The standard of the final finish you’ll get is proportional to the time you put in. In theory, painting an ABS (aka styrene) Tamiya body can be very quick – cut off any sprues from the window apertures, and give it a quick blow over. That’s barely enough if you’ve just bought a Lunchbox as a first car for your kids to use in the street – in which case you _know_ it’s going to get trashed very quickly – but I tend to go a lot further...
Remember, the standard of the final finish you’ll get is proportional to the time you put in – a super shiny paintjob is never quick.
Any sprues still on the shell – a recurring Tamiya favourite seems to be the sunroof aperture - need to come off before you start. Twisting them off or cutting very close to the body always seems to end up in a tear and missing material, and risks creating a weak spot where cracks/breaks can start in use, so I always trim the sprue off a little short with a decent pair of cutters, and then trim back with a craft knife before sanding off the remains.
See the pics labelled 1 to 4 for examples
“Flash” (Insert your own “aah-aah” sound effect here ;) ) is protruding, unwanted extra plastic found where the parts of the mould have not precisely matched up during the injection process. Tamiya injection moulding is generally very good regarding this sort of fault (compared to, say, older Airfix kits) – but it’s still something you need to look out, if you’re in pursuit of that perfect finish.
The worst examples I’ve seen are on the Sand Scorcher and Sand Rover drivers, but even on the example re-re Bruiser shell here, there are a couple of areas that need attention – on the upper edge of the cab back, and on the tops of the front wings - see pics 5 to 8. Flash is best removed with gentle sanding – pic 5 shows where I went too far & lost some detail :(
Washing in warm water with plenty of washing up detergent, then rinsing thoroughly not only removes any mould release agent, but also any fingerprint residues, fibres from the box, and seems to ground that lingering static charge. I also give the body a light scrub with a new, but very cheap toothbrush.
Be careful when you dry the body – if you live in a hard water area & need to quickly dry things by hand to avoid water spotting, shaking & blowing the recesses is best, but if you do have to use a of cloth, make sure it’s clean & won’t undo what you were trying to achieve by leaving lint (fibres) behind. On a similar note, make sure you scrub your sink before letting your RC body anywhere near it.
Perhaps this seems a bit trivial & very obvious, but even if you go straight to painting without any intervening rubbing down or priming, this is a step you just shouldn’t omit.
For anything but the most basic paintjob, I’d thoroughly recommend “keying” – that is, a light rub down with 600 or 800 grit (or finer) Wet & Dry paper. This should be done wet, with a little washing up detergent, not only to improve the lifespan of the paper by avoiding clogging, but also to avoid heat building up, potentially causing surface melt.
Doing it wet will also show you when you’ve done enough: compare the “before” and after shots & you’ll see that before keying (pic 9) water sits & beads on the surface on the plastic with a very visible meniscus, while in the “after” shot (pic 10) the water still clings, but in much thinner & wider sheets.
This has long been a part of my RC body method, and recently it’s become pretty much essential on Tamiya cars - the re-release Scorcher has a couple of nasty dimples on the roof that need attention, the re-hashed Sand Rover has huge, amateurish gouges for the DT-02 chassis shock towers, and the Bruiser (used as the example body for this piece) has a couple of extra holes in the sills that really deserve to be fixed better than applying the decals supplied with the kit (see pic 11). Obviously this is not part of the “quick” way of doing things.
First, sand the inside edges of the holes to help the filler stick.
Putting something at the back of the hole – preferably thin ABS sheet, glued on (after keying both the patch and the body) with regular poly glue will help no end, as it will let you compress the filler into the hole without it extruding itself from the other end; see pic 12 for an example.
Once the glue is properly dry (you really need to leave in several hours, preferably overnight) you can apply your filler of choice (see pic 13).
I’d recommend Squadron white putty or Revell “Plasto”, but in both cases be careful not to overwork the filler, as it does partially melt the ABS. You also need to fill the hole slightly proud of the surface, as these fillers will shrink as they dry.
I’ve also had success with Milliput silver/grey epoxy putty, but it is a lot of fuss for small holes – mixing equal parts of the two sausages, having to wash your hands because they’ll have got thoroughly sticky by then, getting the right amount in the hole, then getting it wet to smooth things out, and of course the setting time is longer than 1-part fillers.
Once your filler is dry (again I’d suggest you need to leave it overnight) you can tackle sanding back to get the levels right. I would suggest you use a fairly gentle grade of paper (800 grit or so) as although it will take longer, there’s much less chance of going too far. At this point you may see that your filling has been a little inadequate, in which case, repeat the filling & sanding again. You may need to do this several times to remove any imperfections – just how many times is really down to your patience. When it looks good, or if you reach the point where you find that each cycle is introducing as many new problems as solving old ones, then it’s time to move on.
You may want to use a small sanding block (instead of just your fingers) on flat surfaces, as sanding freehand tends to mean your finger tips will push the paper down into any slight depressions, making them worse, or sand more where the material is softer – i.e. you’ll take off the filler before the plastic of the body – meaning you’ll never fill that hole.
Depending on what paint system you’re using, you’ll probably have a choice of what sort of primer to use. My favoured brand/system (Hycote acrylic) comes in a lot of different flavours, white, grey, red, white “plastic”, grey “plastic”, red “plastic”, white “high build”, grey “high build”, and yellow “filler primer”... in general, I’d suggest a “plastic” primer as it seems to stick better and is a bit more flexible, and choose a primer colour based on the colour the shell is moulded in, and the colour you want to paint it.
I wouldn’t use white primer unless the body was white to start with, or the colour I’d be spraying over it was very light (yellow, orange, very light blues & greens).
Grey primer is generally the way to go for darker moulded or previously painted bodyshells & colour coats (blues, blacks, etc), with red primer an outside chance for red paint.
The problem really comes if you want to paint a light colour over a dark shell moulding – e.g. white paint on a black shell – you have to balance the conflicting needs to cover the moulded colour with the need for the colour coat to adequately cover the primer ... on balance, probably the grey as it’s half way between.
In my experience, “pearlescent” paints are like metallic paints, only much less dense. It can be difficult to build up an even colour, so I’d also recommend an “undercoat” of an inoffensive silver colour.
... I’ll cover Guide coats, priming, rubbing down & undercoating :)
Written by TB member Jonny Retro