Can I Over Buff my Guitar Finish?

[PAcaster]

Let me explain. I am building a guitar and finishing with an acrylic lacquer finish.

I wet sanded the body with paper in the following grit progression: 500, 800, 1000, 1500 and 2500. After this progression, the finish was very smooth, but with microscopic scratches that I could only see in certain angles of reflected light.

So using a Ryobi 6" orbital buffer, I gave the back of the guitar a shot of Meguiar's Ultimte compound. This is supposed to be their version of a hybrid polishing compound. After a good once over, the finish now seems almost "marred". I have some areas that are clear (to the sparkle below) and some that have almost a ghostly amoeba cloud. To the touch, the surface feels completely smooth, but this "stain" remains.

I gave it a shot of Meguiar's Swirl Remover 2.0 and then Meguiar's Show Car Glaze, and while about half of the back looks great, the ghostly amoeba "stain" remains.

Keep in mind this is my first build, and I may be doing this all wrong. Any suggestions? Thanks,

[Shepherd]

Sounds like you overheated the finish but hard to know without pics. You have to be careful to keep the buffer moving or it starts to melt the finish. You might be able to sand and buff it out but remember that your clear coat might be getting thin. Another option is to try some rubbing compound on the problem areas and see if that helps.

[PAcaster]

Originally Posted by Shepherd

Sounds like you overheated the finish but hard to know without pics. You have to be careful to keep the buffer moving or it starts to melt the finish. You might be able to sand and buff it out but remember that your clear coat might be getting thin. Another option is to try some rubbing compound on the problem areas and see if that helps.

Thanks, I'm trying to get some pictures that show the finish. In the meantime, would you happen to know if rubbing compound is more or less abrasive than 2500 grit wet paper?

[PAcaster]

Originally Posted by Shepherd

Sounds like you overheated the finish but hard to know without pics. You have to be careful to keep the buffer moving or it starts to melt the finish. You might be able to sand and buff it out but remember that your clear coat might be getting thin. Another option is to try some rubbing compound on the problem areas and see if that helps.

Okay, so I managed to get some pictures of the staining. Keep in mind this is a black sparkle finish guitar. The lighting isn't great, and I am only using my phone, but you should get the idea. Thanks!

[walsty]

I am not the expert a lot of the guys around here are but that white-ish looks like you could have water in the finish. You may need to shoot the area with blush eraser.

[Thinlineggman]

How thick is your clear coat? Looks kinda like you burnt through it...

[PAcaster]

Originally Posted by Thinlineggman

How thick is your clear coat? Looks kinda like you burnt through it...

The clear is actually very thick. I followed Buckocaster's method of making a sparkle guitar, and used a flour sifter to drop the flake on a tack coat of clear. I then used countless cans of acrylic lacquer to raise the surface. This staining is practically invisible when looking straight down on the body of the guitar. It only becomes apparent when you tilt it and look at it from varying angles.

[PAcaster]

Originally Posted by walsty

I am not the expert a lot of the guys around here are but that white-ish looks like you could have water in the finish. You may need to shoot the area with blush eraser.

I actually never heard of blush eraser before your mention. After doing some research, it seems like a great tool! I wish I knew about this much sooner in my build!

[bullfrogblues]

It almost looks like you didn't sand it perfectly level and there are spots that didn't get sanded at all. Hard to tell with those pics.

[Keyser Soze]

Originally Posted by bullfrogblues

It almost looks like you didn't sand it perfectly level and there are spots that didn't get sanded at all. Hard to tell with those pics.

I agree. The hazy areas are low spots where the higher grit papers were not making good contact, so did not remove the larger abrasions. When you buff you are effectively polishing two areas with different surface textures - they'll never buff out the same.

The solution is to shoot a few more layers of clear, then level sand.

[PAcaster]

Originally Posted by Keyser Soze

I agree. The hazy areas are low spots where the higher grit papers were not making good contact, so did not remove the larger abrasions. When you buff you are effectively polishing two areas with different surface textures - they'll never buff out the same.

The solution is to shoot a few more layers of clear, then level sand.

Thanks Bullfrog and Keyser (there is no Keyser Soze). Regardless of the reason, I sadly figured I would be shooting more clear, and then sanding again. I'll be happy to get this done.

Check out www.hellecaster.com for my build blog of this guitar....

[Shepherd]

Originally Posted by PAcaster

Thanks, I'm trying to get some pictures that show the finish. In the meantime, would you happen to know if rubbing compound is more or less abrasive than 2500 grit wet paper?

I use 3M Perfect-It Rubbing Compound and it removes scratches finer than 1200 grit so it's coarser than 2500. I refinished this one and sanded to 1200 followed by a light coat of blush eraser followed by the rubbing compound and then 3M™ Perfect-It Machine Polish and there are no scratches. I still think that looks like the finish was softened or was still too soft to buff. You could try a light coat of blush eraser to re flow the finish and remove some of the scratches.

[bullfrogblues]

The first wet or dry sand you perform in your sanding/polishing schedule should get rid of all shiny spots on the guitar body. If you look across the body in a glare type view, you should not see any shiny spots. If you do, you haven't sanded enough. It needs to be perfectly flat before you proceed to the next grit. And you should always use some sort of block to make the surface flat.
good luck.

[Jack FFR1846]

Couple questions....

Did you use a sanding sponge when doing the sanding?

How long did you wait once finished with spraying before sanding? Before buffing?