# Quick guide to water sanding a panel and polishing it



## Rotary (May 15, 2011)

Here again.

I decided to do another guide to water sanding.

This time i used a proper P2000 grit water sanding paper with a cork backing to remove some deeper scratches from the Subarus rear quarter.

I was also testing the Prestas Chroma Polish to see how much you can really do with one single product on a black metallic like ours.

First off, start by cleaning your panel. I suggest using a paint degreaser such as Dupont or PPG. You can get those from any paint selling shop.

The reason for this cleaning is that these types of degreasers really go deep and remove ALL wax and debits from the surface. They are safe to use on all paints, but will kill a normal spray paint for sure.

After this, go on and sand the area where the scratches are. Go gently, and clean the surface from time to time, to see how you are doing.

I would suggest going on top of the P2000 with alot higher grit papers to get the compounding done easier, but my test was to sand with P2000 and then use a single compound to finish.

Here is the panel after sanding.



















After this step, i degresed the panel again carefully.

I decided to use a soft black pad with my rotary, and go on as the bottle says, rub in at low speed, then polish up at around 2000rpm.

I noticed that i had to do alot of work to get rid of the sanding marks with the soft pad.

I actually had to swap to a medium pad to finish the job, and them come back with a soft pad to finish the panel.

This is the compound.










Spreading is very good when the revs and the pad are both ok.



















This is the MIRKA black pad (finishing)










Here you can see that the soft pad has left some marks to the lower part of the panel. It is just too fine for the compound to attack the sanding marks.










Here is the finished panel waiting for the hologram removal with the 3M Blue compound and Blue pad.

There actually were no holograms, but i do it on every dark colour to be on the safe side.


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## salsheikh (Jul 5, 2010)

nice write up dude, jobs looking good too


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## spursfan (Aug 4, 2009)

No PTG? any guide should include what to do if scratches are that deep and that should include the use of a PTG.
for more info on this subject i would take a look at Kelly Celtics posts, his knowledge on this field is second to none.

Kev


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## CraigQQ (Jan 20, 2011)

have you ever tried p1? 

i find it much safer.. using a compounding pad to remove sanding marks, then follow up with a polishing pad, then you can refine with 3m blue on blue combo

with its low working speed, the paint doesnt get so hot! (with a 3m yellow pad.. i can work the paint for 3-5 minutes, and its not even warm to the touch!!)
works from 900-1200rpm. (gtechniq say 900, but thats probably with the 200mm psystem pads, 1000-1200 works well with 150mm pads)
2000rpm is quite high to be compounding.. bigger risk of paint burn ect.


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## james_death (Aug 9, 2010)

Nice work...:thumb:


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## Clark @ PB (Mar 1, 2006)

CraigQQ said:


> have you ever tried p1?
> 
> i find it much safer.. using a compounding pad to remove sanding marks, then follow up with a polishing pad, then you can refine with 3m blue on blue combo
> 
> ...


2000 rpm's isn't a big deal on larger panels. You'll find quite alot of experienced detailers go up and over this when they need to when doing serious defect removal.


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## Rotary (May 15, 2011)

spursfan said:


> No PTG? any guide should include what to do if scratches are that deep and that should include the use of a PTG.
> for more info on this subject i would take a look at Kelly Celtics posts, his knowledge on this field is second to none.
> 
> Kev


PTG?

sorry i don't know the term.

I can give every info needed if I understand all the terms


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## Rotary (May 15, 2011)

Clark @ PB said:


> 2000 rpm's isn't a big deal on larger panels. You'll find quite alot of experienced detailers go up and over this when they need to when doing serious defect removal.


Yep, actually, when working at "too" low speeds, makes the compounds scratch more easilly.

All of the Presta products work on higher speeds than most.

The thing here was to show how easy it is to work on the panel with minimum effort and only few stages.

If scratches are very deep, then there is always the risk of going trough the clear.


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## The Cueball (Feb 8, 2007)

Rotary said:


> PTG?
> 
> sorry i don't know the term.
> 
> I can give every info needed if I understand all the terms


A machine that gives you an idea of how much paint and clearcoat is on the car so that you don't damage it...

Something like this:

http://www.detailingworld.co.uk/forum/showthread.php?t=169842&highlight=paint+detective

I know you don't use them, as per your last guide when I mentioned it, but there are lots of newbies, so always better to be safe than sorry!

:thumb:


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## Rotary (May 15, 2011)

The Cueball said:


> A machine that gives you an idea of how much paint and clearcoat is on the car so that you don't damage it...
> 
> Something like this:
> 
> ...


That is true. But people have to remember that the readings don't really give you the thickness of the clear coat. Atleast those meters i have used in my profession.

Those that i have used, measure the total thickness, and that doesn't honestly tell too much when polishing a cleared surface, as the thickness of the clear will vary, as does the paint beneath it.

That's why iqhave always told people to learn to read the clear coated surface by eye.

On 1K (so called acrylic, no clear coat on top) you can use the thickness gauge, but again, if there is a any filler beneath the paint, the reading will rise and indicate a false thickness for the paint it self. Again, if the paint is painted over the old paint, the reading will be lower.....BUT here's the catch, i can easily paint lets say 3 coats of paint, making the gauge read high thickness. It is true reading, but some professional detailer etc, would say that it has a thick filler beneath the paint, which in this case would be a mistake.

What i can say is, that DO use the gauges if you are not sure, or are learning the techniques, but don't trust the readings blindly.

In most cases, you can easily see a repainted surface, you can even see how much there is to play with.

If you clean the surface, clay it, and maybe use a light polish to reveal the surface, then you can see how much there is paint to work on.

I just had a 2001 BMW M3 here to work on, and when i saw the bonnet, i could easily say to the owner, that the bonnet won't be 100%

You can see some sanding marks under the paint (had a clear coat), and the bonnets paint was not shiny from the spray gun, revealing that there is not much of clear to get rid of.

One of the best ways to see if a scratch is too deep to polish, is to carefully look at it in good light, see if the colour of the scratch is light, meaning that it has wen't through the paint revealing primer. Also, you your nail sticks to the scratch alot, then you must be careful, because then it goes very deep to the paint.

I will try to make you guys some photos next time i'm on a car that has some ****** problems. Maybe it helps more.


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