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      06-06-2017, 10:57 PM   #1
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Difficulty Compounding wetsand marks

Hi all, looking for some advice.

I found a long scratch on my cars hood, not very deep at all, but noticeable and ugly.

I wetsanded the mark down with 2000 grit which got rid of it.

Then used a DAS6-PRO, foam cutting pad and Menzerna 400 to compound the dull marks away and shine it up in prep for finishing compounds etc, this worked well however, its super shiny even with 400, however getting down close you can still see the wet sand cross hatching.

I then purchased 3000 grit and rubbed it down.

Then went over it a few more times and possibly improved it a bit.

Then purchased a microfiber cutting pad and used the 400 compound again, but its still there.

What are your opinions?

Should i leave it alone and call it a day, its impossible to see unless your head is less than a foot away, or should i just keep going?

The pads and compound dont seem to be cutting much away at all.

Here is what it looks like now
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Last edited by EB89; 06-07-2017 at 09:21 PM.
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      06-07-2017, 09:45 AM   #2
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I am really hopeful that you meant 2000 grit and 3000 grit?

But looking at those scratches, it does not appear to be the case.

You have used way too severe of sand paper for automotive finishing applications. The correct approach would have been to use something between 1000-3000 grit to remove a clear coat scratch.

2000-3000 grit paper leaves fine enough sanding marks that can easily be removed by machine compounding and polishing.

You're quite lucky you did not strike through your clear coat if you did in fact use 200 and 300 grit paper. You will need to continue sanding (and hoping you have enough clear coat left), working your way up to 2000-3000 grit before compounding.

-Zach
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      06-07-2017, 10:01 AM   #3
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Quote:
Originally Posted by Detailed Image View Post
I am really hopeful that you meant 2000 grit and 3000 grit?

But looking at those scratches, it does not appear to be the case.

You have used way too severe of sand paper for automotive finishing applications. The correct approach would have been to use something between 1000-3000 grit to remove a clear coat scratch.

2000-3000 grit paper leaves fine enough sanding marks that can easily be removed by machine compounding and polishing.

You're quite lucky you did not strike through your clear coat if you did in fact use 200 and 300 grit paper. You will need to continue sanding (and hoping you have enough clear coat left), working your way up to 2000-3000 grit before compounding.

-Zach
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      06-07-2017, 10:15 AM   #4
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I did a similar repair this weekend.

I used 3000grit wet sandpaper followed by megs 105 on an orange pad, megs 205 on a white pad. Even with 3000 grit sandpaper it took a while to get it back to that factory shine.

If you truly used 200 and 300 grit sandpaper then you need to get some 1000, 2000, and 3000 and then go in that order until all the deep marks are out, HOWEVER, your clear coat will be so thin or possibly non-existent after this that it might just be better to leave it as is. I would be very surprised if you managed to not break through your clear coat with 200 grit.
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      06-07-2017, 04:03 PM   #5
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I used 3000grit wet sandpaper followed by megs 105 on an orange pad, megs 205 on a white pad. Even with 3000 grit sandpaper it took a while to get it back to that factory shine.
Microfiber or wool cutting pads would have sped up your progress considerably.

Keep them in mind for future projects...
Microfiber Cutting Pad
Wool Cutting Pad
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      06-07-2017, 04:13 PM   #6
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Quote:
Originally Posted by Detailed Image View Post
Microfiber or wool cutting pads would have sped up your progress considerably.

Keep them in mind for future projects...
Microfiber Cutting Pad
Wool Cutting Pad
Thanks for the tip. I rarely do these kinds of repairs (only ever got out the sandpaper twice in my life) so that's why I stuck to the orange pad that I already had.

If I need to do more of this in the future I will scoop up one of those two products!
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      06-07-2017, 04:22 PM   #7
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200 grift, 300 grit sand paper on car paint?

You gotta be joking with us, right?

Stop what you are doing, and fowllow Zach's advice. Personally at this point I don't think you should be doing any paint correcting yourself, but rather get a professional.

You do know you will have to paint your hood.
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      06-07-2017, 09:07 PM   #8
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Quote:
Originally Posted by Detailed Image View Post
I am really hopeful that you meant 2000 grit and 3000 grit?

But looking at those scratches, it does not appear to be the case.

You have used way too severe of sand paper for automotive finishing applications. The correct approach would have been to use something between 1000-3000 grit to remove a clear coat scratch.

2000-3000 grit paper leaves fine enough sanding marks that can easily be removed by machine compounding and polishing.

You're quite lucky you did not strike through your clear coat if you did in fact use 200 and 300 grit paper. You will need to continue sanding (and hoping you have enough clear coat left), working your way up to 2000-3000 grit before compounding.

-Zach
Ha yes 2000 and 3000

200 i would be down to bare metal
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      06-07-2017, 09:11 PM   #9
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Sorry folks, procedure was

- 2000 grit
- Menzerna 400 + LC Foam
- Inspect
- Menzerna 400 + LC Foam
- Inspect
- Menzerna 400 + LC Foam
- Inspect, looks good but can see the sanding marks
- 3000 grit
- Menzerna 400 + LC Foam
- inspect
- Menzerna 400 + LC Foam
- inspect
- Menzerna 400 + LC Microfibre
- inspect
-Menzerna 400 + LC Microfibre

I think i might order a Lake Country Purple Wool pad, im think the cutting is just not abrasive enough, im bareley removing any clear, the hood is shiny as hell right now, but those sand marks look dodgy.

Im fully aware a hood respray is a possibility, infact that is exactly why im using the hood, im thinking of getting a new hood anyway, but how often do you get to practice wet sanding on a panel and correcting it back to perfection, its good practice for me.
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      06-07-2017, 10:12 PM   #10
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Based on the straight line scratches, it appears you were sanding by hand.

It is common for small particles to become trapped beneath your sanding paper and the paint creating deeper scratches that we call tracers. This is usually a result of not using enough water, not cleaning the paint often enough, and not cleaning the paper out often enough.

I would start again with some 3000 grit paper and level these remaining tracers properly. I would not expect compound to level the amount of texture I see remaining in your photos.

Be sure to completely clean the paint prior to beginning the sanding, and be sure to continue to rinse the paint and paper frequently to ensure there are no particles that may gouge the paint while sanding. Use light pressure, too!

Good luck!

-Zach
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      06-07-2017, 11:19 PM   #11
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Quote:
Originally Posted by Detailed Image View Post
Based on the straight line scratches, it appears you were sanding by hand.

It is common for small particles to become trapped beneath your sanding paper and the paint creating deeper scratches that we call tracers. This is usually a result of not using enough water, not cleaning the paint often enough, and not cleaning the paper out often enough.

I would start again with some 3000 grit paper and level these remaining tracers properly. I would not expect compound to level the amount of texture I see remaining in your photos.

Be sure to completely clean the paint prior to beginning the sanding, and be sure to continue to rinse the paint and paper frequently to ensure there are no particles that may gouge the paint while sanding. Use light pressure, too!

Good luck!

-Zach
Thank you Zach, Yes it was a hand sanding job.

I washed, and clayed then use IPA over the spot before hand but im sure that the sanded off clear was getting trapped.

I might first try a wool pad before going back to sanding but thank you for the advice, much appreciated.

Also worth noting is the photo was taken after at the point of the third inspection, more work was done including 3000 after this photo was taken and its not that bad now, looks much better.
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