Joined
·
2,576 Posts
I've found it surprising what improvement can be made to quite bad scuffs, especially by wet-sanding with 2000 grit and 3000 grit Abralon (foam/nylon fabric abrasive pads) before the polishing stage. If the scratches snag a fingernail, then in my opinion sanding is needed - otherwise you'll just polish the grooves rather than smoothing them. If the scratches are down to the primer or plastic, I fill them with touch-up paint before wet sanding (obvious but just thought I'd clarify).
It does take careful judgement and practice to know how much sanding you can do, and Tommy was right to recommend against it until you've had chance to practice.
But it is certainly helpful in some cases, particularly to remove any material (other paint, plastic, etc) that's been transferred onto the surface. If you do a very little bit of wet sanding (soapy water) and then wipe the surface dry, you can see the untouched shiny areas and the areas that are now dulled. Remaining scratches will be more obvious, so you can see your progress.
I know there is a risk of messing it up. But I think the way to look at it is that it needs a respray to be perfect again, so as long as you make a noticeable improvement, you have succeeded.
I use a DAS6 as well. It's essential to use a silicone-free polishing compound so that you can see when you've achieved a genuine shine (rather than a silicone shine that will soon fade in a few days and leave a dull patch). My favourite is Chemical Guys V36 (from the US). It's a diminishing abrasives compound, easy to clean up and finishes well from as low as 1500 grit, though much faster from 3000. A European favourite of mine is Mirka T10, though it is a tad coarser and needs Mirka F05 to finish (the V36 is capable of replacing both).
Maybe the reason I wet-sand first is because I have a 'tame' compound and a DA machine, which I know doesn't remove much material (just puts a shine on what is there). That's safer than using a rotary machine with a coarser compound (to get out the scratches) and potentially burning through the paint where you weren't even trying to polish, which is what used to happen in some of my early disasters... I would never use a rotary for any detail work now - only perhaps for a van roof or some other big area. DAs are wonderfully controllable in comparison.
-Alex
It does take careful judgement and practice to know how much sanding you can do, and Tommy was right to recommend against it until you've had chance to practice.
But it is certainly helpful in some cases, particularly to remove any material (other paint, plastic, etc) that's been transferred onto the surface. If you do a very little bit of wet sanding (soapy water) and then wipe the surface dry, you can see the untouched shiny areas and the areas that are now dulled. Remaining scratches will be more obvious, so you can see your progress.
I know there is a risk of messing it up. But I think the way to look at it is that it needs a respray to be perfect again, so as long as you make a noticeable improvement, you have succeeded.
I use a DAS6 as well. It's essential to use a silicone-free polishing compound so that you can see when you've achieved a genuine shine (rather than a silicone shine that will soon fade in a few days and leave a dull patch). My favourite is Chemical Guys V36 (from the US). It's a diminishing abrasives compound, easy to clean up and finishes well from as low as 1500 grit, though much faster from 3000. A European favourite of mine is Mirka T10, though it is a tad coarser and needs Mirka F05 to finish (the V36 is capable of replacing both).
Maybe the reason I wet-sand first is because I have a 'tame' compound and a DA machine, which I know doesn't remove much material (just puts a shine on what is there). That's safer than using a rotary machine with a coarser compound (to get out the scratches) and potentially burning through the paint where you weren't even trying to polish, which is what used to happen in some of my early disasters... I would never use a rotary for any detail work now - only perhaps for a van roof or some other big area. DAs are wonderfully controllable in comparison.
-Alex
