Do circular motions actually cause swirls and scratches or is there something more to them than meets the naked eye?
I think People tend to jump to the conclusion that circular motions cause swirl marks and scratches because they appear circular and while on the surface (no pun intended) that seems plausible enough it’s actually not the case and is where the core of the misconception lies.
The truth is that swirl marks aren’t actually circular but are in fact a collection of close-knit, interlocking straight scratches that just appear circular to the naked eye under a direct light source but once you examine them up close you can soon see how these supposedly circular scratches are for the most part anything but.
It’s kind of an optical illusion that causes your eyes to trick your brain into thinking the abrasions are circular, yet coordinating your entire car cleaning routine around something illusory probably isn’t the best idea.
Granted, a certain proportion of these marks will be somewhat circular but in most cases of ‘swirlitis’ the vast majority will be made up of smaller, overlapping linear scratches that just give the impression they’re circular when viewed from a distance. Now, this was the closest I could get to the surface here without losing focus but I’m sure with the right lens and light you could magnify things even more to show the so called swirls in all their true undeviating glory.
And it’s worth mentioning that name used to describe these scratches because surely if the vast majority of them aren’t even circular then referring to them as “swirl marks” only contributes to the confusion. Indiscriminate scratches or trick-of-the-light-marks would be more appropriate but then I guess neither of those has the same ring to it, either way my point is that the standard terminology is a bit misleading.
Once you grasp all this you should quickly realise that in terms of potentially inflicting scratches the motion you choose really isn’t all that important as it’s not the type of movement that inflicts the scratch but the dirt particle trapped between the surface and whatever’s being drawn across it.
And while I feel I could technically just leave it there as that’s really all it boils down to, I’ll do my best to expand on the subject some more and explain why despite everything I’ve just said, using straight lines is still sometimes preferable.
Aside from a few rare instances washing in circular motions generally just isn’t good practice, not necessarily because it inflict’s more swirls but because it’s kind of inefficient and disorderly. Working in a linear fashion on the other hand is definitely the more mindful approach to cleaning a car and in that sense is superior as the methodology behind it means that you’re far less likely to miss any spots.
That being said there’s naturally going to be certain parts of car that’d be more suited to being cleaned in circular motions, for example it makes perfect sense to want to wash and perhaps dry the headlights of this 911 in circles, whereas attending to its sleek rear lamps and slatted boot lid would call for the more methodical back and forth approach.
Providing the surface is as contaminant free as possible prior to contact washing then using circular or straight motions on panels like the bonnet of this GTS really isn’t going to make a blind bit of difference in terms of inflicting scratches and swirls. The way I see it is that you want be able to comfortably get to grips with the surface and give it a decent clean without having to worry about damage you may or may not be inflicting which just spoils the fun in my opinion.
Despite technically being able to safely wash the roof or bonnet of a car like this using circular motions though, you really don’t want to wash the sides of a mucky motor in this manner as you’re far more likely to pick up contaminants from the generally dirtier lower parts which could lead to scratches and swirls being inflicted as the mitt circulates. A more controlled top-down linear approach on the other hand will ensure these dirtier areas are hit last.
On the whole, wether washing or drying I myself prefer to use a more free-flowing or sweeping motion that generally follows the contours of the car which I guess you could say is kind of a combination of the two techniques. It’s efficient enough, provides a quality clean, in my experience is perfectly safe and it just feels far more organic than rigidly sticking to one strict movement so, go with the flow, I say!
Certain aspects of the detailing process like claying for example should be undertaken in a linear fashion, not because doing it this way is less likely to inflict damage but simply because it picks up more contamination this way. As with washing, working in a more linear flowing manner ensures all areas are throughly covered, whereas if you clayed a car in circles small unseen areas of bonded surface contaminants would likely be left behind.
The linear-only approach that should be applied to claying a car needn’t be undertaken when polishing one however as the specific motion really doesn’t matter, what does is that the applicator you have is contaminant free and that the product (assuming it’s fit for the job) is thoroughly worked in and broken down. I personally like to combine the two, first spreading the product in a circular motion before working it in back and forth.
And because polish products need to have their ingredients properly broken down, working them in with just one movement isn’t adequate enough to achieve a decent finish in my opinion. If you picture the tiny abrasives just being rolled over the surface in one direction they aren’t going to be able to attack all the scratches properly nor finish down fully which is why I like to try and work every which way to ensure the imperfections and abrasives are hit from all angles.
If, say an overly abrasive product is worked in by hand using only circular motions then yes you’ll likely be left with circular scratching but similarly if you only use back and forth motions to work it over the surface then you’ll be left with a load of linear scratches, neither of which are particularly desirable.
Now unfortunately I didn’t have a machine on me for this job but the the point I would have attempted to make if I did would be that surely if circular motions caused swirls then machine polishing which works primarily in circles would inflict them which would be pretty counterproductive considering generally that’s what we’re attempting to remove by using them.
Sure, in the wrong hands they’ll inflict buffer trails and holograms but they’re both very different things than circular scratches or swirl marks, so machine polishers therefore kind of prove than in certain respects circular motions are actually great at removing swirl marks, not inflicting them.
When finishing a freshly polished car with a wax or sealant people think this is where you need to be the most careful if you’re not to undo all your hard work and so avoid circular motions like the plague. This isn’t entirely necessary though as protective products like these don’t contain any abrasives, so assuming the pad and towel you use are clean the motion in which you choose to lay them onto and buff them off the surface really isn’t important, what is, is ensuring even and complete coverage. I suggest naturally following the contours of the car but others may be better at achieving this with circular motions which is absolutely fine.
So to wrap things up then, instead of stressing about scratches being inflicted think about the products you’re using and what stage of the process you’re at and ask yourself whether the motion actually matters. Next, devise a plan of action that’ll allow you to tend to your car in the safest and most efficient manner possible and if that happens to include some circular motions here and there then that’s not necessarily a bad thing.
If you personally feel more comfortable detailing strictly in straight lines then go for it and be confident in your technique but understand that circular motions don’t inherently cause scratches and that aside from around the dirtier lower areas of a car, you’re not actually safeguarding against damage by actively avoiding them.