There are various methods of dealing with a finish, depending on who you ask. Different methods work well for different people. The following is briefly my method;
The process to a good finish starts with the initial body work preperations.
- I scuff up the bare plastic body with 600 or 800 grit sand paper and remove any mold seperation lines.
- I scribe all panel lines nice and deep. Scriber slips are repaired with Gunze Mr Surfacer 1000 or 1500 (a brushable primer that feathers really well).
- Any low spots or sink marks are filled with putty.
- Then I block sand the entire body. To do this I cut smallish pieces of 800 or 1000 grit sand paper and wrap them over the end of a vinyl drafting eraser (the sanding block), then wet sand the entire body, paying particular attention to door & trunk lid shut lines and panel gaps. Panel gaps often have a slightly raised edge right at the gap. It is almost imperceptable, but when polishing the paint later on you can burn through easily if it is not removed. Careful wet block sanding will get rid of it.
- Wash body thoroughly under warm running water and mild hand soap or basic Dawn dish soap (ensure no lanolin, silicones, or moisturisers are in the soap as these can cause paint problems)
- I then mask any fine engraved body details (such as badges, etc) that are easily buried under primer, and lay down a medium coat of primer. When dry I check for imperfections, mold lines that got missed, and ensure filled sink marks and panel scriber slips are invisible. If there are issues such as body putty that didn't feather out well, apply Mr Surfacer and wet sand with 1000 or 1500 grit until its sorted. (Note: Primer can be applied earlier in the process, if it suits you).
- When happy with the body work, sand the entire body lightly with fine (1000-1500) grit paper. This can be done dry. Apply one last, light coat of primer. When dry, lightly sand with 1500 grit paper.
- When you are happy the body, wash it again, blot off excess water with a lint free cloth, and let it air dry completely.
- Apply paint. When airbrushing, first apply paint to raised edges and curves to reduce the chances of burning through the paint when polishing. Also, paint the panel gaps, and tricky areas such as scoop inlets, curved under lower body contours, etc before laying down the overall body paint. Apply a couple mist coats and let flash off. Apply one or two good colour coats and let flash well. Then apply your wet coat.
- I like to let paint cure really well before proceeding with polishing. Because it suits my style, I put the body in the dehydrator for several days to a couple of weeks. This is longer than necessary, but I'm working on other parts of the kit, so why not. Besides, I often paint with enamels, which take a long time to gas out. If there is any masking tape on the body, remove it before putting the body in the dehydrator.
- If there is orange peel in the paint or junk such as dust, lint, pet hair or wayward critters, remove it with a semi coarse sanding pad. You want to use the finest grit you can get away with to save work down the road, but it needs to be coarse enough to flatten the high spots (I will try to start with about 4000 grit, but if the paint needs a lot of work I will start with 3200, or even 2500, but that's pretty coarse). This will be done with a sanding pad (such as MicroMesh) or using the sanding block. Using a pad or block is necessary until the high sports are flatten down, otherwise you will simply end up with shiny orange peel or critters. All of this colour sanding is done wet. Go easy and carefully. It is helpful to put a thin strip of masking tape on raised edges to avoid burning through the paint. Raised edges are easily done with finer abraisives later on.
- Some builders will clear coat following the curing of the paint (or even before it is fully cured). Others will clear at this point in the process. Personally, I rarely apply clear coats unless painting with metallic paints. Because I won't be doing my final polishing on a clear coat, I try to ensure I get enough paint on during the paint application. Also, many builders apply decals and foiling before clear coating, so if you are one of them, now is the time. Personally, for maximum realism, I apply both after clear coating (if and when I clear coat) except decals that represent actual painted graphics.
- Carrying on, your model is either cleared now, or it isn't. Either way, I would now use a 4000 or 6000 grit polishing pad, always used wet. Do the whole body thououghly and check your work often. Check to see if the scratch marks from the previous grit pad are being removed. In most cases I will follow on with 8000 and 12000 grit polishing pads, again, used wet.
- I then move on to Tamiya polishes. In many cases you can stop with the polishing pads at 4000 or 6000 and move on to Tamiya Coarse polish. If I go right to the 12000 grit pad, I follow on with Tamiya Fine polish. Becareful as this stuff can remove a lot of paint layer. I will do two runs of the Fine polish, wash the body, then move onto two rubs with the Finish polish (Tamiya polishes are awesome on kit glass, too).
- Thoroughly wash the body.
- Apply foil now. Apply any decals. Attach any PE, or anything else that will be adhered to the body paint.
- Finish off with a couple coats of Tamiya wax (This stuff works great on kit glass, too). Keep in mind that once wax has been applied, nothing is going to stick to the body work. Also, the waxed body will be quite slippery.
Well, that's my process, and the materials I use. Hopefully I haven't left out a major step. Other builders will have a different but roughly similar process, and may use different products. It may be a bit more than you asked for, but I wanted to stress the importance of proper prep of the body when still in bare plastic, as this will pay off when doing the final polishing.