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Machine Polishing Need help with Machine polishing

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Old 08-02-2018, 12:26 PM   #11
percymon
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They look to have been caused by the service garage putting dirty wing protectors on, or putting wing protectors onto a dirty wet car, then scratching the paint with movement or during fitting/removal.

Those paint protection blankets are more trouble than they are worth
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Old 08-02-2018, 12:44 PM   #12
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That's a good shout, hence they're in the same place on both sides. Annoying as the car has quite new front wings too apparently after hitting a deer
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Old 12-02-2018, 11:53 AM   #13
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Can somebody explain why sanding out the scratches will remove less paint than compounding them out? Surely, to remove them entirely you just need to level off the paint, which will require the same amount of paint to be removed regardless of which way you do it?

Or is it just that you're more likely to remove too much with compounding for some reason?

I'd have thought you were less likely to do this though, as compounding tends to remove material at a slower rate than sanding...?

Unless there's another factor that I'm missing?

TIA
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Old 12-02-2018, 02:05 PM   #14
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Originally Posted by MBRuss View Post
Can somebody explain why sanding out the scratches will remove less paint than compounding them out? Surely, to remove them entirely you just need to level off the paint, which will require the same amount of paint to be removed regardless of which way you do it?

Or is it just that you're more likely to remove too much with compounding for some reason?

I'd have thought you were less likely to do this though, as compounding tends to remove material at a slower rate than sanding...?

Unless there's another factor that I'm missing?

TIA
Because you can isolate the scratches more with wet sanding that you can with a da. Even a 3in pad on a 5mm throw machine will remove more clearcoat from the surrounding areas than a small piece of sandpaper. You can attack the scratches pretty much alone with sandpaper. All depends on how careful you are.
You're right in that whether you compound or wet sand, you still need to remove the same amount of paint to level the scratches. You can just ensure the size of area you do this to is less with sandpaper.
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Old 12-02-2018, 02:06 PM   #15
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Top man, thanks. I thought there would be a simple answer!
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Old 12-02-2018, 04:18 PM   #16
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You need to take readings to see what you've got to play with. Wet sanding should be a last resort. It needs compounding so do a test spot and see. If you've got high readings then wet sand. The trouble you have is with the marks going right up to the edge.
Compounding has been proven on here previously to have the potential to remove more CC than wet sanding! I'd say measure and then which ever route you choose to take, proceed with caution!
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Old 05-03-2018, 10:43 PM   #17
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Before you start wet sanding, do the scratches disappear when wet? If so, a good compound will get most of them out. If you can still see the scratches when wet, I doubt you’ll get them out completely without risky wet sanding. Having said that, even polished scratches are less obvious than unpolished ones.


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Old 11-03-2018, 02:57 AM   #18
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If you can catch your nail in the scratches, chances are, they're too deep to remove FULLY. Problem with going at it with a machine is heat and its on an edge. Problem with wet sanding is...you're on an edge
either way you're limited to what you can do and chasing perfection may not be possible. I would try a 3" pad to finesse the area, see what results you get, if they're not the results your after, as Chongo said, try a few light passes with some 2000-2500 grit, polish back up and be happy with the results at that point. Last thing you want is a resprayed panel!
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Old 11-03-2018, 07:33 AM   #19
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I've just bought an Audi A5 and it has deep scratches on the tops of the front wings. I'm wondering if anyone thinks these will be masked/reduced by polishing alone, or if I should wet sand it a bit? Any advice appreciated, I've not been on this forum for a while and my already limited detailing knowledge I'm sure I've forgotten most of!

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Stupid question time - did you buy it from a garage and if so, why not get them to sort it ?
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Old 23-03-2018, 10:43 AM   #20
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No, I bought it privately. The guy said they were very recent resprays after hitting a deer, so really annoying that the whole front end has been treated so badly!
I've been so busy I've only given the car a basic wash once in the 6 weeks or so I've had it (Shame on me) let alone polish anything, but I've definitely decided to stay away from wet & dry! Masking these scratches even 50% would be great, I think they are too deep to lose completely.

I will of course update this thread with how I get on
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