Mercedes-Benz has been manufacturing the SL since 1954. Now in its sixth generation, the grand tourer’s popularity shows no sign of diminishing. Revealed at the January 2012 North American International Auto Show, the new SL (R231) now features an almost entirely aluminium body shell, making it significantly lighter than its predecessor – around 110kg lighter – in spite of being 57mm wider and 50mm longer. Other improvements over the previous model includes a stiffer underbody, increasing the car’s torsional rigidity by a touch more than 20%, ensuring the SL 500 (R231) delivers a truly dynamic performance. Handy too, as the SL 500 is powered by a V8 bi-turbo engine capable of producing 429bhp and 516lb/ft. of torque propelling car and occupants from 0-62mph in just 4.6 seconds.
The interior is as plush and as refined as you would expect from a quality marque such as Mercedes, with plump, comfortable leather, modern metal trim and instruments reminiscent of an aeroplane’s cockpit. Whilst it’s short on boot space (mostly taken up by the folding roof) and unapologetically designed for only two people, the SL 500 is still one of THE grand tourer’s other marques look to better.
Keen to have the SL 500’s appearance restored to a high standard, the owner added Leather, ClearVision Glass and Alloy Wheel Protection options to the list of detailing requirements. First though, the wheels would need to be fully refurbished to factory standard. Two of the rims required welding to repair a couple of small cracks to guarantee a perfect finish and one required straightening following a recent pothole collision.
Decontamination began with the wheels and wheel arches. As areas most likely to attract and trap dirt and debris, cleaning loose debris will help prevent additional dirt transferring to the bodywork. A trolley jack was used to raise each corner of the SL 500, in turn, to increase the gap between the bodywork and the wheel so the arch liners could be thoroughly cleaned.
The area was jet washed to remove loose dirt before being degreased using Bilt-Hamber Surfex HD, a water-based cleaner that eliminates oil and diesel splatters.
The wheels and arches were cleaned using UF Safe Wheel Cleaner and Wheel Woolies, long-handled soft-bristled brushes that fit through the alloy wheel spokes to clean the rear of the rim.
The bodywork of the SL 500 was treated for brake dust contamination commonly found along the sills and behind the wheel arches. UF Iron + Fallout Remover was sprayed on and allowed to dwell before being rinsed away. Then, Ultimate Snow Foam was applied and allowed to dwell for several minutes, the thick foam lifting larger particles of dirt and grit from the panels and encapsulating the contamination within the foam. The contamination was rinsed away before the SL 500 was carefully washed, using two buckets with Grit Guards to keep wash solution separate from rinse solution. The wash mitt is dunked into the Wash Bucket, a section of the vehicle washed and the mitt rinsed in the Rinse Bucket. The mitt is brushed against the Grit Guard releasing dirt from the pile that then settles to the bottom of the bucket. The mitt is wrung out before being loaded with wash solution again and the process repeated until the car is clean. This process keeps the dirty rinse water separate from the clean wash water and helps prevent the reintroduction of dirt onto the paintwork; a common cause of wash swirls in paintwork.
After rinsing, certain areas such as the front grille, bonnet and along the sills still felt rough to the touch so, a second application of Ultimate Snow Foam was used as a lubricant for a clay bar to remove the stubbornly bonded contamination; in this instance, overspray and road tar.
The SL 500 was then cleaned once more with Ultimate Snow Foam before being given a final rinse. The car was brought into the studio and placed on a hydraulic ramp where the wheels removed, checked and sent for refurbishing. The SL 500 was dried using a BigBoi BlowR Pro touchless car dryer to force all droplets of water out from areas that would naturally trap and hold on to them. The condition of the paintwork was then closely inspected under high-intensity lighting and areas of concern noted on a Vehicle Appraisal Sheet for reference during machine polishing.
Multiple paint depth readings were taken over each panel and the paint found to be of average and uniform thickness. After the thorough assessment, the paintwork was determined to be particularly hard.
Typically German clear coat is hard, but on this SL 500 it was even harder than normal. Whilst this can be good news for owners of these marques, any machine polishing correctional work will be more challenging for the detailer. – Dean Foster, Detailer, UF Studio
For the first machine polishing stage, a RUPES LHR 15ES was used with a Meguiar’s Microfibre Cutting Disc, the combination producing a powerful cutting action whilst limiting the amount of micro marring and therefore the amount of refining that would be required later. Koch-Chemie Heavy Cut H8.02 compound was used as it has high lubricity and can therefore be worked for long periods of time, allowing the diminishing abrasives to fully break down. Due to the hardness of the finish, up to six passes were required to achieve the desired results. Gradually, the holograms and hazing were eliminated and the clarity of the paint restored.
For refining, Menzerna Medium Cut Polish 2400 with a RUPES Yellow Polishing Pad were used to bring the finish up to a high blemish-free shine.
The paintwork now enhanced, the panels were treated with Gtechniq Panel Wipe to ensure all traces of polish residue and clear coat dust were removed from the surfaces, preparing them for the protective coating. In this instance, the owner had selected a service upgrade to Pro+, choosing Gtechniq’s flagship coating, Crystal Serum Ultra (CS Ultra) as the primary coating, finished with a layer of EXO v4 Ultra Durable Hydrophobic Coating for additional slickness and shine. This combination is known as CS Ultra Black.
Gtechniq CS Ultra is an innovative coating in that although it is applied as a single stage, it cures as two distinct layers. The lower layer cures to a hardness of around 7H (on the pencil hardness scale) providing a tough but flexible layer. The upper layer cures to around 10H to provide significant protection from wash swirls. Engineered to contain a larger and a smaller molecule, the coating layers settle together providing a fully interlocked interface for comprehensive paintwork protection. Treated surfaces are slicker and therefore easier to maintain as water, waterborne dirt, grime, and industrial and environmental contamination are unable to adhere effectively. CS Ultra must be applied in a specific manner, working a small area at a time, and buffed immediately to ensure optical clarity. In addition, ambient air temperature and humidity must be within set parameters. Available only as a service through Gtechniq trained and approved detailers, Provided forward maintenance wash regimes are adhered to, UF Studio guarantees the performance of the coating for up to 36,000 miles
After the car had been coated with CS Ultra, it was allowed to cure for an hour before a top coat of EXO v4 was applied. This adds an extra layer of hydrophobicity and slickness, making the paintwork glow.
Whilst EXO and CS Ultra were curing, attention turned to the interior. The cream leather seats were in good condition and to ensure they remained that way, they were cleaned and then protected. First, Colourlock Mild Leather Cleaner was applied and worked into the material with a Leather Brush, lifting dirt and oils out of the leather grain. After wiping dry with a soft microfibre, the leather was protected with Leather Shield. This spray-on protectant adds a hydrophobic layer that helps prevent the leather becoming stained from accidental spillages and from dye transfer from dark coloured materials or jeans. Leather Shield also contains UV inhibitors, helping to prevent the leather from becoming dry and brittle from exposure to the sun. Treated leather is supple and feels luxurious to the touch.
The windows were treated with Gtechniq G1 ClearVision Smart Glass, a hydrophobic coating that repels rainwater, forcing droplets to roll into beads on contact with the surface and allowing them to be easily blown away, even when driving at relatively low speeds.
This keeps the windscreen clearer when driving through rain, reducing eyestrain and fatigue for the driver. The hydrophobic action also prevents snow and ice from adhering to the treated surface, making early starts easier and quicker on frosty mornings.
The interior carpets were vacuumed to remove loose dirt and debris. The driver’s foot well, a ‘high traffic’ area, was noticeably darker than on the passenger’s side. The carpet was sprayed with an all-purpose cleaner and agitated with a detailing brush. The carpet was steamed to lift dirt out of the fibres to improve the appearance. Once dry, the carpets were protected with Gtechniq I1 AB Smart Fabric, a nanotechnology based hydrophobic spray-on coating that protects each fibre individually, protecting both the appearance and the texture of the material. The ‘AB’ represents the antibacterial function contained within the formulation. This helps to prevent the growth of bacteria; a key source of unwanted smells.
The wheels had been sent for factory standard refurbishment and once returned were treated with Panel Wipe to remove any unwanted residues before Gtechniq C5 Alloy Wheel Armour was applied front and back.
This hydrophobic, oleophobic ceramic coating provides a tough barrier that repels water, dirt, and oils and inhibits the build-up of brake dust. Virtually impervious to extremes of pH and resistant to high temperatures, C5 will not wash or burn off. Treated wheels remain cleaner for longer and the protective properties last for up to one year. To accelerate the curing process, infrared lamps were used.
The wheels were re-fitted with attention paid to factory torque settings.
The tyres were coated with Gtechniq T2 Tyre Dressing to provide a natural satin sheen that enhanced the look of the newly repainted, silver, diamond cut wheels.
The final result was nothing short of outstanding, truly a transformation for the clarity of the paintwork. With all surfaces fully protected, this SL 500 will remain top of the class for years to come!
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