Second attempt at DA polishing - technique and hard to reach places

[Bill1975]

This past week I have the chance to polish out my carbon steel gray VW GTI. (Pictures we`re taking two days after the detail and has been parked outside. ) I had even better success than last time in removing swirls and holograms, but I still have a few questions.

First, my process was:

Wash with ONR, following with a claybar and drying immediately

Compound roof with a yellow LC pad, Optimum Compound, polisher on a speed of 5

Polish with a PC 7424xp, Optimum Polish II and flat LC orange pads. Speed of 4. 3-4 section passes per area.

Apply Optimum Poliseal with a black pad at a speed of 2. Remove with a MF bonnet.

Use of a DIY LED work light was very effective in exposing hologram and residue from polish and wax.

Questions:


1) The first time, I used a high speed (5-6) and more pressure, this time used a slower speed (4) and less pressure. I got good results, but I`m increasingly aware of how much the pad slows down even with a small amount of pressure. It felt like I was barely touching the surface with the pad, especially on vertical panels where it was difficult to get the pad exactly parallel with the surface. Is it generally better to use less pressure in a slower speed? Or are there times where more pressure would be better?

2) The whole process took about 8 hours, which includes analyzing a couple of test spots. How can I be more efficient and take less time? Wash and Clay took an hour. When polishing, I`m taking about 10 seconds to make a single pass of 18"-24". Trying to brush pads periodically and changing them out frequently. Using a work light to go back and check my work.

3) There is a small area along the roof , where there is a small depression in the panel (see picture of roof, area is circled in red). As a result the pad doesn`t make full contact and I can`t get any effective correction in that area . How do you attack spots like this?

4) There are still some deep scratches on the roof. Even after compound and polish. Is there a more aggressive combo that I can use without having to call in a pro with a rotary?

https://uploads.tapatalk-cdn.com/20170728/597915569f6e55d35e6e8458986c9781.jpghttps://uploads.tapatalk-cdn.com/20170728/bbd55ff477cc8e2833cfbcbb9d0a6b55.jpghttps://uploads.tapatalk-cdn.com/20170728/110eed2f15b67f4697c6dbde8b4caaf9.jpg

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[EdLancer]

Some scratches are just too deep to be corrected, but rounding the edge of the scratch will deflect light making it less visible. If you can get a 90% improvement that is 90% visually better than before. Do all the area where the pad can`t reach first by using a little polish on a MF and use you finger in circular motion like a spit shine.
Do this for the areas under the door handles and the dent on your roof. The pressure from your finger is more than the pad will ever provide.
Before the DA in the 80`s car enthusiasts polished their cars all by hand one panel a day !

[BudgetPlan1]

Megs D300 w microfiber cutting discs can do some heavy lifting.

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[LawrenceSA]

1) Or are there times where more pressure would be better?

I have always found that increased pressure seems to add more heat into the equation and leads to more pad stall on a free floating DA. For me, pad rotation is more important

2) The whole process took about 8 hours, which includes analyzing a couple of test spots. How can I be more efficient and take less time?
8 hours to compound and polish doesn`t seem all that long - it will usually take me longer, especially on harder VW paint. In fact, usually compounding alone can take me that long

3) There is a small area along the roof , where there is a small depression in the panel (see picture of roof, area is circled in red). As a result the pad doesn`t make full contact and I can`t get any effective correction in that area . How do you attack spots like this?
I work on a lot of VW`s and a small trick is to run a piece of tape along the ridge that sticks up above the roof, allowing to you tilt your pad into that channel without having the pad constantly be rubbing up against the bit that sticks up higher than the roof.

4) There are still some deep scratches on the roof. Even after compound and polish. Is there a more aggressive combo that I can use without having to call in a pro with a rotary?

If it is a daily driver, perhaps you need to learn to live with some of the deeper scratches as removing too much clear coat could accelarate the onset of clear coat failure. Given that it is on the roof where (a) they are probably harder to spot and b) the sun and other negative elements are going to hammer that panel and c) in the absence of a PTG, I`d seriously consider living with them

[Accumulator]

My views on the Qs:

1) I generally agree that more rotation is good, but I do often find that applied pressure is simply required to get the job done with that kind of machine. It can be a fine line between "enough pressure to be more effective" and "too much pressure, makes it bog down".

I`d ditch the LC Yellow (which I utterly despise for anything other than backing up a MF bonnet) and try using a MF Cutting Disk instead.

And while everybody has their faves and their also-rans, I`d replace that Optimum Compound with M101. The Optimum is one of the rare products that I simply threw in the trash while M101 is so effective you have to be just a little careful that you don`t get carried away by getting too Autopian about things (see #4 below ;) ).

2) IMO you`re working pretty fast already. I can spend hours on a single panel and you probably wouldn`t believe how long it takes me to do a "quick maintenance wash" even if I skip the undercarriage/engine compartment.

Switching to the MF disks should save time- cut faster and clean up much faster/easier (especially if you blow `em out with an air compressor). I won`t waste time trying to clean out foam pads! If wiping with a cotton towel doesn`t do it, I get out a new pad, period.

A lot of it is just familiarity and getting your routine down...IME efficiency comes naturally with experience, so I`d focus on efficacy instead; do the job right and just let it take as long as it takes.

Oh, and just FWIW, I don`t work areas that large. Guess it`s just a personal preference, but I like to work smallish areas, even when using a polisher that`s well-suited to the "usual" 24" x 24". Haven`t done that big an area since I was using a rotary, at least not for significant correction (Finish Polishing can be different).

3) Do odd/tricky spots by hand. Easy with something like M101.

4) LEAVE THEM BE! Anything that can be fixed via rotary can be fixed (albeit slower) via more gentle means (they didn`t need rotaries/etc. to carve marble blocks into smooth-as-glass classical statuary ;) )...and/but that doesn`t mean you oughta do it, especially not on the topmost horizontal panel. You need THICK clear up there to stand up to UV rays. These days it`s easy to take off a LOT of clear, and it`s gonna bite a whole lotta folks a few years down the road. The amount of clear that can be *safely* removed is incredibly minimal.


Before the DA in the 80`s car enthusiasts polished their cars all by hand one panel a day !

Ain`t THAT the truth?!? Heh heh, working by hand 40 years ago, I`d spend a lot more than a day per panel on single stage white :D But then, gee...I can still spend a day on one panel, even with the most potent combos...slowly can = safely for me. The speed with which some people do this stuff simply amazes me, I`m just not that guy.

[Bill1975]

Some scratches are just too deep to be corrected, but rounding the edge of the scratch will deflect light making it less visible. If you can get a 90% improvement that is 90% visually better than before. Do all the area where the pad can`t reach first by using a little polish on a MF and use you finger in circular motion like a spit shine.


Thanks, I will try this. Even if it can reduce the appearance I will be happy.



Megs D300 w microfiber cutting discs can do some heavy lifting.

Sent from my SM-G930T using Tapatalk

I might give these a shot, as I`ve seen them discussed before!

[Bill1975]

1) Or are there times where more pressure would be better?

I have always found that increased pressure seems to add more heat into the equation and leads to more pad stall on a free floating DA. For me, pad rotation is more important

I noticed that its much easier to stall the pad at lower speeds. I think feeling the vibration of the machine it makes one think the pad is working, but after marking the backing plate I realized I was overdoing it. My approach this time was to put just enough pressure to slow the pad a small amount, which was very little. I suppose I was laboring under the impression that one really needs to "dig in" when doing this sort of work.


2) The whole process took about 8 hours, which includes analyzing a couple of test spots. How can I be more efficient and take less time?
8 hours to compound and polish doesn`t seem all that long - it will usually take me longer, especially on harder VW paint. In fact, usually compounding alone can take me that long

My only comparison is when I had a pro work on my last VW requiring a similar amount of work. When worked by himself it was 3 (maybe 4 at the most) hours, and with a helper it was down to two. Usually he would wash, do a test spot, and polish, and would hit a couple spots with a more aggressive method, and then finish with wax/sealant, wipe down the dash and vacuum the interior. Not that I can get as fast a professional, but as it is now it is very tiring, not to mention the strain on my back.


3) There is a small area along the roof , where there is a small depression in the panel (see picture of roof, area is circled in red). As a result the pad doesn`t make full contact and I can`t get any effective correction in that area . How do you attack spots like this?
I work on a lot of VW`s and a small trick is to run a piece of tape along the ridge that sticks up above the roof, allowing to you tilt your pad into that channel without having the pad constantly be rubbing up against the bit that sticks up higher than the roof.

Thanks, good idea. I`ve also wondered if a 3" backing plate/pad combo would work?


4) There are still some deep scratches on the roof. Even after compound and polish. Is there a more aggressive combo that I can use without having to call in a pro with a rotary?

If it is a daily driver, perhaps you need to learn to live with some of the deeper scratches as removing too much clear coat could accelarate the onset of clear coat failure. Given that it is on the roof where (a) they are probably harder to spot and b) the sun and other negative elements are going to hammer that panel and c) in the absence of a PTG, I`d seriously consider living with them

Yes, it`s a DD. I realize it won`t be perfect and the remaining defects I can live with. 99% of people would probably not even notice. But, for the sake of learning and improving I wanted to see if there was anything else I can do. Given that I drive 20k miles a year and live in Texas, I`m sure that part of the car takes a beating as it is.

[Bill1975]

My views on the Qs:

1) I generally agree that more rotation is good, but I do often find that applied pressure is simply required to get the job done with that kind of machine. It can be a fine line between "enough pressure to be more effective" and "too much pressure, makes it bog down".

Based on the advice I`ve received to use the least abrasive first, I think lower pressure and speed is probably a good default approach from now on. Like I said earlier it was surprising how little pressure is needed. It was much more difficult on the curved door panels not to stall it.




Switching to the MF disks should save time- cut faster and clean up much faster/easier (especially if you blow `em out with an air compressor). I won`t waste time trying to clean out foam pads! If wiping with a cotton towel doesn`t do it, I get out a new pad, period.

A lot of it is just familiarity and getting your routine down...IME efficiency comes naturally with experience, so I`d focus on efficacy instead; do the job right and just let it take as long as it takes.

I think two of the things that helped vs my first detail was 1) I had some BRIGHT daylight color LED lights. They were most effective when I closed and darkened the garage. And 2) The first time I used 3 pads of each type for the whole car. This time I used 6. I think this is how I was able to avoid some of the residual holograms from last time.

[EdLancer]

Based on the advice I`ve received to use the least abrasive first, I think lower pressure and speed is probably a good default approach from now on. Like I said earlier it was surprising how little pressure is needed. It was much more difficult on the curved door panels not to stall it.



I think two of the things that helped vs my first detail was 1) I had some BRIGHT daylight color LED lights. They were most effective when I closed and darkened the garage. And 2) The first time I used 3 pads of each type for the whole car. This time I used 6. I think this is how I was able to avoid some of the residual holograms from last time.

That is whole lot of pads. With experience you will find that 1-2 white polishing pad is all that you need. Once you done a proper polish the paint will just get better each year you do it and it becomes much more easier and faster. I get a chuckle every time I am out detailing and people who walk by and say my car is shiny, little do they know I haven`t even started polishing it yet it was just a quick wash and the shine was from last years detail ...LoL

[Accumulator]

EdLancer- Heh heh, another fence you and I are on different sides of! Per usual it`s nothing right/wrong...just that I use a LOT of pads, even for the polishing step (not too many if/when burnishing/etc.). Maybe it`s because I don`t want to stop and do a lot of pad-cleaning, or maybe I`m just erring WAY on the side of caution about dead product/cut-off clear..(emphasis on the "erring" ;) ).

And yeah, it *is* sorta funny when people think we just did a major detail or something and it`s simply an OLD detail that hasn`t gotten messed up :D

Bill1975- This might be YET ANOTHER thing where I`m, uhm...outside the box, but I basically do all my PC-type correction work at 5 or 6.

And that`s good thinking on your part regarding the roof taking a beating from the sun.

Also, your absolutely right about how the right lighting, especially in an otherwise dark environment, can make all the difference!

Sounds to me like you`re getting dialed-in pretty quickly, even if it doesn`t always seem that way.

[Bill1975]

Thanks, I am getting there. And yes, when I posted back in December or January I mentioned only using three pads for the whole car and I received several comments that I would need more or have to do a lot of cleaning of each pad. I also noticed that after that first detail there was a lot of product gunk in the pads that made it hard to clean. It just seems easier to change pads and have to clean after every panel. I probably could have kick the speed up a bit more, but it`s getting there.

My first impression was that the metallic flakes did not pop as much as they did the first time. Maybe it`s my imagination or maybe the slightly more aggressive polishing helped.

Either way it came out pretty well I think. Considering the botched wash job I got from an otherwise great body shop I had a lot of work to do. The picture below shows what I was starting with
https://uploads.tapatalk-cdn.com/20170729/e39ece3dc7b21cb1d188224c6973e616.jpg

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[Accumulator]

Bill1975- Yikes, you did have your work cut out for you!

And yeah, I`d rather change pads and keep working too. I just clean `em all out when I`m finished for the day..might oughta refine that so the product doesn`t dry in them first, but eh...I`ll get around to that. Maybe ;)

HJey, that`s interesting that you don`t notice the same metallic pop this time! Wonder what`s up with that....

[Bill1975]

Well, it could be my imagination. They do have "pop" but the first time I did my work in strong sunlight, this time it was in the garage and afterwards it was a bit cloudy. Who knows...

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