Outbreak of spots

[Deleted]

Last sunny week I proudly polished the rover, the next day I noticed spots the size of 10p's all over the car. Tried to polish them out but they are still there, even after T-cut. Any suggestions? Colour is bordeaux red i think.

[johnwp5bcoupe]

A light T cut may do it try on a small area that is not too much in view like the middle of your bonnet

[theroveringmember]

Bordeaux is notorious for this when it's a few years old along with all other shades of Maroon & some blues I think. I polished our 110 a couple of weeks back & I have them on the boot & the tops of the wings now (which are Stone Grey) where the water sat after some rain. You only get them on the horizontal surfaces where the water sits. They normally polish out o.k. You don't mention rain & say they're all over the car. Does that include the sides? I've only ever got them after rain or washing the car in the sun (bad practice) & they take the shape of the water droplet.

[Deleted]

Spot on. They are on just the horizontal surfaces where the water sits. Looks like another session of polishing.

[dorsetflyer]

This has been covered several times before and it's the strong sunlight through the water droplets.
The droplets act as a magnifying glass, and with the UV of the suns output, actually burns the surface of the paint. That's why you end up having to 'T' cut it before polishing.
Although reds and maroon are the worst affected it does apply to most of all available colours to some extent.
Older paints, like cellulose and acrylics are more affected than the modern finishes.
Yes, don't wash your car in bright sunlight, and if you are out at a show and get caught out by a shower, if you've got a 'chammy' then it doesn't take long to get the water off, especially on horizontal surfaces.
I nearly always have one in the boot, and I do admit I get a lot of stick from my friends about leathering off after a shower but then I don't have any problems with water marks as a result.
Unfortunately there is nothing you can do about it unless you have an expensive re-spray.

[Deleted]

I dont remember this problem in the late 60s when I started driving. Some say it is due to the UV content of the light that is causing the problems, not just to paint.

[stantondavies]

It has always been a problem Humphrey. Often affects the wax polish, but normally not a problem to clean off with T cut.
Red paint seems the most susceptible to sun damage, though bizarrely it seems to affect panels more than the body - faded bonnets and bootlids but roof OK. I can't think of an explanation for this dichotomy.

[dorsetflyer]

Peter I can assure you it does affect the roof panel as well as the others. I can remember having three cars in the sixties/sevenites which all had the same problem on any horizontal surface.
I still have slight problems on my Zircon Blue saloon, except where it was resprayed in two pack after my brush with the 4 x 4.
Also the Juniper Green 3 litre coupe has the same problem but not to a great extent.
It is quite rightly the UV light that comes from the sun that causes the damage not only to paint but plastics of all kind, leather, carpets, and probably worst of all any rubber based products.

[Warwick (Ozcoupe)]

There is another possibility too, but I can't verify it.

A new automatic carwash was installed beside my office building a few years ago and it's one of the brushless type - just water sprays. The blurb on the sign says that the final rinse is done with demineralized water to stop the spotting of the paintwork that occurs when tap water droplets are allowed to dry.

[dorsetflyer]

Most of our water over here will have either chalk or limestone in it. This results in a slight whiteish spot on the paintwork if it's allowed to dry naturally. There are very few areas where the water is soft enough for this not to happen.
De-mineralised water is the same as distilled water and to rinse a car would be hellishly expensive. Not quite so bad if you could re-cycle it though.
The moral of this is don't wash the car in direct sunlight.

[Warwick (Ozcoupe)]

dorsetflyer said:

De-mineralised water is the same as distilled water and to rinse a car would be hellishly expensive. Not quite so bad if you could re-cycle it though.

You're right of course, John.
Wasn't suggesting a rinse down with special water at home. The carwash uses rainwater from the nearby building's roof and recycles it all. It has a separate set-up to produce enough de-min water for the rinsing.
I just mentioned it to give another reason why a chamois is used.

[Deleted]

Thanks all. As soon as it stops raining I will give it a go and let you know the outcome.

[stantondavies]

It was always said that the best time to wash a car was when it was raining. The rain softens the dirt and aids rinsing the car.

[jimjam]

Once you've got rid of the spots with T-cut, 'splash-out' on some expensive polish with UV protection - there are plenty around. This should help reduce the problem and if done regularly will form a film of protection over the paint. Can't remember which one I use now but it is hellishly expensive. Beautiful shine though!

[Deleted]

For those with de-humidifiers in their garage,a rinsewith distilled water might be a possibility

[Deleted]

If the wife hasn't used it for the iron!!