MT300 and paint correction on Mercedes GL450

[AlexSD]

Hello,

I am a complete novice to auto detail and hope to get some advise from more experienced people on this forum. My wife drives a black Mercedes GL450 that has tons of swirl marks and general paint scratches, most of which are not very deep. I am using her car as my first training project to learn how to detail using DA polisher. I fully realize that Mercedes' clear coat is super hard and may present a challenge to even an experienced detailer, not to mention a roukie like myself. Unfortunately, the is the only car I can practice my skills on right now.

I took Meguiar's Detailing 101 class a couple of weeks ago and got inspired by Mike's hands on presentation of the new MT300. I received my MT300 yesterday and spent most of the day today working on the wife's car. I washed the car using the two bucket method and clayed it with blue (mild) Meguiar's auto clay.

Along with MT300 I am using 5-inch backing plate and 5 inch cutting (burgundy) disk to apply Ultimate Compound. Once I go over with the cutting disk I finish the process with Black Wax (G6207) in combination with dark gray 5-in polishing disk. Throghout the day I played with speed settings on the MT300 going from 4800 to 5800 and found that I needed to keep speed around 6000+ to make any dent in the clear coat.

A couple of questions to the folks familiar with DA polishers:

1. I takes me about 45 minutes to cut one panel using Ultimate Compound running at 6000+ speed. Even after 45 minutes I can still see some scratches in clear coat. About 95% of swirl marks are gone but there may be some deeper scratches that can still be visible under florescent light source. I am very careful not to burn through the paint as constantly feel the temperature of the surface with my hand since I am running DA at a pretty high speed. Is this normal to still see scratches after 45 minutes of working with UC?

2. How often do I need to refresh the disk with UC? Is it necessary to keep the cutting disk constantly 'moist' with the polishing chemical? Mine gets dry pretty fast probably due to high speed and higher temperature.

Any feedback would be greatly appreciated.

Thank you,
Alex

[The Guz]

Re: MT300 and paint correction on Mercedes GL450

Well as always the best approach is to start with a test spot with the least aggressive combination. Let the paint tell you what it likes. That's the first tip for someone always starting out.

Have you thought about using ultimate polish after using ultimate compound instead of black wax. There is nothing wrong with what you used but the polish will give you more gloss than a cleaner wax (aka an all in one product). Just another idea for you to play with. Of course you would use ultimate polish with the yellow foam polishing disc.

It will take a little time to get your technique down a little since you are new to DA polishing. You should only need to use a speed of about 5800 OPM's. You may want to shrink your work area and slow your arm movement. Also having the right amount of pressure when using a DA is important.

A couple of questions to the folks familiar with DA polishers:

1. I takes me about 45 minutes to cut one panel using Ultimate Compound running at 6000+ speed. Even after 45 minutes I can still see some scratches in clear coat. About 95% of swirl marks are gone but there may be some deeper scratches that can still be visible under florescent light source. I am very careful not to burn through the paint as constantly feel the temperature of the surface with my hand since I am running DA at a pretty high speed. Is this normal to still see scratches after 45 minutes of working with UC?

A speed of 5800 OPM's should be all you need. You may need to use more than one pass to get the area swirl free. But it sounds like you are seeing what is referred to as RIDS (random isolated deeper scratches). These of course would require a lot more work and a more aggressive method. You may have to live with those and accept that you have the surface 90-95% free of defects. There is some good info in this thread about RIDS

http://www.autogeekonline.net/forum/hot-topics-frequently-asked-questions/24045-rids-definition-rids-story-behind-term.html

2. How often do I need to refresh the disk with UC? Is it necessary to keep the cutting disk constantly 'moist' with the polishing chemical? Mine gets dry pretty fast probably due to high speed and higher temperature.

I fully prime/season my pads with a compound and polish. With the new pads 3 pea sized drops works best. You will have to add more product after you have made a few passes. You should also clean your pads after every panel. A properly cleaned pad will net you better results.

Check out this video. Kevin Brown has some very good info in it. Around 12:15 is where he shows how to prime/season the pad.

[AlexSD]

Re: MT300 and paint correction on Mercedes GL450

Thank you "The Guz" for good insight. I really like your suggestion on using Polish as an intermediary step before applying Black Wax. According to Mike Stoops, the Black Wax has a lot of polishing components but I also wonder if adding additional step would give the car extra depth and metallic glow. I've gone out and got a bottle of Meguiar's Polisher and plan on giving it a shot tomorrow.

Also, thank you so much for posting the video as I learned a lot of useful information.

I have several other questions that I am hoping to get answers to:

1. Mercedes GL450 is a BIG car and there is no way I could finish it all in one day (at least not with my present skill level). It took me good 8 hours to wash the car, clay it, and do paint correction + wax on the hood plus all four panels on the passenger side. I now need to go over its roof, rear gate and driver side. I was not able to get to it today and the car has been sitting in the garage. I have noticed light dust already accumulated on the roof and hood. What is the best way to clean the dust off prior to continuing paint correction? Should I just wipe it off with UDS?

2. While doing paint correction on side panels using red disk and UC, I noticed sort of a rainbow stains appearing on top of clear coat. Once stopped, those rainbow looking stains seemed to disappear. They remind me of motor oil stains on top of water. Would anyone have any idea what it might be? Could it be some residual chemical on top of the paint from the claying step?

3. Tape or not to tape chrome trim and headlights? What is everyone's general opinion?

4. I need to restore and detail headlights. As a general rule does it make sense to detail the car first and then work on the headlights or the vise versa? Would applying the blue tape to the hood and surrounding area take the wax off with tape removal?

5. What is the best practice on working with plastic bumpers? Do I still go over with red disk and UC but maybe at a slower speed?

6. GL450 has a funky moonroof as part of the roof panel. It's toward the back of the vehicle. The panel is notorious for peeling off -- I think this is some kind of a tinted fiberglass with a clear coat on top of it. The clear coat gets old and starts peeling off making the roof look horrible. I am thinking that the panel is not much different from a headlight and contemplating of using new Meguiars 2 step headlight restoration kit (G2000) on it. Would anyone have any opinion on this option? I am sure that I am not the only Mercedes owner battling this issue with the moonroof.

Thank you for your feedback,
Alex

[The Guz]

Re: MT300 and paint correction on Mercedes GL450

No problem. I actually should have been a little more clear. What I meant is replacing black wax with ultimate polish and use another wax product (for example Gold Class, NXT, Ultimate Wax). Black wax is a cleaner wax and yes it offers more poliihing oils than white wax. But since it is a cleaner wax, it will remove the polishing oils from ultimate polish. A dedicated product for a specific purpose will net you better results.

Regarding your questions:

1. A quick detailer is fine to remove light dust. If it's heavy dust then I would either use a rinseless wash or waterless wash. If you don't have access to those then washing it. Really depends on how much dust is on the surface.

2. Not really sure what you are seeing here. Photos help.

3. It's pretty common to tape any trim to avoid any compound, polish or wax residue from getting on them. It makes less work for you by taping it off. Just be sure to use a good tape that does not leave a lot of adhesive residue behind.

4. It depends on how sever the oxidation is on the headlights. You may be able to get away by compounding and polishing them. If not then sanding may be needed.

5. Try a test spot and see how aggressive you need to go. Perhaps all you need is a polish.

6. Photos are always helpful. I would be hesitant to sand anything.

[AlexSD]

Re: MT300 and paint correction on Mercedes GL450

Thank you again, Michael for your advise. I have a bottle of NXT and a bottle of Ultimate Wax and will give them a shot. Now, if I wanted to re-do the sections which were done previously with Black Wax what would be the best method to remove it from the surface? Do I just wash the car with Dawn? Or may I also use something like D114 to wipe the car clean?

I will take a picture of the moonroof to illustrate the problem there.

Another question -- how do professionals handle separate panels? Do they finish one panel at a time -- i.e. apply all three steps to a single panel and move on to the next one?

Last questions -- I am thinking about getting 3in backing plate for my MT300 as GL350 has many tight spots and ridges where 5in is just to big to reach into. I found the 3in backing plate but couldn't not find 3in pads from Meguiars. All I saw was 4 inch foam pads. Do 3 inch foam pads exist or do I go with 4in to give a bit of a number around the backing plate?

Thank you.
Alex

[Michael Stoops]

Re: MT300 and paint correction on Mercedes GL450

Alex, when working with harder clears such as yours appears to be (and by the way, not all Mercedes clear is hard - some are actually very soft and haze easily) your technique becomes really critical. We've worked on some very hard clears with the MT300 and the burgundy foam cutting disc and it tends to be a fantastic match. Make sure that you're keeping your work area small - roughly the size of a microfiber towel, if not a bit smaller even. It is very important to move the tool slowly across the paint to give everything time to work against the defects. Also, make sure you're using some pressure against the paint. You don't want to stand on the tool, but you do need some moderate (at least) pressure to help things along. Now, if the paint is hard enough, and the defects severe enough, you may have the perfect candidate for our Microfiber System. The microfiber discs alone will give a big boost in cutting ability, and coupled with M100 instead of UC will boost that cut even more.

Just keep in mind that just because your wife's car has very hard clear and really nasty defects that won't go away quickly, causing you to get more aggressive with your process, that does not mean you need to use the same aggressive process when you get around to working on your own car.

[AlexSD]

Re: MT300 and paint correction on Mercedes GL450

Thank you for the answers and suggestions, Michael.

A quick question -- if I were to re-do the car with UC, Ultimate Polisher and NXT, what is the best way to remove the Black Wax that I'd already applied to half of the vehicle? Should I wash the car with dishwasher soap? Can I just wipe it off with Detailer's Spray? Can I use a consumer version of D114 (I guess it has wax in it already mixed in so not really sure what good it would do to remove the Black Wax)? Should I wipe it with 10% IPA mixed with distilled water?

Thank you in advance for your advice. By the way, I was able to pick up 3 inch backing plate for my new MT300 and a bunch of pads from a local detail supply store down here in San Diego. Jane (one of the store owners) had all kinds of nice words to say about you .

Thank you again, Michael.

Alex from San Diego

[The Guz]

Re: MT300 and paint correction on Mercedes GL450

You can use IPA to strip it or a light polish with ultimate polish and polishing pad. Since you already did those area's, I would just apply NXT on top of it and proceed with ultimate polish on the rest of the car.

[davey g-force]

Re: MT300 and paint correction on Mercedes GL450

No need to strip the Black Wax off.

[Meticulous-Detail]

Re: MT300 and paint correction on Mercedes GL450

Post some pics of your work and problem areas, it will help us see what your dealing with an how much you have accomplished.

[AlexSD]

Re: MT300 and paint correction on Mercedes GL450

Guys,

Thank you for all of your advise and insight. I spent about 4 hours today working on the car's roof. It was in really bad shape with tons of swirl marks and etching from bird drop. I took my time, taped the rails and all rubber parts with blue tape before starting out. Used red foam pad with UC working VERY slowly at 5800 OPM. Cleaned the pad with the brush after each section to minimize dusting. Applied UP during the second step and finished it off with Ultimate Liquid Wax.

Quick question about applying wax with black polishing pad. I ran DA at 3800 OPM while applying wax and the pad barely rotated if I put any pressure on the handle. I ended up using VERY light pressure to let DA rotate and spread the wax around the roof. Is this normal? I guess I am not really polishing the paint and merely spreading the wax as the final step. But I just wanted to confirm with professionals on this forum.

I plan to do 3-4 panels tomorrow if I have enough time and will take pictures before and after. Overall I am very happy with the results -- it's not 100% perfect but the car is a daily driver and I can live with some minor imperfections.

Now, here is a picture of the problem area on top of the car that I don't know how to address (yet). This is a moon roof that was probably spayed at the factory with clear coat. Now, the clear coat is peeling off. I welcome any suggestions on how to make it prettier.

[IM]

[davey g-force]

Re: MT300 and paint correction on Mercedes GL450

I take it that third pic is the completed section? Nice work

So is the moonroof glass with a clear coat? Or plastic? How does it look in the areas where the clear coat has gone?

[The Guz]

Re: MT300 and paint correction on Mercedes GL450

Looks pretty good but it looks like some clear coat is coming off. If it is I would not polish that area.

As far as your question of the pad not spinning, that is ok. You only need the weight of the machine to spread wax.