# Trouble painting and sanding a scrape



## aymen_a22 (Jun 30, 2013)

I have a scrape on my wing mirror where someone went by a little too close.

There are some deep scratches and some light ones so I removed the cover and washed and dried it.

Next I gave it a very light sand with 1500 wet and dry followed by a light brush of paint over the area making sure the deep scratches were now protruding the original paint.

I left this to dry and then wet sanded with 2000 grit until it was all level however there is a clear difference between the original paint and the new paint. I then used some Farecla G3 scratch removal paste and worked this into the area with a slight improvement.

I then used Autoglym paint renovator to try and improve the blend with another slight improvement.

I have subsequently put lacquer over the top of it and used the scratch removal paste again followed by a layer of wax.

As I said, when looking at the area there is a line between the original and the new paint.

What have I done wrong? The paint is metallic black on a 2008 Vauxhall Corsa.


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## steveo3002 (Jan 30, 2006)

scuff up the whole cover and rattle can it


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## aymen_a22 (Jun 30, 2013)

I didn't really want to repaint the whole mirror as I wanted to practice wet sanding to see how it would turn out.

In the future I will do this to larger panel scratches and obviously do not want the same thing to happen which is why I was wondering if there is anything I have missed or forgotten to do.


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## XRDAN (Feb 28, 2012)

it would be harder and take longer to repair scratches to a high standard using this method than it would to do a smart repair on the panel. however for stone chips it would be worth it. in my opinion of course:thumb:


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## squiggs (Oct 19, 2009)

As above :thumb:

If you sanded and polished the paint before lacquering you will have damaged the metallic particles in the paint.

Had you used that method on silver paint you would have seen it instantly lose it's reflective/shiny/silver qualities and it would have turned grey - on a metallic black it won't be as noticeable, but noticeable all the same.


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## PaulN (Jan 17, 2008)

You would have been better filling the scratch before touching it with wet and dry too. You have rounded the scratches making it harder to fill and flat back...


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## aymen_a22 (Jun 30, 2013)

Ok so metallic paint is not able to be sanded back then.

I will repaint the mirror but what should I do for future repairs on larger panels? 

Many people do not seem to lacquer stone chips, how does that work? Surely you need lacquer on there or does the polish and wax take its place?


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## XRDAN (Feb 28, 2012)

most touch up pots used for stone chips have the lacquer mixed in so its all in one- even for metalics:thumb: if its a two stage like the halfords ones then you will defo need the lacquer before you polish


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## aymen_a22 (Jun 30, 2013)

So I have a spray can from halfords, should I mix some colour with some lacquer in a pot and then apply this mixture?

If I were to do this to a large deep scratch would I then be able to flat it back and polish it up to improve the look? Or should I put some colour into the scratch and then put some clear on top which would protrude and then flat back the clear coat?


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## PaulN (Jan 17, 2008)

Ideally you put a good coat of paint in the scratch allow it to dry well as it will shrink, then apply again and finally build up with lacquer, and flat the lacquer back.


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## aymen_a22 (Jun 30, 2013)

I think that is the information I was looking for.

Would I need to do this with stone chips as well or should I mix colour and lacquer for those and just apply that mixture and then flat that back?


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## PaulN (Jan 17, 2008)

Id mix it together for stone chips, you could leave the lacquer all together if the chip was small.

The Stone chip repair thread by Breezy will be a great help.

http://www.detailingworld.co.uk/forum/showthread.php?t=20127&highlight=stone


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## aymen_a22 (Jun 30, 2013)

I thought that you had to lacquer metallic paint otherwise when you wet sand it the metallic particles get damaged and you lose the shine.


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## PaulN (Jan 17, 2008)

aymen_a22 said:


> I thought that you had to lacquer metallic paint otherwise when you wet sand it the metallic particles get damaged and you lose the shine.


Small chips you wont tell. Id pratice on a few stone chips before hitting larger scratches.


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## aymen_a22 (Jun 30, 2013)

Ok thank you for that advice, I'm slightly worried about ruining my bonnet but hopefully it will all go ok. 

I will probably be back soon with more problems.


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## aymen_a22 (Jun 30, 2013)

I think I must have just put all the layers on too soon then really.

I did some work on another mirror which required filling and it has come out so badly. Cracked all over the place.

Need to do it again but its a little cold at the moment.


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## mr paint (Jul 11, 2009)

You first of all need to go to a paint supplier and get mixed paint /base coat 



You cant really fill a scratch with paint tbh same as you cant fill it with filler paint will always shrink especially if built up ...paint is measured in microns and still shrinks 

scratches are into mm Defo going to sink . 


The colour you are putting down is base coat this will dry to a matte finish THIS MUST BE coated with clear coat !

You do Not sand base coat UNLESS you have defects in it then you MUST apply one last coat ...before your clear coat .



If doing a scratch on a car we would :

120G the scratch down to metal 

240g feather edges 

320g surrounding 

e-prime bare metal 
2k prime in close colour to base coat 

flatten primer once cured with 400 then 600 colour dependent (guide coated)

de grease 

apply base coat (colour) over primer 

apply base over primer and blending out to existing paint 

let flash for x amount of time 


apply 3 coats of clear allowing 15-20 mins between coats 


walk away 


Tommy


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## aymen_a22 (Jun 30, 2013)

Great advice, thanks very much.


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## craigeh123 (Dec 26, 2011)

Tommy why when use anything as coarse as 320 does it show through the paint ?


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## squiggs (Oct 19, 2009)

craigeh123 said:


> Tommy why when use anything as coarse as 320 does it show through the paint ?


Anything coarser than 320 simply won't leave a smooth enough surface for the paint to sit flat on and as paint has no filling properties the sanding marks can show through. 
How far you need to go down through the grades will depend on what type of paint you're using (solvent, cellulose, waterbased, etc,) but 320 is minimum. 
I use waterbased paint which is very unforgiving so I take it at least a stage further on my repairs - I flat to 320 then prime, then I take out any nibs with 320 and then 400. At this stage if I go through the primer anywhere I'll re-prime and repeat de-nibbing and then 400 again and finally I'll very quickly go over with 1500 before applying paint.
It's never going to be a satisfactory job if you apply your paint and see the sanding marks - and on occasion it can be even more soul destroying as the sanding marks won't show after painting but then show once it's been lacquered  
All in all I work on the principle that it's better to be safe than sorry


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## craigeh123 (Dec 26, 2011)

I finished up on about 600 before primer last time then used 1500 before paint seemed to work well . Just everytime i read up people finish on 320 before primer but ive always seen marks when i do . That said in only using 1k


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## CD Cornwall (Aug 12, 2010)

craigeh123 said:


> I finished up on about 600 before primer last time then used 1500 before paint seemed to work well . Just everytime i read up people finish on 320 before primer but ive always seen marks when i do . That said in only using 1k


The only reason marks would be seen through 320 before primer is that the preparation was poor. When sanding, each grade has to at least get to the bottom of the scratches of the previous grade, otherwise, the next finer grade will only be sanding the surface above the scratches. You can prime over 180 without issues if you have prepared the surface correctly and use a quality primer.

Cheers
David


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## craigeh123 (Dec 26, 2011)

Thing is i know all this i used to mirror polish metal and never had trouble with that . I guess in being a little impatient moving up the grades


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