Article - Pro Paining Tips Written by: Stevo309

This article covers the preparation and painting of ABS shells.

Smoothly does it

I'll start by saying straight away that the quality of the finish you achieve depends on the quality of the preparation, the more time you take to get the foundation right and the more time you take to complete each step carefully and slowly the better your end result will be.

As I rule I always say that if you can feel it, you will see it. What I mean by this is that if you run your fingers along the surface to be painted and can feel any imperfections then it *will* show through the paint generally. Take your time to remove all paint that you can and smooth any imperfections out of the plastic using a fine grade wet and dry paper. I normally use 1500 grit for this in warm water containing washing up detergent. This should give a smooth and flat finish but look very closely and you'll see millions of tiny scratches, perfect for the paint/primer to grip onto. Be careful not to sand too aggressively though on your bare plastic as you could lose some of the critical body detailing. The main thing is to remove old paint and the smaller scratches.

If your shell needs repairing this is the time to do it before any primer goes on, deeper scratches can be filled using automotive body filler and smoothed, again smooth this down until you can't feel any imperfections.

If you're painting a new shell then the above still applies, I always wet sand new shells in the same warm soapy water to create those vital minute scratches giving the primer a surface it can "key" to. Once you've finished rinse the shell in clean water and leave to dry. Be careful at this time if you use a cloth or paper to dry the shell as you may be leaving particles of dust of paper etc behind, best to let the shell dry of it's own accord if you can. The shell should look like it has a matt finish, perfect!

It's prime time!!

As Tamiya don't sell an acrylic primer in the UK I actually use an automotive plastic primer or Tamiya Acrylic matt white. Add the primer in thin even coats. Here are my top tips for using spray can paints:

  • Warm the can in hot water for about 1 minute before use. (This helps the paint to mix and increases the internal pressure inside the can which gives a more consistent and finer spray)
  • Spray in a ventilated but warm space. A garage is perfect. Summer months are best of course but you can warm the air first using an electric heater to increase the temperature and lower the moisture in the air.
  • Hang the shell or mount it on a post high up give you good access from all angles and away from the potential dust that may be kicked up from a work surface.
  • Spray even thin coats of the spray from a distance of about 8 inches. Sweeping the can past the shell and pressing the nozzle down only as you pass is the best technique.
  • Don't be tempted to put too much on, you just need coverage, runs are a nightmare to deal with but you can always add more coats of paint.

The above techniques obviously apply to the primer stage. Once the primer is dry check for any scratches still showing through and if necessary wet sand again and apply more primer. Do this until you are happy that you have a blemish free and smooth foundation for the top coat of paint. If you want you can wet sand the primer just to get a smoother finish before applying the paint. Wet sanding rather than dry sanding is always best as the water helps remove the paint from the paper which stops it clogging and makes it more effective. As a safety issue it also eliminates dust that is best not to breathe in.

Time for top coat

I have used various types of paints on my shells in the past but have found Tamiya Acrylic paints to be the best bar none. Automotive spray can paints can give good results but due to them having a larger nozzle hole they generally tend to give a rougher finish, of course it's still possible to flatten this down and achieve a great result but it's harder work. I do actually use automotive paints on my runners where a thick durable finish is the main priority rather than a super deep and flat finish but more on the finishing later…

Next up is your top coat paints. If you plan to use more than 1 colour as a rule it's best to spray the lighter colours first as the darker colours will show through lighter ones and take many more coats to cover. Spray your paints in light even coats and leave to dry for at least 2 hours between coats. If you can a longer rest is advised and if necessary you can wet sand each coat as above to get a smooth finish. I only really think this is necessary on the final top coat before lacquer but it's up to you. Once all top coat colours are on leave the shell to cure for at least 24 hours before you do anything. It's an agonising wait but trust me it's worth it! As I have just mentioned it's a good idea to wet sand the final layer down, this gives a lovely flat surface for your lacquer.

Lacquer

Not everyone uses lacquer but there are really many benefits to it as follows:

  • It seals in the paint to give a protective shell
  • It will give the paint a better shine and visually more depth
  • It can help prevent UV paint pigment degradation.
  • It can be flattened and polished to a mirror finish without wearing down top coats of paint.

The main point for me is the last one, as a rule I will apply 3 coats of lacquer and then leave overnight before polishing to a mirror using automotive polish and elbow grease. You really can repeat the polishing time and time again until you get a truly glass finish. Remember though, you are removing the lacquer as you do this so keep an eye on your polishing cloth for colour, if you see any then you've gone through the lacquer, don't worry though you can always wet sand and apply more if you need to. You can accelerate this process by wet sanding the lacquer using very fine grade paper (1500 grit or finer) before polishing but be careful, it won't take much to remove the lacquer!

Decals

Some modellers prefer to apply decals before the lacquer process above but I personally don't. It's a subjective thing but here are my reasons for not doing it:

  • Fear of a reaction between the lacquer and the decals
  • Fear of an edge of decal not being down 100%
  • No chance to remove the decals and move then etc.
  • Easy to polish through the lacquer at the edges of decals where it's raised
  • 1:1 vehicles would have sponsor decals applied over the top of paint as vinyls generally.

Up to you of course but whatever you do I hope this article has helped to give some pointers for perfecting your technique.

 
 
 
 
 
 
 
 
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