A polishing test spot is the starting point and foundation for any paint correction detail. It is the point where we can conduct a TEST to see which combination of products and techniques give us the best results. At this point, we can gauge the effectiveness of our polishing process and change certain variables based on what we are trying to achieve. The test spot allows us to dial in a process that can be replicated across all painted panels. Keep testing, and the perfect combination will present itself. I hope you enjoy the video!

Polishing Variables

1. Machine
2. Backing Plate
3. Pad
4. Liquid (Polish or Compound)
5. Pressure
6. Machine Speed
7. Arm Speed

Common Paint Defect Types

1. Swirl Marks
2. Deep Scratches
3. Hazing
4. Sanding Marks
5. Oxidation
6. Etchings

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Video Transcription

Hey guys, James here at the Auto Nuvo shop and today I want to talk about the test spot, the variables that go into it and we’re working on a 2002 BMW m5. Massive project and I thought we you know with this project we’re gonna have the opportunity to kind of take you on different intervals as we kind of go through this project and I thought that would be kind of cool. So we’re at the test spot interval we just got the front end the hood and fenders back from the body shop so those have been repainted. We’re gonna be sending the wheels out, coatings, multistage correction, all that kind of stuff. So excited about this but we’re at the test spot phase and we just washed and decontaminated it. It’s clean and now we’re kind of assessing the paintwork and figuring out okay, what is it gonna with our approach what machine could pad polish combination are we gonna use to get the result that we’re looking for. In my opinion that analysis starts back to the client consultation when you’re when you’re first going over the car with the client figuring out the history. That’s where you’re asking the client okay is our any panel’s repainted you know who was the previous owner, are you the owner, all that kind of stuff comes into play when you’re trying to figure it out. In our case we repainted the hood and fenders so we now know okay we have to approach those panels a little bit differently than say this original panel. Same thing goes for plastic vs steel or aluminum or composite or carbon fiber. All those different materials are gonna react differently to polishing and knowing that ahead of time is gonna help you plan better. So then, kind of my first step in approaching a test spot is to kind of go through our safety checks and the first one is kind of a visual inspection after an isopropyl alcohol in this case 50-50 mixture. I’m going to just basically give the paint a wipe down just to remove any residues that might be on the surface so I can see the true condition of the paint. That’s where we have our Scangrip lights we’re inspecting the paint and we’re seeing what type of defect we’re trying to chase after because that will also help determine the pad polish machine combination. Is it swirl marks, is it light scratches, is it hazing is it oxidation, is it sanding marks. All those different things you might have to adjust your approach based on what you’re trying to remove. After that point we go into our paint measurement in this case using an ultrasonic tape depth gauge we’re just seeing kind of what’s going on I give this a little bit earlier and we’re averaging out about a hundred eighty microns. So very very safe but the reason we’re doing this is because through a compounding or even a polishing process we’re removing microscopic levels of material or clear cote. When we’re in the process of removing these defects were basically shaving away a microscopic layer of clear coat which is a top layer that’s the only layer that we’re polishing on and in this project, we’re trying to maximize the look. We’re trying to get it that 10% further to make the vehicle look fantastic. But at the same time, we want to think about it from a preservation standpoint we don’t want to risk it and end up having to repaint the whole car, we don’t want to do that. So we want to safely fix, you know fix the paint, polish the paint, but make sure that we’re doing it in the safest way possible in the least aggressive method possible. During what we also did our visual inspection, we’re also kind of in our heads, you know the more you polish paint in messing around with different cars the more preconceived notions you’re gonna have about, okay, German BMW metallic clear coat paint. It’s gonna be on the harder side right so you might have some pre-loaded combinations ready to go which is gonna help you how to speed up the test spot process right, if we started with just a polishing foam pad and like just a you know a relatively light polish, we’re probably not gonna get the result we want right. But it might be worth to try if it has potential. Right in this case I know you know I’m just working on these particular paints before, that most likely we’re gonna have to use a heavy cut compound and cutting pad in order to remove the heavy swirls and scratches that are in the paint. Because this paint, I mean, you know, it’s a 2002 car. It’s been washed a lot, it’s it’s in fantastic shape, it’s just we have to kind of remove the wash marks and the wipe down marks. Which inevitably have been, you know, have happened probably a thousand times over its life so far. So, then you know once we kind of figure out, okay let’s go heavy cup compound, let’s go microfiber cutting pad, and let’s see her a result. Let’s kind of talk about the variables that go into that. The actual putting the machine onto the paint. So the first thing I do since since we’ve selected a cutting disk we’ve selected Meguiar’s m101 the first thing I’m gonna do is I’m gonna prime the pad. So I’m gonna put a pretty serious amount of compound on there right now an basically what I’m doing, as I rub this into the pad, is I want to coat each one of these fibers with, with abrasives. To kind of unleash the cutting potential of this pad and so typically you have to add a little bit more here and there to kind of get it fully coated. But that’s really gonna maximize the potential of what this pad is designed to do which is cut the paint. So after we do that I’m typically and this the amount of polish compound in this case that you decide to use is also gonna be kind of you’re gonna mess around with your choice of how much liquid is gonna be on the pad. That’s gonna be based on the what type of paint you’re working on, so you might have to use a little bit more, a little bit less, that’s what the test spot is all about, is to figure out you know how much and all that kind of stuff. So let’s go right into it. In this case right so we have M101, we have a microfiber cutting disc, we have the Rupes 21. That’s kind of our three at least initial variables that were selecting based on, okay, we’ve worked on a similar car before, this should work out. Now also say that in a lot of cases just because it’s the same car, same year, same paint there could be, you know we could have the one that’s completely different, painted somewhere else and we’re gonna get a totally new set of variables thrown at us. So just something to think about don’t get discouraged if the result doesn’t go your way that’s what this test spot is all about. When I typically do a test spot I typically work in a smaller, you know two by two section in a smaller section to kind of test it out. But make sure that as you’re doing this you know sometimes, I’ve seen guys will do a small test spot but then as they kind of are going through the project will open it up to a bigger section. Well then if you do that, the result might not be the same. So something to think about, same thing with residue management at if you want this result your test spot results to be exactly the same as everywhere else on the car you have to make sure that the variables are always the same. Which means we’re starting out with a fresh clean pad, it has no residue, no paint residue, no spent abrasives. As you move this pad will get dirty, clear coat is gonna be on here now, spent abrasives that are toast, are gonna be on here now, you want to be cleaning that constantly or switching to a new pad as you move along so that you can mimic this result everywhere else. I think that’s one of the most important, important things to to realize when you’re doing a test spot. If you want this result you have to make sure that all the variables that you selected for this result are then mimicked everywhere else on the car. Big big big one for me, but let’s go right into it, let’s do our test spot and let’s talk a little bit about the variables. Okay so now we got inspection time, let’s see what’s going on. So … and obviously always adjust your light height, in some cases too, sometimes if you’re super close with a light light like this, on a lightly colored paint it it kind of almost floods it out and you’re not really seeing what’s going on. As you raise it up all of a sudden it’s like a little micro marring, oh I got a rid of here, so that’s another thing to think about. In this case what m101 is doing is leveling the swirls and scratches. A couple rids that might be unsafe to chase, they might be, as well we’re gonna have to test that out a little bit. But it’s leaving a really nice finish, which means this is a super super hard paint. If we were doing BMW jet-black, M101 would be way too aggressive, but in this case it’s perfect. We’re good then we can go right into our polishing process and that polishing process is gonna be relatively quick because we’re removing all the defects here and we’re just coming in with a polishing pad and something like maybe Meguiar’s M210 just to refine the finish, extract as much gloss as possible, and then you’re good to go. The variables that I want, that I think are also important to mention, when I’m approaching this process here is machine speed, arm speed, pressure, tilt, you know backing plate tilt, well that kind of stuff comes into play. In this case I was running at about speed 4, I would call it medium to firm pressure, decent amount of pressure, slow arm movements to allow the abrasives and the pad to work. I had not a ton of pad tilt in this case, I think pad tilts gonna come more into play as I approach a lot of these edges and I’m wanting to get the same level of contact on an edge in the same level as those result as I got in this flatter section. But all those variables, those polishing variables, is just something you want to be thinking about and as you approach your test spot test them out this is the time to spend, this is the time to spend more time to figure it out now so then you can dial in a process and then crush it on the rest of the car and maximize your time and efficiency. You know I really hope this helped, this is a video I’ve been wanting to make for a while. Comment below with any questions at, all if you guys have any anything to add to the equation and test spot you know craziness would love to hear from you guys. See you guys next time!