Swirl Marks

[WhipLash]

Is there any quick 'N easy solution to swill marks in the paint? By swirl marks I mean the tiny marks in the paint that are usually only visible when the sun shines on the paintwork. I wouldn't classify them as scratches, although they may be microscopic ones.

I don't know what causes them, maybe they are a feature of metallic paint? Or perhaps the manufacturers paint application process was flawed? The reason I say this is that I've seen a few new cars in showrooms that have them already. They are mostly noticeable in dark metallic colours like blue or black.

Any ideas anyone?

[BeCos]

Yeah .........you cant !

You cant get rid of them because they aren't there !!

What I mean is if you are in a showroom with the spotlights shining onto the bonnet of a car and you see all the scratches then the chances are if you try to focus on them and then move your head the scratches will move too !

It's an optical illusion and I used to get asked that every week in the garage!

Of course you could also be talking about scratches that are there, and you can sometimes polish them out.........blah blah blah.......the rest is history!

[Phil]

Was this before or after a couple of pints??:D

[WhipLash]

These illusional swirls marks you refer to Ben, what causes it? Is it only so as the car is under spot lights? I've seen such swirl marks too in garage forecourts on new cars also, and on newish used cars too.

I'd say they aren't scratches, as they aren’t localised to one particular area, but the whole car, depending on the angle you are looking of course.


Strange, but annoying all the same!

[BeCos]

Sorry I can explain it any better, scientifically, but it is an illusion !!

Very annoying !

[BrianS]

Nah, its not an illusion - there are scratches there, though very fine. The manufacturers do some wet-sanding of the paint, I think its before they put the clearcoat over it but I'm not 100% sure. There's a girl here with a new black Hyundai Coupe and it looks moxy when you are close-up on a Sunny day. That's the problem with dark cars. The imperfections show up a lot more than on a light car.


There's very little you can do about the swirls at this level because they are beneath the surface. Give the car a coat of good wax - if you get a nice deep shine, people will be too busy admiring their reflection to notice the microscratches!

Later,

Brian.

[BeCos]

The manufacturers do some wet-sanding of the paint

Since when ?

[BrianS]

Good point, Ben. Everything is sprayed on at the manufacturing plant and wet-sanding would slow the production line down, wouldn't it. Somebody mentioned the wet-sanding to me before and I never thought about it until now. It just seemed to make sense as we were having a look at the swirls on his car one day, but now that I think about it, that process has long gone (esp.with the introduction of automation). Nowadays, paint is just sprayed on - a bit like the Picasso ad but a lot messier than they would have you believe(!). They use rotary bells with air-atomising spray guns to spray the liquid coats on. (There’s only one plant in the world, BMW in Dinglefing, Germany, that uses a powder coating process. The powder melts and forms the coating.).

So what causes swirls at this level? I'll check further but this is what I “think” the cause is: the material being applied to the car is negatively charged and the car is positively charged. This “draws” the material onto the surface and so everything is applied evenly. However, it is applied with an “atomising bell” – basically a bell shaped spray nozzle that spins at high speed, spreading the material over the surface. I think it must be the high speed spinning that forms the patterns on the surface, thus giving the impression of swirls when a bright light reflects off it. This is just my theory, but I’ll see if I can find out how wrong I am! Who knows, maybe they actually do a bit of wet sanding – the guy I heard it from usually knows his stuff. We’re only human, as they say or maybe just thick sometimes!!

Have a look at the picture below. Everything up to and including the base coat uses the atomizing bell in its application. The clearcoat is applied through a couple of separate coatings before going off to the baking process. Its a lot thicker than the basecoat for the extra protection.

Take Care Out There,

Brian

[WhipLash]

That’s both very interesting and informative Brian!

I wonder do these swirl marks only occur on particular cars, batches of cars, or for all particular models/makes depending on the process used or the plant they were manufactured?

If it just affects batches of cars, what are the chances that one could turn down the collection of a new car based on the paint not being of an acceptable standard?

[BrianS]

On a more expensive luxury or "fancy" car, the polyurethane paint is of a very high quality so the occurrence of stuff like this is minimized. I suppose if you're not happy with the appearance of the car, you shouldn't be forced into accepting it - statutory rights, consumer rights, etc.

What type of cars were you looking at, Whiplash. I don't think its down to faulty batches out of the car plants. Next time you're in a showroom, have a look at more of the cars. See if its more visible on the cheaper ranges than the ones you would be looking at (lol). With closer examination, you'll probably see it on all the cars, but some will be a bit worse than others. You may not have to worry though - I hear pink cars don't show it so much.....:p

[BeCos]

I really dont think there is a cure for this.

As I said before if you see these mark, at least the ones I'm talking about they will move if you move your gaze, hence they aren't there. They are just some curious reflection thingy and are worse on darker colours due to the way they reflect the light.

It's down to colours and the actual lighting involved !