Best way to sand out scratches to super-fine finish?

[stevenrosburg]

All,

First let me say that I'm complete newbie to this forum, and have no experience as a luthier. I do have some basic experience in carpentry and spray finishing, but nothing to the extent of members on this forum.

That said, I bought a cheap bass made in Korea a couple of years ago, and while I was pretty happy with the milling, the finish work was less than perfect. The nut was roughly cut and the neck did not have a pleasing feel to the satin finish. The gloss finish on the body was very good, though. I sanded down the offending edges of the nut with wet 400 grit wrapped over a piece of 1" PVC coupler, which allowed me to precisely remove material from the nut without touching the surrounding neck. After the rough material removal was done, I masked the neck and switched to 3M flexible polishing paper (600, then 1200), and that turned out very nicely. As the final step, I used a set of Micro-Mesh to lightly sand down the imperfections in the neck finish and bring it to a light gloss.

For my bass, this was perfect. The Micro-Mesh does a great job. So, I tried sanding out some light scratches out of the gloss finish on my acoustic. It worked well, but the resulting finish was still lightly scratched, even after the final grade of Micro-Mesh. I then used some Maguire's plastic cleaner (mild abrasive I already had for polishing my motorcycle helmet face shield) and that gave back most of the shine, especially on the pick guard. However, it's probably not the right nor the best tool for the job.

If I wanted to get the finish to absolutely glass-like shine with no visible scratches at all, can someone be kind enough to either point me to an existing article or outline the steps to achieve that final super-lustrous finish?

Many thanks in advance,
Steve

[FRANK]

buff with a buffer and I use rouge from grizzly .com buffing compound although I says it like its easy it is easily burnt through the color try some scratch remover auto motive brands McGuire #7 compound you can bounce between one McGuire in a heaver compound and old #7 this should help maby even go up to 12,000 in micro mesh and buff with the buffer and then go to McGuire I saw Frank Ford s buffer his has tons of buffing surface and is at a very low speed like 800 rpm he uses several wheels on the buffer for more surface

[stevenrosburg]

Paul,

Thanks for the info. I started the "rough" sanding at 6000 in Micro-Mesh and did go up to 12000, so the scratches are very faint, but they are plainly obvious when looking at the reflection against a well-lit background. Once I rubbed out the finish with the plastic cleaner compound, it made a huge difference, but it's still not completely glass-like. I am assuming a buffer is the next step I would need to take, but I don't own a buffer, have never used a buffer, and don't want to ruin my finish due to inexperience. If there's a manual (hand-rubbing) process that will yield better results that what I've already done, that would be my next step. Otherwise, if a buffer is the only way to go, any tips/articles on such for a first-timer would be welcome. Is the buffer something I could rent? What is the best way to get started? If I already have a close but not quite there finish (like I mention, I've already reached 12000 with Micro-Mesh and then rubbed it out finer than this), what compound(s) should I use, and what's the proper technique? It really looks quite good already, I would not be disappointed if it were to remain like this. However, I would like to learn what it takes to go the next step from good to flawless.

[FRANK]

stay away from paper towels and get a polish rag or a few of them or cotton T shirt cut it into squares some times bounce back and fourth through the micro mesh and go to hand rubbing put some elbow grease behind it and rub swrill patterns if the scratch is still there go back to a lighter grit micro mesh and rub that out and then go back to mcguires just remember not all scratches are alike some are already to deep to remove this takes experience and if it is a high dollar instrument then take it to a professional to answer your Q about rental I don't know I paid $500 for mine

[stevenrosburg]

Thanks again. I'm not trying to remove deep scratches, only light surface blems like pick scratches, etc. There is a ding in the finish and a couple of minor dents which I would like to have repaired, but depending on the cost I will leave that to a pro (or leave the dent alone). Yes, it's a fairly high-dollar instrument and I don't want to risk any damage to it.

[FRANK]

look for a luthier or a buffer or put some elbow behind it I don't think the plastic cleaner is any good to use never used it but the polish #7 and scratch remover from McGwires something to look at I am not even sure what kind of top coat you have in the first place but you can pop a tuner take a ear cotton swab dip in acetone test where the tuner was and if you pull top coat its a lacquer and if not its Polly Urethane you must know what you are working with cause one is more resistant than the other I worked for a finisher and a chemist who taught me that .Polly seams stronger and more forgiving and lacquer is not but just as easy to repair if you have Nitro so what we call millage or thickness is key taking in to mind color or natural I would say in general I work Polly scratches harder than I do Lacquer and have had to learn to fix my mistakes I have been doing finish for 9 years starting out in a small finish shop sanding uh i guess this brings my confidence up so when you are weary take it to a pro maby a luthier or a finish shop this sounds like these are your best bet

[stevenrosburg]

Paul,

When you say Meguiar's #7, I assume you are referring to Meguiar's Mirror Glaze #7 Show Car Glaze? Sorry, but I'm new to this and have no intention of becoming a luthier, just doing some basic home-care for my instrument. As for the scratch remover, are you referring to Meguiar's SCRATCH X 2.0, or some other product?

Also, since both of the above products are designed for hand application, I will probably stick with the hand-rubbed approach (assuming these are the correct products to use). Just out of curiosity, though, what kind of buffer do people use for instrument polishing? Is it the same as a car buffer (for example, Meguiar's Dual Action Polisher G110), or is this too fast for this kind of application?

Also, I have asked Larrivee what kind of finish is on my guitar, and they responded that they could tell me based on the serial number, so I should get an answer to that question later today. Are the products above appropriate for both polyurethane and lacquer, or are the specialized products for each?

Thanks again.