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View Full Version : Can You Use the PC to Polish-out #2000 Grit Sanding Marks?



JJ1
Jan 21st, 2007, 04:47 PM
Can You Use the PC to Polish-out #2000 Grit Sanding Marks? (http://www.meguiarsonline.com/forums/showthread.php?t=18202)

Fixing a chip and sanded down the touch up paint with 2000 grit. Was thinking of using new ScratchX on a DA to polish it out. Would ScratchX do the job on a 2000 sand job, or should I use something else?

frustrateddetailer
Jan 21st, 2007, 05:35 PM
Fixing a chip and sanded down the touch up paint with 2000 grit. Was thinking of using new ScratchX on a DA to polish it out. Would ScratchX do the job on a 2000 sand job, or should I use something else?

it will lessen the sanding marks but it will not take those scratches out completely. i think medium cut cleaner will do the job with a rotary. . :D:D:D

Zet
Jan 22nd, 2007, 06:18 AM
It would probably work better by hand, this is because you are able to apply more pressure in a concentrated area working by hand, compared to the PC. But it would probably take lots of applications ;)

Mike Phillips
Jan 22nd, 2007, 07:28 AM
It would probably work better by hand, this is because you are able to apply more pressure in a concentrated area working by hand, compared to the PC. But it would probably take lots of applications ;)

We've read that somewhere before...

Mike Phillips
Jan 22nd, 2007, 08:26 AM
Fixing a chip and sanded down the touch up paint with 2000 grit. Was thinking of using new ScratchX on a DA to polish it out. Would ScratchX do the job on a 2000 sand job, or should I use something else?

Probably not. That said,

"You never know what you can do until you try"

It really depends on how hard or how soft the paint is. In most cases you can easily remove the sanding marks out of the touch-up paint because compared to the surrounding factory paint it will be soft.

In the world, in most cases,

"Modern clear coats are typically harder than traditional single stage paints"


What this means to you when you go out into your garage to work on your car is that you won't be able to get the sanding marks out of the clear coat paint surrounding the touch-up paint using a tool that oscillates and rotates, but under pressure quits rotating.

You could remove the sanding marks using a rotary buffer but in most cases the rotary buffer generates enough heat and power that while it's removing the sanding marks surrounding the touch-up paint, it will effectively remove the touch-up paint because the touch-up paint is softer and will not hold up to the power of the rotary buffer over the time required to remove the sanding marks.

Complicated huh?

A true artist can do it, but it requires a lot of time, you have to let the touch-up paint harden for at least a week or so before starting the sanding and buffing process and if you're paying someone to do this, and they apply the touch-up paint, that would mean two visits to your car.

If the person is a true professional they're probably going to charge more than the average person is going to want to pay to have an area the size of a small chip work-on, on their car, (the small picture), especially considering most people don't like to pay what it costs to have a true professional work on the entire car, (the big picture).

As Zet stated, you would probably be more effective using your hand because you can exert more force with your 4 fingers pushing down on an applicator pad than you can with a dual action polisher because all of your downward force is exerted and spread out and then diminished over the entire surface of the buffing pad.


After applying a paint cleaner by hand to remove swirls and scratches to a car with a red single stage paint job and then turning the applicator over you can see that red pigmented paint accumulated the most where your 4 fingertips pressed down on the applicator pad. You get these same types of results when you're working on a clear coat finish by hand, (with a paint cleaner), except you can't see the accumulation of removed paint because it's clear.

http://archive.meguiarsonline.com/forums/photopost/data/649/FingerPressurePoints.jpg



Make sense?


Plus by hand you can control more precisely where you're applying the force. We've removed #2000 grit sanding marks by hand before, and it can be done, but again, how hard or easy it will be will completely depend on how hard the paint is surrounding the touch-up paint and your personal ability and technique coupled with persistence and perspiration.

When it comes to touch-up paint, especially rock chip repair, there is no quick and easy way to properly do job with the expectations of great, and even just good results.



Hope this helps...

Mike Phillips
Jan 22nd, 2007, 08:29 AM
Moving to Hot Topics (http://www.meguiarsonline.com/forums/forumdisplay.php?f=80) as this question comes up often enough to make it a "Hot Topic"

:D :D :D

yakky
Jan 22nd, 2007, 03:48 PM
You can use a PC to Polish down to bare metal. A rotary is faster at removing sanding marks, but by no means is a PC ineffective. I've used #84 on a red pad and taken out 2000 marks on a hood. It took 3-4 passes, I was being lazy and didn't want to dig out the rotary.

Mike Phillips
Jan 22nd, 2007, 03:53 PM
You can use a PC to Polish down to bare metal. A rotary is faster at removing sanding marks, but by no means is a PC ineffective. I've used #84 on a red pad and taken out 2000 marks on a hood. It took 3-4 passes, I was being lazy and didn't want to dig out the rotary.


That's only half the answer, this guy is working on top of touch-up paint, this creates a whole set of new issues that we outlined in our response.

We also don't recommend using our cutting pad with our compound on this forum as it leaves the paint looking scoured and then people get upset because they think the paint is going to look good when they're done.

So we don't want our members recommending procedures that cause the average enthusiast problems. The reason for this is Meguiar's will be held accountable, and you won't.

Does that make sense?

yakky
Jan 22nd, 2007, 05:52 PM
I understand your point. However its seems like the consensus is that a PC can't be used for serious correction work. It can, and IMO is much more safe than a rotary for a newbie. I can't imagine spending hours with scratchX when it could be done faster. I'll abide by your posting but that doesn't mean I'm not tempted to bring this to PM's :D

Mike Phillips
Jan 22nd, 2007, 06:00 PM
People can do what they want, but because of liability, accountability and responsibility, we don't recommend procedures that we can't back up with a high level of certainty that the average person can perform successfully when they walk out into their garage.

At the same time we understand that many of our forum members are experienced and talented enough to successfully tackle more difficult procedures. It's a balancing act.

Thanks for understanding.

JJ1
Jan 22nd, 2007, 07:00 PM
Hope this helps... (but it probably doesn't)

It helped and made a lot sense! Thanks!

Mike Phillips
Jan 23rd, 2007, 08:13 AM
It helped and made a lot sense! Thanks!



Good.

Appying touch-up paint and then making it look good, (that's 2 things, not just 1 thing), will always be a difficult procedure.

Best of luck to you!

JUtah
Apr 15th, 2007, 09:14 PM
Hey all... new to the forum, and I appoligize if this is in the wrong place but my search turned about about half a million returns, none of which seemed to apply... so here goes.

Had a friend who is a very skilled artist paint my motorcycle for me. He did a phenominal job at it but ran into problems with dust getting in the tank before the clear coat dried (He used HOK Paint and clear). He's not a proffesional painter, and was painting in his garage.

So... he sanded the tank with 1000 grit, then 2000 grit, then used one of the Meguires cutting compounds with a foam wheel to buff it out. The tank doesn't have that same gloss and high reflectivity as the areas that he didn't have to do this to and I am trying to figure out how to fix it. (If I look closely at certain angles I can still see the sanding marks.

Keep in mind I'm new to this whole paint prep/detailing deal so please be thorough in your explanations...

Thanks in advance,
Rich

Mike Phillips
Apr 15th, 2007, 10:02 PM
The tank doesn't have that same gloss and high reflectivity as the areas that he didn't have to do this to and I am trying to figure out how to fix it. (If I look closely at certain angles I can still see the sanding marks.



First, the sanding marks need to be removed using a cutting pad and a compound.

Second, the above process is just the first step, after an aggressive compound and a cutting pad you, (or he), needs to follow this with one or two more less aggressive products and pads, the better you want it to look the more you do.

Using just a compound and a cutting pad will leave the finish looking swirled, scoured and dull depending upon the light.