How can I remove scratches in a poly finish? Micromesh? Polishing compound and swirl remover?

Stagelab

Stagelab

Dec 26, 2015
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Queens, NY
#1
There are some scratches by the bridge. I can’t feel them but if light hits at certain angles I can see them. Finish is a gloss poly black metallic sparkle.

What would you recommend to reduce the scratches? I just don’t want to leave an indentation. Oh, and I don’t have a sander, I’ve only sanded by hand before.

I have lots of high grit sandpaper up to 10,000 grit but I don’t know if regular sandpaper would be a smart choice (for wet sanding) vs Micromesh or medium/fine grit polishing compounds followed by swirl remover.
 

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#2
i'd def use the latter materials you mention..Micromesh,wetsand,swirly remover. Plus its a sparkle finish so extra careful, and hand sand only for that small area. Lots of how-to vids techniques and products out there. Yours appears to be scratches on the poly and not a crack, luckily.
 
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#5
What grits of the micromesh would you suggest I use for wet sanding? Is 1000 considered medium? I found kits with pads up to 10,000.

For kicks I tried my girlfriend’s jewelry polishing cloth but it didn’t help. I think it’s less abrasive than the jewelry pads.
 
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#6
Found this conversion chart for micro mesh. Looks like 4,000 equals 1500 regular sandpaper. Maybe that’s a good place to start?

micro-surface.com

Grit Conversion - Micro Surface

Use this CONVERSION CHART as a guide to know when you can start using MICRO- MESH™. Use conventional abrasives as normal prior to going into the MICRO-MESH™ stage. It is advantageous to use MICRO-MESH™ as soon as possible in your finishing process as it gives a more consistent scratch pattern...
micro-surface.com micro-surface.com
 
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#8
Stagelab said:
Found this conversion chart for micro mesh. Looks like 4,000 equals 1500 regular sandpaper. Maybe that’s a good place to start?

micro-surface.com

Grit Conversion - Micro Surface

Use this CONVERSION CHART as a guide to know when you can start using MICRO- MESH™. Use conventional abrasives as normal prior to going into the MICRO-MESH™ stage. It is advantageous to use MICRO-MESH™ as soon as possible in your finishing process as it gives a more consistent scratch pattern...
micro-surface.com micro-surface.com
Click to expand...

That sounds way too aggressive, IMHO.

Always start lighter than you think you need. I would try a light rubbing compound myself. That said, I would wait for some of the builders/luthiers up here to chime in before I did anything.
 
#9
Zooberwerx said:
Lot of potential to make things worse so proceed with caution. I'd start with something like 3M Finesse-It polishing compound. It will definitely reduce the appearance. Past that point, I'd park my OCD and live with it.

Riis
Click to expand...
Thanks, sounds good. I found a few different 3M Finesse products. Can you post a link to the one you’re referring to? Do these products usually leave swirl requiring a separate swirl remover?

Maybe the best approach is to try a polishing compound first and if it doesn’t help, get a light rubbing compound and apply it followed by the polishing compound.
 
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#10
Stagelab said:
Thanks, sounds good. I found a few different 3M Finesse products. Can you post a link to the one you’re referring to? Do these products usually leave swirl requiring a separate swirl remover?

Maybe the best approach is to try a polishing compound first and if it doesn’t help, get a light rubbing compound and apply it followed by the polishing compound.
Click to expand...
Finesse-It II Machine Polish P/N 051131. It’s all rubbing compound of some type but with varying grit. Polishes come into play when removing swirl marks introduced by the heavier-cut compounds. Keep in mind we’re probably dealing with scarring of the clear coat and don’t want to rub thru that. I use the same stuff to remove swirl marks from polycarbonate headlights.

Riis
 
#11
Zooberwerx said:
Finesse-It II Machine Polish P/N 051131. It’s all rubbing compound of some type but with varying grit. Polishes come into play when removing swirl marks introduced by the heavier-cut compounds. Keep in mind we’re probably dealing with scarring of the clear coat and don’t want to rub thru that. I use the same stuff to remove swirl marks from polycarbonate headlights.

Riis
Click to expand...
I found that product with 051131 but it’s over $80 a bottle. Way too expensive. Is there an affordable alternative?
 
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#13
Chop11777 said:
I would go to the automotive parts store
Get a 3m scratch removing kit
It's got a foam pad for your drill and compounds
Go easy and work out the scratches . Or meguires ultimate compound by hand should work it out
Shoot us some pics !!!
-chop!!!
Click to expand...
I think I’m more comfortable doing it by hand so I can ease into it even if it takes much more work. How coarse is Ultimate Compound on the scale of rubbing and polishing compounds? The product descriptions all sound similar.
 
#15
Stagelab said:
I think I’m more comfortable doing it by hand so I can ease into it even if it takes much more work. How coarse is Ultimate Compound on the scale of rubbing and polishing compounds? The product descriptions all sound similar.
Click to expand...
Meguires ultimate compound is my go to
It's not real aggressive and the more you work it the better it looks
Can't in my opinion really do any damage with it
Chop!!!
 
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#16
A different thought: any merit to adding material instead removing it? I think of buffing a surface down, especially something like clear over sparkle, as being limited to maybe a few times. Perhaps wax or some sort clear self-adhesive option where it’s prone to contact/wear.

On one instrument, I have a small amount of packing tape protecting a vulnerable area, long-term temporarily. An idea…
 
#19
Stagelab said:
There are some scratches by the bridge. I can’t feel them but if light hits at certain angles I can see them. Finish is a gloss poly black metallic sparkle.

What would you recommend to reduce the scratches? I just don’t want to leave an indentation. Oh, and I don’t have a sander, I’ve only sanded by hand before.

I have lots of high grit sandpaper up to 10,000 grit but I don’t know if regular sandpaper would be a smart choice (for wet sanding) vs Micromesh or medium/fine grit polishing compounds followed by swirl remover.
Click to expand...
Im wondering out loud is this a show piece? Like once you finish taking care of these scratches, is that it, bass in glass case and retired hung on the wall?
 
#20
All good advice here, for a small area like that, start by hand with a microfiber cloth and some swirl remover. You can always go more agressive, fine polish compound next up the scale, micro mesh finest pad if that doesn’t work. I doubt you’ll have to go beyond fine compound. You should be able to find McGuiars at any auto parts store or Amazon for cheaper, if not, it’s worth the investment, the small bottles will last forever if you keep them closed up well. I get it, I like my basses shiny, might as well keep it pretty, your bass, your rules. A big scratch like that would bug the hell out me, but it’s eminently fixable.
 
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