So ... you’ve read (hopefully) my articles on:
You (again, hopefully) have a clear picture of what, psychological speaking, painting your RC car body is going to do for you, you have the paints that will meet your needs, you have the right weather/environment for spraying, and you have your carefully prepped body right in front of you.
So I should have some pearls of wisdom to impart to you about spray painting. Well, no, not really ...
As most of the “skill” in spraying is only learned from experience & practice, I did think at first that I didn’t really have anything to say that could really be expressed in words, but I do have a few points – just nothing particularly revelatory.
My view is that preparation is the key to a good finish, but can be difficult and is _always_ tedious, whereas spraying is easy, but can be nerve-wracking.
Pay attention to the weather & don’t push your luck. If it looks like it’s going to start raining soon, don’t try to squeeze a coat of paint in – I have & it always take more time to correct the faults that it would to wait - parts either get rained on or end up with bloom :(
Do follow the instructions about shaking time, even though it’s dead boring.
In colder weather, warm cans up slightly. I find sticking them in your back pocket for a while is adequate, but you do hear tales of cans being warmed up under the hot tap or in bowls of hot water, which I really can’t recommend – I suppose if a can did let go due to overpressure, it would just rupture a little along the seams rather than fragment completely – but even if it didn’t cause any injury, explaining why the kitchen is now a fetching shade of metallic blue (or whatever) would be problematic...
Support the piece you’re spraying – and change the orientation between coats. I generally use a bit of wire through one of the many holes on the body, then change to another hole for the next coat, and so on, to change the orientation of the body, that way there shouldn’t be any “shadows” where the spray didn’t get to. For the final coat, I prefer to support it in its “correct” position (i.e. how it will be on the car), generally with an old 400ml aerosol can, stuck on at the balance point with servo tape or blutac.
Test the paint. Theoretically that would include making sure it’s compatible with the primer you’ve used, and the clearcoat you plan to use, but it’s pretty rare for me to do that. Sometimes I’ll spray a bit of primed plasticard if I’m not sure about a colour choice (or my choice of primer colour), but most often I “test” paint by spraying a puff into clear air ... doing it on cardboard would be more useful, especially if you’re new to this.
Don’t just lean on the spray nozzle; use as little pressure as possible to get a spatter free spray pattern. Move the can in horizontal sweeps, start moving the can & start the spray before you get to the body, and only take your finger off the nozzle after you’ve gone past it.
Keep your distance – most cans have a recommended distance somewhere between 6 and 12 inches (150 to 300mm). With experimentation and/or experience you’ll find distance that works for you - closer increases the risk of putting too much paint on too small an area – which causes runs and sags, and “mottling” (an uneven finish) in metallic paints, spraying at a greater distance can waste paint, give poor coverage, and a dry-looking or orange peel finish.
If something goes wrong – do nothing. Stop spraying & think about it for a week. Seriously – any first aid you do will make it worse, whereas most paint related problems become smaller if you leave them to harden off. I have penned a couple of articles on paint faults & what to do about them & they will be appearing on TB soon.
Build the paint up in light coats. I know the temptation is to think it’s going on really well & just needs a tiny bit more to do it in one coat ... but at best that leads to very long drying times, at worst enormous sags & runs. Your final coat of colour can be a bit heavier: - it might be the second coat, it might be the fourth, but don’t aim to get it fully wet and flat looking if you’re planning to clearcoat – just fairly even. Pics 01 to 04 show a Bruiser body with one to four coats on respectively.
Don’t change cans during a coat – especially with metallic paints. Adjacent cans on the shelf may not come from the same batch, and as most hobby paint is not batch coded, you’ll never know – until you the paint is on the body & is a slightly different shade. This may mean buying more paint that you think you’ll need – some cars you can do in one 250ml can, others need two, depending on the car size & the colour. For instance, a Grasshopper will take one, a Monster Beetle will take two, and the re-re Bruiser in this example could have been done with two, but actually took three - one full can & two halves. It’s a little wasteful, but you have to decide how much your time is worth. Considering the cost of the kit, and the time/expense to strip it & repaint if I wasn’t happy with it, I thought an extra fiver was well worth it.
Small parts take a disproportionate amount of paint. I could give you the mathematical proof, but that would be very dull.
Invert the can after spraying & spray until the output is free of pigment. With modern paints this should be enough to keep the nozzle clear.
Put the body somewhere safe – safe from the weather, dust, insects, kids, pets, etc ideally ... I hang mine in the shed, as that’s where I’ve got.
Leave adequate drying time between coats. “Adequate” is a “how long is a piece of string” question, and will vary on temperature, humidity, the type of paint, and how thick you put it on. Theoretically it’s quite possible to get 4 coats of paint on in one day – but only if the weather is on your side.
Leave adequate curing time before handling – even “dry” paint will fingerprint, scratch and bruise easily for some time. This is another “piece of string” question – but here’s something to consider: fully hardened shells sound different. Really – rap a knuckle on a shell that’s been painted a few days ago, and in comparison to one that was done months ago and it’ll give a sound that’s slightly softer – a long cured shell sounds more “taught” somehow, though it is a subtle difference.
I’m not saying you should leave a shell for six months before you handle it, but do try & resist its charms for a week. If you find a way to do this, please let me know ;) At least be careful about where you handle it – don’t carry it with a firm grip with your thumb in the middle of the roof, for example.
Applying clearcoat (also known as lacquer) in theory will improve the final finish of your RC car body, evening out any tiny imperfections in level, and making any bits left looking a bit “dry” from spraying look wetter. I say in theory, because I’ve found it’s much less important than proper preparation much earlier in the process.
That said, I pretty much always clearcoat a body, as it does add some extra shine – just don’t expect it to make a rough paintjob look better.
Most of the points under “spraying” (above) apply; the only real difference is you need to aim for a thoroughly wetted, flat final coat: that is, stop just before it runs. That’s the tricky bit – knowing just how much you can put on before it does run. If you get one or two small runs, don’t worry – they do tend to shrink back as the solvent evaporates.
As I covered most of the ground already, I’ll round off this article by thinking about a couple of questions.
The first question is whether to do it at all. It’s another process to do, and something else to go wrong –the weather can change, it could get dust on it, the clearcoat could react with the paint, and so on. I don’t want to scare you off, but maybe this is something you need to work up to once you’re confident with the earlier steps?
If you’re in a hurry to use the car, remember that you’ll need to leave adequate curing time for the clearcoat too – this could add another week to the process.
The second question is when to do it – principally before or after applying decals, but also before or after painting any details?
I don’t think I have a real answer to the first part – I’ve done it both ways. If you’re using repro decals (the decent ones that used to be available, not the tat that passes for them on eBay now), then lacquering over the decals – especially if they were a bit matt looking – makes them look sharper, shinier, and therefore better integrated into the finish as a whole. If you’re using genuine Tamiya decals, then they tend to be pretty sharp & shiny anyway, so it’s less of a benefit. I also have to wonder how long lacquer over decals will last before turning a bit yellow & flaking off...
Body details I’m quite clear on though – clearcoating should definitely be done before painting those. Some body details will of course be gloss – door handles, rain channels and so on, but some, like window rubbers would ideally be matt or satin, and their realism would be spoiled by making them super shiny.
What I tend to do is spray the colour coats, then the clearcoat, then paint the body details, and finally apply the decals. I’m not saying that’s the “best” method, but it does work for me.
Take a look at pics 05 & 06 for examples of clearcoating. The first is after the first coat of lacquer: note that it’s fairly shiny, but is hazy and shows a lot of orange peel effect around the point light source. The second is after a heavy coat: the shine is deeper, and the fuzziness caused by orange peel is greatly reduced. It’s possible to go even further than this, but that would involve “rubbing out” – and I’m still too chicken to do that on anything smaller than 1:1 scale vehicles :)
Written by TB member Jonny Retro