Black MB scratch

J

JSFM35X

Active member
A good freind of mine had a BBQ yesterday. Afterwards he showed me a scratch on the trunk lid of his wife's car. It was about 12 inches and I could not feel it with my nail so I figured this would be easy. Wrong.

I used my Rupes 3" machine. First I tried Rupes green with the green polish, then I tried m100 with Rupes green. Nothing. Then I moved to Rupes blue with m100 and that did give some cut but it took 4-5 cuts of many passes each to get it cut out. I tried light pressure with full throw on the pad. Heavy pressure and less throw.

What do I need to get these types of defects cut out. It took me close to an hour to get it cut out and then polished. All I ded was the trunk lid on a CLA.

Thanks.
 
Mercedes Benz has hard paint, so I would use a Makita 9227 with an extension and a 3" backing plate and pad, then a 5" backing plate and pad to finish the rest of the deck lid so it all matches..
Would take way less time and yield excellent results..
Dan F
 
Bump up to a micro pad and go slow, or sand with 3000 and then polish out. The sanding is actually easier on the paint versus the heat you are generating with the pad.
 
Isn't that a Rotary? If so I would be afraid of Swirls/ holograms.

Stokdgs said:
Mercedes Benz has hard paint, so I would use a Makita 9227 with an extension and a 3" backing plate and pad, then a 5" backing plate and pad to finish the rest of the deck lid so it all matches..
Would take way less time and yield excellent results..
Dan F
Click to expand...
 
I have a yellow and blue MF Rupes pad so I will try that next. Which polish would you suggest.

I am not skilled at wet sanding. I have tried it a few times, took a load of polishing to get it back shiney.

I am sure I just did not use the proper combo.

Mike lambert said:
Bump up to a micro pad and go slow, or sand with 3000 and then polish out. The sanding is actually easier on the paint versus the heat you are generating with the pad.
Click to expand...
 
Mike lambert said:
Bump up to a micro pad and go slow, or sand with 3000 and then polish out. The sanding is actually easier on the paint versus the heat you are generating with the pad.
Click to expand...

Wet Sanding with 3000 is what I would recommend also. Just go slow and keep periodic checks on your paint thickness to see how much is being removed. I know it can be a little scary when you start to sand paint - But like Mike said; the sanding is actually better because it doesn't produce heat and you can be very precise with what you are removing. I have never had any problems polishing out 3000 grit sanding marks even with a DA.
 
Yes, its a Rotary, and I never leave swirls or holograms, etc., and you can also do this if you want.
The secret - keep the pad flat on the surface, use a little spritz of something so it doesnt get dry, and completely finish out that spot so the product is about gone.
Your pad is able to do this just fine, I use the Lake Country Hydro Shred Cyan pads like this and they really work great and leave an excellent gloss and clarity.
Yes, the paint might be the ceramic paint Mercedes introduced at least a decade ago to make their paint more scratch resistant.
Menzerna worked with Mercedes at that same time to develop compounds that would be able to work with this new paint back then.
Good luck !
DanF
 
I always thought the reason for sanding was to level the paint down to the scratch without making the scratch deeper.

But ya.

FG400 + Cyan is pretty beastly on german clear.
 
Stokdgs said:
Yes, its a Rotary, and I never leave swirls or holograms, etc., and you can also do this if you want...
Click to expand...

I envy you Rotary-Meisters who can always finish out hologram-free! I've used rotaries on/off since the '70s and I still leave some holograms (on b/c paint) regularly enough that I simply retired both my rotaries a few years back. Now, no more DA/etc. follow-up to fix the holograms (which were a big inspection hassle; think I got 'em and then when the sunlight is *just right* I'd see a faint one...have to redo). Not sure if I'm saving all *that* much time during the correction, but knowing that I won't find some faint hologram later on is worth it to me. (Now I have a scad of wool pads/etc. and two rotaries just gathering dust, oughta sell 'em to one of you guys who still use 'em...)

JSFM35X- IMO the "can't feel with fingernail" is a pretty, uhm.... uncontrolled test. Again just *IMO*, but even RIDS less severe than that can lead to taking off a lot of clear and precipitating future problems. I'm seeing *SO* many vehicles these days with cc failure on the "commonly/frequently corrected" surfaces and I bet it'll get worse in the future.

wetsanding *can* be more gentle (paint-removal-wise) than aggressive compounding, and I do it when I think it's advisable, but *SO* many seemingly bright/careful/etc. people have done damage when they wetsanded that I've finally put it in the "if you have to ask about it, just don't do it" category. I'd certainly have an ETG on-hand before starting it. (OK, call me Mr. Conservative but I do think long-term and removing a few too many microns of clear now can cause failure five years down the road).

I too struggle with time-efficient work like that and I don't even have the Rupes (bet it's much better than my 3" Griot's Pneumatic). I do OK with M101 (finally tried it recently and it did cut Audi clear a *LOT* faster than M105 v1.0) using a MF Cutting Disk. As you're already using M100 I suspect the MF Cutting Disk would be a worthwhile upgrade.

Then just take the time and do what you're doing. IMO you didn't do all *that* many more passes/take all that much more time than I sometimes do on the Audis. I know that plenty of people on the internet do stuff in the blink of an eye and never have any problems, but in *my* version of real life some stuff takes a lot of time and effort and sometimes the best intentions come back to bite.
 
As I was doing this little trunk lid, all I kept thing was if I was doing this whole car it would take me forever.

I even left out the part where I was not 100% satisfied with the end result under the rupes light. But my friend thought it was perfect and wanted to go home! So I left it as it was.


Accumulator said:
I envy you Rotary-Meisters who can always finish out hologram-free! I've used rotaries on/off since the '70s and I still leave some holograms (on b/c paint) regularly enough that I simply retired both my rotaries a few years back. Now, no more DA/etc. follow-up to fix the holograms (which were a big inspection hassle; think I got 'em and then when the sunlight is *just right* I'd see a faint one...have to redo). Not sure if I'm saving all *that* much time during the correction, but knowing that I won't find some faint hologram later on is worth it to me. (Now I have a scad of wool pads/etc. and two rotaries just gathering dust, oughta sell 'em to one of you guys who still use 'em...)

JSFM35X- IMO the "can't feel with fingernail" is a pretty, uhm.... uncontrolled test. Again just *IMO*, but even RIDS less severe than that can lead to taking off a lot of clear and precipitating future problems. I'm seeing *SO* many vehicles these days with cc failure on the "commonly/frequently corrected" surfaces and I bet it'll get worse in the future.

wetsanding *can* be more gentle (paint-removal-wise) than aggressive compounding, and I do it when I think it's advisable, but *SO* many seemingly bright/careful/etc. people have done damage when they wetsanded that I've finally put it in the "if you have to ask about it, just don't do it" category. I'd certainly have an ETG on-hand before starting it. (OK, call me Mr. Conservative but I do think long-term and removing a few too many microns of clear now can cause failure five years down the road).

I too struggle with time-efficient work like that and I don't even have the Rupes (bet it's much better than my 3" Griot's Pneumatic). I do OK with M101 (finally tried it recently and it did cut Audi clear a *LOT* faster than M105 v1.0) using a MF Cutting Disk. As you're already using M100 I suspect the MF Cutting Disk would be a worthwhile upgrade.

Then just take the time and do what you're doing. IMO you didn't do all *that* many more passes/take all that much more time than I sometimes do on the Audis. I know that plenty of people on the internet do stuff in the blink of an eye and never have any problems, but in *my* version of real life some stuff takes a lot of time and effort and sometimes the best intentions come back to bite.
Click to expand...
 
JSFM35X said:
.. I was not 100% satisfied with the end result under the rupes light. But my friend thought it was perfect and wanted to go home! So I left it as it was.
Click to expand...

That's plenty good enough in my book; why thin the clear more if the owner is satisfied?
 
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