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The amount of dust is a fairly significant layer..

So you suggest to use a bucket with lquid soap?
What is the purposel of the soap ??
polishing effect??? or does it wipe the dust off?

And if I use a 2500 grid wetsanding paper,
does this remove the gloss of the paint??
or does this only remove the dust and not the gloss?



Ok... soap basics 101... the way in which all soaps work is this... the soap molecules encapsulate ( surround ) the dirt, dust, grease particles. Once those elements are encapsulated by the soap molecules, it allows you to rinse them off and they can no longer cling to each other. Since the soap encapsulation forms a strong bond around the dirt particles, it helps to break the bond of the dirt particles that hold it to the surface of the car, or your hair, or your skin etc. That is why the crap on the surface of those various surfaces are referred to as 'surfactants' - in that they are crap on the surface... ( bird poo for this purpose could be politely called a surfactant - even though 'bird poo' is a more descriptive term.

The one thing you have to look out for.. is that I was recommending liquid dish detergent. You have to make sure that it is not one of those 'liquid dish detergents' that has chemicals in it that are designed to stay on the surface that is being cleaned. For example, some dish detergents have vitamin E in them, aloe vera and other things designed to 'make your hands lovlier and softer after washing by hand.

The problem with those type of liquid dish fluids is that you on one hand are removing the dirt and grease, but you may be leaving behind some of these 'added' chemicals which will be left behind even after you rinse the car off. These are possible chemicals that might react adversely if you try to paint over them etc.

Now.. on the topic of the 2500 grit sand paper.. Well yes... initially a 2500 grit sand paper will remove some of the gloss of a top layer of paint. BUT... at some point the physical top layer of paint will reach a smoothness where the whole surface is at roughly one level. At that point it starts to shine and gloss up...

So if you can understand what I am trying to say.... is that all sanding will cut back the original gloss where the sanding is knocking back any rises in the surface. Imagine a mountain range where you are running a giant sand paper over it. At first you would scrape off the peaks of those mountains. And as you continue sanding with your giant sandpaper, you would be sanding away the middle of the mountains. With enough sanding, you would have sanded away all semblance of mountains and have leveled them all down to the level of their valleys.

Ok... so on a gigantic scale, that is what is happening microscopically with the paint on the car. Your initial wet sanding is knocking back the peaks. At that time you will see the gloss being knocked back...

But when you hit the valley level of the paint job your sanding will be now starting to polish that uniform surface.. and the shine and gloss returns. That is why you will eventually take the sandpaper up to the 3000 grit level... because it will be leaving even smaller and more minute scratches.

Let's face it. A lot of folks don't really grasp the magic of sand paper. We all know that it scrapes surfaces smooth... But what a lot of folks tend to skip over is that the various grits of sand paper go from very coarse to ultra ultra smooth. And no matter what grit you are using, they all scratch the surface they are being used on.

Naturally the coarser ( lower number ) grit leaves the largest scratches on the surface it is being used. 120 grit means there are 120 PARTICLES of scraping material per inch on that sand paper. 3000 grit means there are 3000 particles of scraping material per inch on that sand paper. No rocket science needed here to figure out that the particles on that 120 grit paper are physically 25 times LARGER then the particles on the 3000 grit paper. That means the 120 grit paper is leaving scratches that are 25 times larger then a 3000 grit paper.

Soooooooooo.... as we work on the paint jobs... and we go from low grit up to the high grit... we are knocking back the larger scratches and replacing them with smaller and smaller and smaller scratches.

The smaller the scratches left behind.... the shinier and glossier the surface we are sanding...

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