to tell whether the finish has been sanded through or not: Simply apply a drop of water on the spot. If it stays on top, you can sand. If it gets sucked into the wood, don't sand.

One possibility is that the grain hasn't been properly rised by dampening between sanding. If so, the moisture of the finish may have caused the grain to rise like a hedgehog's spines. Unlikely but possible.

I've heard good reviews about Renaissance Wax

[Eduardo103]

On 3/30/2023 at 10:46 AM, Bizman62 said:

Actually, there's a simple and nondestructive test to tell whether the finish has been sanded through or not: Simply apply a drop of water on the spot. If it stays on top, you can sand. If it gets sucked into the wood, don't sand.

Bizman.... this is truly excellent advise and a key test that must be performed so as to minimize the chances of making things worse.   My first "droplet" test remained beaded on the rough spot as well as the properly finished areas.   Thank you.  I'll check out the wax...