Mercedes SL500 – Correction

August 1st, 2010 by Paul

Right from the very start we knew we were in for a tough time with this one. A few years of automatic car wash abuse and time spent ploughing through hedgerows by the previous owner had left this magnificent motor looking dull and lifeless. The brief was simple, get the car looking as good as possible – not being scared of a challenge we cracked on and this is how we did it…

Dull, lifeless and lacking gloss…
SL 500

…to glossy, sharp and reflective
SL 500

The day started well. The car was dropped off to us the previous evening and the early morning sun was welcome as the car was washed, clayed and dried. After a few hours of pulling off the contamination it was clear that we were going to be up against it. Many years of automatic car washes had left the car very badly swirled and the passenger side had seen a lot of country lane hedges – clear even without the inspection lighting that the scratches to the side sections were deep.

swirling and marring
SL 500

SL 500

some very deep scratches to deal with
SL 500

SL 500

some deep scratches on the mirrors and doors were a dead giveaway

SL 500

SL 500

Out with the paint thickness gauge – a little low for a Mercedes
SL 500

and the stone chip free bonnet gave away the fact that it had seen some paint before

SL 500

With this in mind, we taped up a section of the boot ready to test and set the Chicago rotary to work with Menzerna 203s

In normal daylight the correction was obvious – the colour restored and the light swirling removed.
SL 500

lighting it up with the LED torch showed a different story though
SL 500

deep scratches and heavy swirling remained
SL 500

Getting there, but still not great! Out with the powergloss
SL 500

two hits with powergloss and we were getting somewhere
SL 500

But then it all came to and end. With the scratches and swirls still remaining a rethink was required. The bonnet was corrected with 203s (clearcoat was much softer than the rest of the car) but the other areas would require something with a bit more cut.

A few phone calls later and a bottle of 3M Fast Cut was ordered and ready for collection in the morning. With only two days remaining I sent an email to the client – we would need the car for four instead of the three days. We weren’t going to cut corners and the magic 95% correction mark was still in sight. With the Fast Cut ordered it was time to down tools and concentrate on the other areas of the car for the rest of the day before admitting defeat and packing up for the day.

Test section on the door – correcting well but those tougher marks were proving hard to remove.
SL 500

Day two soon came around and armed with a bottle of fast cut we set to work on the door. Here you can see the difference as well as those deep scratches – we had to be careful here as the amount of paint overall was very low so we had to proceed with caution. After every set with the polisher it had to be wiped down with a strong IPA solution (60:40 compared to the normal 50:50 due to the filling properties of the Fast Cut). This revealed the scratches that would still take two and in some cases three hits before we hit the 95% correction we were aiming for with such low paint. Any further and we would have had to wet sand and possibly compromise the amount of clearcoat on the car – something that we weren’t prepared to do.

SL 500

The correction we were aiming for – still needing refining
SL 500

Some of the remaining scratches – hidden with the LED but showing up under the halogens.
SL 500

With the benchmark set high it was time to finish the compounding stage – and 10 hours later we had nearly finished. With the ambient light fading, arms aching and seeing swirls with our eyes shut it was time to call it a day. The car was given a final IPA wipedown and we packed up.

Next day it was time for the polishing and refining stage. With the car rinsed down it it was clear the that the heavy compounding inflicts marring of its own that has to be polished and then finished down to ensure the clearcoat is free from tight swirling that is put in from heavy the heavy cutting compound. The whole car was finished and refined with Menzerna 203s and 3M Ultrafina.

The whole day was spent polishing, checking, polishing and refining to ensure it would look the best it possibly could.

And how it looked once corrected, glazed and topped off with a premium “vintage” carnauba wax.

It went from looking like this….
SL 500

To this…
SL 500

SL 500

SL 500

SL 500

SL 500

SL 500

SL 500

SL 500

SL 500

All in all a very hard but very satisfying job. We hope you enjoyed the write up and would love to hear your comments.

Leave a Reply