It's important to mention that this article is written with the assumption that the reader has a basic understanding of car detailing.
I received a call from Lucia, who requested my help in removing scratches from the bonnet of her Mercedes SL400. She explained that the scratches were a result of cats sleeping on the car during the day.
Lucia mentioned that the car belonged to her late husband, and that he took great pride in it. He would wash the car himself and never allowed anyone else to handle it. I could relate to his sentiment. It was evident that the car held a significant emotional value for Lucia, and I was determined to do my best to help her out.
Upon inspection, the scratches appeared to be quite deep, potentially penetrating the clear coat. Upon receiving permission from Lucia, I attempted the water test by pouring clean water over the scratches to determine if they were still visible or if they disappeared. To my relief, the scratches were not visible through the water, indicating that they could likely be buffed out.
Can you explain the purpose of the water test? Essentially, the water acts as a temporary replacement for the damaged clear coat and fills in any scratches. If the scratch disappears, it means that the damage is likely only in the clear coat. However, if the scratch is still visible, it suggests that the damage has gone beyond the clear coat and into the base colour and possibly the primer. Since these layers are not clear, the water will not be able to conceal the damage. While it's not a precise method, it can act as a helpful indicator.
Lucia opted to have the entire car detailed instead of just fixing the damaged paint on the bonnet, which was a smart decision. This allowed for a uniform shine and finish throughout the entire vehicle. Despite being well-maintained for its age and a testament to her late husband's care, the car exhibited typical signs of paint swirling. We agreed on a price for the job, and I began working on it.
I washed and dried the car before getting rid of any stuck-on debris from the paint. This is a crucial step before polishing. Nowadays, we mostly use foam buffing pads because they protect the original car finish. Original finishes usually have a slightly bumpy texture, and the foam pads conform to this texture, creating a consistent cut without flattening the paint. This prevents any dull or hazy spots in the finish. However, the foam pads also bend around tough spots on the paint, such as tar and tree sap, so it's important to remove these first.
Before using a clay bar, it's important to chemically remove any bonded contaminants. Autoglym's 'Tar & Adhesive Remover' is a great option for dissolving most things, while a good bleeding fallout remover can tackle iron fallout. I used Autoglym's 'Liquid Clay' for this job. For anything else stuck to the paint, a surface detailing clay bar is the way to go. Once the paint surface feels silky smooth to the touch, it's time to start buffing.
To start, I focused on the bad scratches on the car's bonnet. To fix them, I used a Flex rotary buffer along with a Menzerna red heavy cutting pad and Mezerna Super Heavy Cut 300 compound. Although it took several passes, the scratches were fairly easy to remove. It's crucial to use a dedicated panel wipe after each pass and inspect your work to ensure the best results. This is extremely important because the oils in the compound can temporarily cover up problems and give a false impression. However, Menzera compounds are filler-free and do not have this issue by design. To see the true finish, a good panel wipe should be used to quickly remove any grease from the paint. You can easily find 5-litre cans of panel wipe at most motor factor stores.
After resolving the main issue, I proceeded to polish the entire car. To accomplish this, I once again utilized the rotary polisher in conjunction with a heavy cutting pad. However, this time I opted for Menzera's Heavy Cut 400 compound, which is a modern hybrid compound that includes diminishing abrasives, allowing me to achieve both medium and refinement cuts. Unfortunately, because I was working on a dark-coloured car with a rotary polisher, I was aware that I wouldn't be able to achieve optimal refinement and would still need to remove any remaining holograms with a dual-action buffer.
In the final stage, I switched to a dual action buffer, specifically the Flex 3401 forced action buffer. I am impressed with this machine because it is a hybrid between the rotary and a true dual-action orbital. Additionally, it has the advantage of never stopping if I increase pressure, which allows me to achieve quicker results. I used a black Chemical Guys Quantum foam pad and Menerna's Super Finish Plus 3800 compound, which is an ultra-fine compound designed for both rotary and dual-action machines. It works exceptionally well after the Heavy 400 compound.
After completing the Super Finish Plus stage, I wiped down the panels and inspected the finish with a bright light. Luckily, it was a sunny day which allowed me to take the car out from under the temporary canopy for a final inspection. The finish was perfect, as expected from the ultra-fine 3800 compound that promises a "Show Car Finish", and that was how I spent my day detailing with Menzerna cutting compounds, check the gloss in the video below.
Autoglym Tar & Adhesive Remover
Autoglym Liquid Clay
Menzerna Products