How to prepare body for painting

[Greenghost]

Hello,

 

I'm new to car building.  Never done before.  I have some 1/43 BBR (resin body) and some Tameo (metal body) cars along with the regular 1/24 and 1/20 plastic kits.  

 

My question is how should I prepare the bodies for high gloss finishing?  What type of primer and paint do you recommend to use?

 

Thank you

[Trash]

Personally I like Tamiya Fine White primer. As with aircraft, put together what you can, eliminate seams and always wash the kit before priming.

As for a gloss coat I like to paint the base colour and then do a light sanding until it is clean of blemishes and then gloss coat, and then again sand and use a rubbing compound to get it to its final appearance.

Gloss takes practice and a nice clean spray area, no dust.

 

 

[Slartibartfast]

A long-ago article in a mag showed a build article for a TV Batmobile. Several coats of flat black primer were polished to a HIGH shine.  Of course, if you want a color other than black, gray or white...

Edited October 18, 2017 by Slartibartfast

[Greenghost]

Thank you guys...will give it a try. 

[MoFo]

In terms of plastic... there's not much difference for painting a car or a plane.  Tamiya's spray primers are excellent, but Alclad's Microfiller primers will work just as well.

 

More importantly for cars is the using a colour of primer that will a.) give you a neutral base for your paint coat and b.) block the plastic underneath.  A white primer coat is best for most colours, unless you're you're after a specific effect (say, silver for a candy finish).  Reds do well over a pink primer (this is how Ferrari paints their cars; Tamiya recently released a pink primer/surfacer for this reason), while black doesn't really matter.  If the plastic is a particularly strong colour that will be hard to cover, it can be a good idea to use a grey primer first, to kill the colour, before spraying your white primer.  Basically, if the colour of the plastic will impact the paint, use primers first so that it doesn't.

 

Additionally, you need to be careful of how the plastic was coloured.  Some manufacturers use pigments that can leech out through the paint, tinting the colour over time.  You can test for this by soaking a length of sprue in thinner for a few days (Tamiya's lacquer thinner is recommended, but 99% isopropyl should also work).  If the thinner stays clear, you're fine; if it gets tinted, the colour will bleed. There are a couple of ways to deal with this: one is to soak the parts in thinner until the colour stops leeching out; another is to use a primer sealer to act as a barrier (Zero and MCW both make them); while some people feel that a primer coat of Tamiya AS-12 will act as a barrier (though I've heard mixed results with that).  Tamiya, Hasegawa and Ebbro have all suffered from this, with red plastic being particularly notorious.

 

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For BBR and Tameo...

 

Regular model paints don't stick well to white metal - it chips off fairly easily.  You'll want to give all parts a good sanding with ~400 grit sandpaper to roughen up the surface slightly and provide a key.  Some people think soaking parts in vinegar for a while helps (probably doesn't hurt).  Most importantly though is to use a *metal* primer.  Gunze make one, Tamiya makes one, most hardware stores will have automotive metal primers.  The metal primer will allow your paint to stick to the metal, which will dramatically reduce/eliminate chipping and flaking.  You can then use your normal primer to get an even base for your paint.

 

You can use a resin primer for resin bodies - again, Gunze have a specialty resin primer - though I never have.  A decent lacquer-based primer sticks well enough in my experience.  Particularly with BBR's resin, which tends to have a fairly matte finish.

 

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For colour coats, that's mostly a personal preference.  Tamiya's spray cans (decanted or not) are excellent in my experience.   If you're looking for the easiest way to get a good gloss, that's probably it. 

 

Since it sounds like you're looking at race cars (Tameo, BBR, 1/20), there are a few manufacturers who sell automotive acrylic lacquers (DuPont, PPG, etc.) in accurate, colour-matched race car paints.  Zero is probably the biggest name available from Hiroboy in the UK, Spot Model in Europe, Hobbyworld in the US and Paintsmodelsandmore.com in Canada.  Model Car Wold (MCW) also have a wide selection, though it's geared more to US racing.  Gravity Colors are a newer brand but gaining popularity with a pretty good selection.  All three brands are basecoat/topcoat though, which means the colour coats (base coat) are matte, and you need to apply a separate gloss topcoat.  Which isn't a big deal, because...

 

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You should apply a clear gloss over your paint anyway.  That helps avoid polishing through your colour coat - if you see colour on your polishing cloth, it means you've burned through the gloss coat, so you need to stop.

 

As for *what* gloss to use, again that's mostly personal preference.  Tamiya's spray gloss is very good, but because it's a lacquer it can be very hard on decals.  This can be a problem for race cars.  You *can* spray it over decals, but you need to build up light, misty coats, and leave the model until it's *fully* cured (this goes for any lacquer gloss).  As a gloss over a matte basecoat though, it's fine.

 

Because of the issues with lacquer clears, a lot of auto modellers use Urethane 2K clear coats.  These provide a deep gloss and cure to a harder finish than lacquers, which helps with polishing, but they are also highly noxious and *must* be used with proper safety precautions.  Zero and Gravity both sell 2K clears, but you can also source them from most auto body supply shops.

 

 

[Greenghost]

MoFo,

 

Thank you very much for such extensive and comprehensive explanation. 

 

It it answers perfectly my questions.  

 

As for resin lacquer based primers, can I get them in any hardware or automotive store?

 

 Thank you 

[MoFo]

 Gunze is the only company I'm aware of that makes a primer specifically for resin - Mr Resin Primer.  I've never had a problem with Tamiya's spray primers, Mr. Surfacer or Alclad's Microfiller primer when sprayed on resin, though.  And I've painted a bunch of 1/43 resin cars.  

 

That said, if you want to go the hardware store/automotive paint route, these types of paint are called "high build primer".  Automotive suppliers will have it (pretty sure Alclad's primers are re-bottled DuPont paint), but you'll probably need to buy a lot, so it won't be cheap.  Duplicolor, Krylon and the like will have spray cans too.  Although, unless it's a model paint you know is safe for use on plastic, I'd test them first before spraying on styrene (resin and metal should be fine, though).