Polishing a Car Body
Polishing a Car Body
One of the most common questions I get asked is about the shine seen on my completed cars, especially the most recent ones. So when I finished airbrushing the 2K clear on my Subaru BRZ, I decided to photograph the whole polishing procedure I follow and create this tutorial to help other modellers get a good deep shine on their builds too. Obviously, everyone has his own method and procedure to polish an airbrushed body, and I have tried several different methods myself, but over time I have adapted the one that works best for me... and the one listed below, is exactly it!
Please note that this procedure works best on 2K clear. It can be used on 1K clear, however be very cautious while sanding and polishing since 1K clear is softer than the 2K one. This all means that you'll run through the clear faster!
Planning for the polishing stage starts early for me! Once I airbrush the colour coat on the body, I immediately apply 2 mist coats of 2K clear to seal the colour off. When the clear becomes fully dry, I slightly wet sand this using a 2500-grit sand paper to remove the orange peel. This is done to minimise the orange peel amount once the next layers of clear are airbrushed
After that, I wash the body well and apply any required decals. Then, I airbrush two more mist coats of clear. I leave these mist coats to settle for around half an hour and then airbrush 3 wet coats of clear. If there are no decals, I airbrush the wet coats immediately. The picture above was taken a week after I airbrushed the wet coats. As you can see, it's already very shiny!
But on closer inspection, you can notice that there is a small amount of orange peel visible on the surface and while it was drying some dust fell into the fresh spray (visible next to the yellow arrows above). Time to remove these imperfections!
To remove the orange peel and any dust present on the surface, I slowly wet sand using 2000 & 2500-grit sand paper with soapy water. If the amount and depth of the orange peel is small, as in the case of this Subaru BRZ, I tend to skip the 2000 step and begin right away with the 2500-grit one. This will keep the very fine scratches on the surface to a minimum
Here's another look at the minimal orange peel and dust on the surface of the hood
First thing I do is cut the sand paper I'm going to use in small boxes, as seen above. Then I dip them inside the soapy water and slowly start sanding where the dust particles are. After a couple of seconds, I dry the sanding area using a tissue paper and check if the dust particles are gone. If yes, I move on to the next dust particle until all of them are removed
When I'm sure that all dust particles are removed, I continue to slowly sand off all the area. Once again, I constantly dry the area to check if any orange peel is still present. This is time consuming but very important as you don't want to sand through the clear, especially at the sharp edges. The hood above shows you a fully matt finish indicating all orange peel is gone
The picture above shows the difference between a well sanded area (bottom part of roof) and an area which has been sanded but still has orange peel (top roof part). As you can see, once you start sanding, the orange peel becomes very visible since the surrounding area gets matt and dull while the orange peel parts would still be shiny indicating more sanding is necessary
While you're drying the sanding area with a tissue or cloth to check for orange peel, it's important to rest the sand paper in an upright position as seen above. You may ask, what difference does it make? It may not, but I'm speaking from experience! On you work area, there may be all kind of dust or particles present. A wet sand paper piece will pick any small particles to it if placed upside down. And if those particles are hard enough, like iron filings from an earlier job, you'll end up with several deep scratches as soon as you start sanding again! Happened to me and I can assure you that this experience is not nice!
Once I'm happy with my orange peel free surface, I turn to my micro-mesh set of sanding sheets. I do have the whole range, up until 12000-grit, but I feel that sanding up to 4000-grit is enough since I'm going to continue polishing with the rotary tool. If you're going to keep polishing by hand, then I suggest you go up all the range to the 12000-grit sheet. In my case, after sanding with the 2500-grit sand paper, I keep polishing using the 3200, 3600 and finally the 4000-grit sheet
Picture above shows the hood after polishing with all the 3 sheets, once again with soapy water. This procedure is done to eliminate all the fine scratches left by the 2500-grit sanding. The finish on the hood can be seen slightly shinier, but still matt
The whole sanding procedure explained above was then carefully performed on all body pieces that required polishing. Once again while sanding, keep an eye for sharp edges as these can be easily sanded through. Now, time to take out the rotary tool!
These are the 2 types of buffer wheels I use. The one on the left is softer than the other and I use it for the final shine and finish. The other wheel is slightly harder and used for the first round of polishing with a coarse polishing compound
First thing I do is attach the harder buffer wheel to the rotary tool and once it's locked in place, I cover the locking nut (or chuck) with masking tape. This is done as a precaution in case the nut touches with the body. There's still the possibility that it might damage the body, but the damage is significantly reduced. As for speed, I set it to the minimum which is 5000 rpm on mine. It may sound like 5000 is too much, but it works great for me. Just remember to keep the pressure on the body to a minimum
Before starting to polish, it's very important to remember this crucial rule about the direction of the rotating wheel near the edges. In the picture above, you can see that I have marked the correct direction (green) the buffer wheel needs to turn near this edge. If it turns the opposite direction (marked red), you're risking lifting the paint from the edge while turning. This precaution is often skipped in other people's tutorials, and this is why I'm highlighting it as it's very important to follow
Same goes for the back side, where you need to have it turning in the right direction or else you're risking lifting the paint!
This should be applied with all the edges, even around the arches and at the bottom of the whole car. Always get the buffer wheel to turn in-line with the edge, not the opposite way. Here, I have highlighted the rotation next to the rear window
This is the first polishing compound I use! It's an oldie, but works great for me! For this stage, you can use any coarse polishing automotive compound you like. Just watch out for compounds intended for colour restoration, as these might be more thick than you require. The basic procedure here is to cover the area with the compound, and start buffing slowly the whole area
I began by polishing the rear section of the left side, to be able to show a comparison between a surface that was sanded with the 4000-grit sheet (front section) and how the shine turns out after polishing with the first polishing compound (rear section)
Here's a look at how the carbon roof turned out after polishing with the buffer wheel. It's already shiny, but on close inspection one can notice that there are still some fine scratches visible. These will be taken care of by the next stage, the fine polishing!
Finally, all parts were polished in the same procedure with this buffer wheel and coarse compound. Time for the next step!
With the coarse polishing complete, it's now time to carry out the fine polishing process. For this, I use AutoGlym Super Resin Polish and the fine buffer wheel shown earlier. Once again, after attaching the wheel, the locking nut was covered with tape
The procedure here is the same as before: cover the area with the compound and slowly move the wheel around the area with the rotary tool turning at a low speed. When you have sharp areas like I had with the BRZ front bumper above, be very careful how you handle the buffer wheel around that. The rotating wheel might easily get stuck to pointed areas and ruin your paint
Same polishing procedure was performed on all body parts and a deeper shine was achieved, as can be seen above
Here's a closer look at the finished hood! Much shinier & deeper finish than the clear we started off with, no?!!
All that remained at this stage was to give all the polished parts a good wash with soapy water, and then a rinse with just water!
And here's all the parts drying off naturally. You can opt to dry everything using compressed air through the airbrush too. If you choose this option, just be very careful that you don't get the airbrush tip too close to the body while spraying. You definitely don't want to make any unwanted damage after all the hard work getting the body to such a deep shine!
To finish off the polishing procedure, once the body is fully assembled and the car is finished, I take out my Carnauba Wax and slowly polish the spray with it. You have to extra careful here since the car is fully assembled and very fragile! You can opt to do it at an earlier stage, but I believe that wax gets removed from the body when handling the car with bare hands, so I prefer doing it once I don't need to handle it any more! The procedure here is to carefully apply the wax using a soft cotton cloth, leave it to dry and become matt, and carefully remove the haze with the cloth. You only need a small amount of wax on the cloth every time, so take your time and patience while waxing and you won't have any trouble with breakages or other mishaps!
Finally, once you clean the dried wax, you will notice that some panel lines have gone slightly white. This is obviously due to the wax getting into the panel lines. This is no big deal as dried wax becomes almost powder, so it's easily removed. To do this, I make use of a combination of flat brushes and slowly brush away all the wax from the panel lines and window trims
Finally, is it worth spending so much time doing this intense procedure? Well, both pictures above speak for themselves!
To finish off, this tutorial might take long to perform, maybe too long, but it's definitely worth every step once you see the final result. For the BRZ, this whole procedure took me almost 6 hours but I don't regret any of it since I'm very happy with the outcome. I have seen and followed many polishing methods throughout the years and finally made up my own procedure! And this one above, is exactly it... Enjoy modelling!