Scale Auto Replica's

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Preparing, painting & Wet Sanding Car Bodies

One thing that lets down a car model is the paintwork, as lets face it, it's the first thing you see when looking at any model, the detail inside and under the bonnet can be first class, but if the paintwork isn't up to scratch, (No pun intended), the model will often get overlooked, over the years my modelling has improved immensely, and not so long ago I bought myself a polishing kit manufactured by Micro Mesh, they are now available here in the U.K, and well worth getting.
Now with any paint work, it really starts in the preparation of the body and body parts, first off wash all the parts in warm soapy water, for this I simply use ordanary washing up liquid, and give the parts a good scrub with a medium toothbrush to remove any mold release agent used in the manufacturing process in plastic molding.
Once all the parts are dry, check all parts for mold lines, flash,ejector pin marks and any other defects, for ejector pin marks I use a 2 part epoxy putty, or Bondo as it is more commonly called, flash and mold lines and flash can be removed using a medium sanding stick, once all work has been done, another wash in warm soapy water will remove any dust and grease left on the plastic from your fingers.

Once the body has had all the defects removed and been washed and left to dry, the next job is to get the body in primer, now if your using model enamel and acrylic's you could skip this step, but I really recommend using a good plastic primer, not only does it protect the body from some of the hotter lacquer paints, it also gives the paint something to bite onto, and trust me, you will end up with a much better looking paint job, for this step I use a good acrylic plastic primer, once this has dried it will need sanding, if you skip the sanding, you will never get the topcoat looking it's best, as even if you can't see any problems with the primer coat, it will still have a rough surface, even if it looks smooth, it won't be, use a 3600 grade flatting paper out of the polishing kit I mentioned at the beginning of the article, although you can buy the flatting papers separately if you don't want to buy the complete polishing kit, but I really recommend doing so, if you manage to sand through the primer coat which is easily done, put on another coat of primer and again leave to dry for a couple of hours.

Once the primer coat has dried out, you need to sand it smooth, I use a 3600 grade paper used wet, once the primer coat is smooth, leave to dry, before you start with the colour coats, go over the body with some panel wipe on a lint free cloth, if you can't find panel wipe,which should be available from any automotive paint store, use 70% isopropyl alcohol, and go over the parts to be painted with a tack cloth, again these should be available at any automotive paint store or body repair shop.
I use cellulose or acrylic lacquer to spray my bodyshells, applied using an airbrush, other modellers get good results using aerosols, but you will always get better results using an airbrush as the spray pattern is finer and the paint atomises much better, but what ever method you use to put the paint onto your models, the wet sanding method is the same, but if your using an airbrush you need to get the paint and thinners mixed correctly otherwise the paint will either be too thin and will cause runs in the paint and a very patchy finish, too think a mix and the paint will probably not spray through the airbrush or if it does it will be too think and will need a lot more sanding and polishing to get the finish looking right, I start with a 50:50 mix of paint to thinners and may well go up to a 70:30 mix, and use a pressure of around 20 p.s.i on the compressor, again depending on the make and type of airbrush, you may need more or less pressure, once you have found the best pressure setting for the airbrush you are using, make a note of it, and use that pressure for all your paintwork.

Looking at the body in the photo above, plenty of modellers would be happy just to leave it like that, but with a little more work, it can be made to look so much better, and if you have a polishing kit, or at least a sheet of 3600, 4000, and 6000 grade flatting paper and some cutting compound and some regular car polish, it will cost you nothing more than a little time, although personally I do prefer the polishing kits, mainly because they supply in their kits all the products you will need, most of them supply flatting papers as far as 12,000 grit, some cutting compound and a soft flannel cloth.

To start the process, get a small plastic container and fill it with warm water and add a few drops of regular washing up liquid, and put the sheet of flatting paper in the water, now get the flatting paper and start gently flating the panels on the model, it's best to work slowly and do one panel at a time, if you were to look at the paint under a microscope you would see what looks like a cross section of hills and valleys, now what you are doing with the wet sanding is to actually sand off the hills and bring the surface of the paint level with the base of the valleys, so if you work slowly and stop once the paint surface is level with no signs of low or high spots, this is the time to stop the sanding process 

The photo on the left show the door after being wet sanded and polished, first using the polishing compound that came with the polishing kit, followed by Poorboys SSR2, a medium cutting polish used for full size cars to remove light scratches and swirl marks, followed by some Meguires polish and then a couple of coats of carnauba wax.

The same treatment was given to the front luggage and engine compartment covers, the photo's below show the front luggage compartment, on the left is how the paint was when it was sprayed, the middle photo is the same parts after being wet sanded and polished, the photo on the right is a photo of the door showing the reflection of a piece of paper, you can clearly read the writing in the reflection in the paint, you won't get this on a body that hasn't been wet sanded and polished, I know which one I prefer .....

Before polishing

After Polishing

Wet Sanded & Polished