When the paint guys on Overhaulin' or Speed Is The New Black need to get their paintwork to show car standards, they use a technique called "cut 'n buff." It's a labor intensive process of smoothing out the top layer of paint (typically clearcoat) in order to remove the lumps, bumps and imperfections to leave a smooth surface, which is then machine-buffed to a high gloss, which the eye sees as a mirror finish. The "cut" portion is done with very fine grades of wet-sanding paper. It's a learned skill — too little and the finish isn't the best it could be, too much and you've sanded through the clear into the color or primer. The "buff" is accomplished with machine buffing using specific grades of cutting compounds, followed by machine polishing.
On my projects my goal is always to bring the original paintwork up to the highest level I can. Part of this might involve touching up nicks and scratches, but the real magic can be achieved with a process similar to cut 'n buff, which I learned as "color sanding." The concept is the same, but the idea with color sanding is to remove just enough damaged paint to get down through the decades of scuffs, surface scratches and environmental damage — sun, pollution, petrified bugs, whatever.
On my projects my goal is always to bring the original paintwork up to the highest level I can. Part of this might involve touching up nicks and scratches, but the real magic can be achieved with a process similar to cut 'n buff, which I learned as "color sanding." The concept is the same, but the idea with color sanding is to remove just enough damaged paint to get down through the decades of scuffs, surface scratches and environmental damage — sun, pollution, petrified bugs, whatever.
For the sanding portion of the process I use the finest grit I can get away with, working my way to a final sanding with 5000-grit. 3M provides wet-sanding paper and sponges up to 5000-grit. I begin with the 2000 or 3000 and go rougher only when necessary.
After cleaning the part to be color sanded, I fill a small, clean pail with fresh water with a few drops of dish soap added. With frequent dippings into the water, I gently wet-sand the entire painted area then wipe dry with a clean cloth to check my progress. A deeper scuff may require a stronger grit, remembering that the goal is to achieve the greatest effect but without sanding through the clear coat. This is especially true with pearl paints because the pearl coats are applied on top of the color and sanding away the pearl changes the hue of the finish color. And, I have to accept that some "patina" just can't be sanded away, but in any event the piece as a whole will end up glossier with more vibrant color — hence the term "color sanding."
Practicing on an old part will give a good feel to how much sanding you can get away with before damaging the part with excessive sanding.
Below are a couple of examples of common fairing scuffs that will come right out with a gentle sanding.
(click on images to enlarge)
After cleaning the part to be color sanded, I fill a small, clean pail with fresh water with a few drops of dish soap added. With frequent dippings into the water, I gently wet-sand the entire painted area then wipe dry with a clean cloth to check my progress. A deeper scuff may require a stronger grit, remembering that the goal is to achieve the greatest effect but without sanding through the clear coat. This is especially true with pearl paints because the pearl coats are applied on top of the color and sanding away the pearl changes the hue of the finish color. And, I have to accept that some "patina" just can't be sanded away, but in any event the piece as a whole will end up glossier with more vibrant color — hence the term "color sanding."
Practicing on an old part will give a good feel to how much sanding you can get away with before damaging the part with excessive sanding.
Below are a couple of examples of common fairing scuffs that will come right out with a gentle sanding.
(click on images to enlarge)
(Below) This process works just as well on plastic fixtures like tail light, turn signal and headlight lenses. Here I'm using 1000-grit paper on a tail light lens, which I will follow up with 1500, 3000 and 5000. Yeah, it's a lot of sanding.
(Below) For the buffing portion of this process I use my Griot's Garage small orbital polisher with 4-inch buffing pads. I have a selection of compounds but my go-to is Meguiar's Mirror Glaze #83, followed by Meguiar's Ultimate Compound. I finish up with a quality wax, hand applied. This is yet another behind-the-curtain example of the hours of work required to bring these machines back to their best.
(Below) Some of the finished product.
RSS Feed