Very few subjects in scale modeling are as confusing as paint types.
Internet is packed with information on the topic. While most of it is somewhat correct, there are also a lot of misconceptions and anecdotes that obscure the big picture. As with anything, we can also encounter a ton of marketing BS, which complicates the matter further. Many inexperienced builders will often, in good heart, jump to answer questions despite having limited knowledge on the subject. Those who asked them will then go on to tell others. And so the misconceptions spread.
On the other hand, we can also find quite a few dry, Wikipedia-like articles. While those contain a lot of good information, it’s often buried under a ton of excessive technical data. It does little to clarify the subject. . None of us need to know the history of automotive paints to airbrush our models. Or all the chemical compounds that can be used to make pigments. Details like these are of little use, even to the most advanced modelers.
Let’s try to keep it simple.
Before we talk about the paint types though, let’s take a quick look at what goes into making them.
Pigments are responsible for color, opacity and texture. Quality modeling paints use finely ground pigments, which are necessary for smooth finish that doesn’t obscure the details. More opaque pigments allow for better coverage when painting in thin coats. In addition to being finer, pigments in modeling paints also withstand UV light better than most conventional paints. Varnishes (clear paints) on the other hand, often contain no pigments at all. Despite some builders repeating things like “Acrylic paints use acrylic pigments.”, pigments themselves actually have nothing to do with paint type.
Binder is the most important ingredient. You could think of it as a ‘foundation’ of the paint, influencing most of its characteristics. It binds the pigments together, determines the adhesion and curing method. Binders also strongly influence the flexibility, durability and finish (matte / gloss). Paints designed for plastic models usually use either acrylic resin or oil-based binder. This is why some sources only state acrylics and oils as modeling paint types.
Solvent / Liquid is a substance used to dissolve the binder, reducing paint consistency. If you leave paint uncapped long enough, solvent will evaporate, turning it into thick, gunky mass. Many model builders, including me, categorize acrylic paints based on solvent they use. Common acrylic solvents include water, alcohol (not the drinking kind) and cellulose. Oil paints, on the other hand, tend to use things like turpentine or mineral spirits (white spirits).
Additives are various substances manufacturers add to their paints and thinners to alter their characteristics. Properties like surface tension, drying time, texture etc. can be altered by various additives.
By carefully manipulating each of the ingredients, manufacturers can fine-tune paint’s behavior. The exact formula is often a trade secret.
Much of the confusion around the paint types stems from the naming conventions. Some people will only name two kinds of modeling paints. Others will say there are three, five or even more. Some manufacturers call their lacquers ‘acrylics’. Best part is – technically most of those are correct.
Personally, I like to categorize modeling paints into five types. Three of them being acrylic and the other two being oils.
Water-Based Acrylics (Aqueous Acrylics)
Aqueous acrylics are non-toxic and have basically no smell. It makes them the safest out of all paint types.
|Initially marketed with emphasis on safety and ease of use, they got a bad rep as paints for children. At the time “serious” modelers only used enamels. Water-based acrylic paints came a long way since then. Nowadays they’re the most used paints in scale modeling. Manufacturers produce them in hundreds of colors and variations.
Aqueous acrylics use water for thinning, though many companies produce their own thinners as well. Sometimes manufacturers offer different thinners for different applications – either hand painting or airbrushing. If you’re not on a tight budget, consider using them. Brand-name thinners will often improve paint’s characteristics and make it easier to apply.
Overall, whether hand painted or airbrushed, they perform quite well and create a good baseline. That said, other types of paints outperform them in both of these areas.
Acrylic paints dry quite fast. While helpful (no need to wait for hours between coats), it can also be a curse. Tip dry is very common when airbrushing, which necessitates the use of retarders / flow improvers or needle lubrication. It also limits their usefulness in applications requiring blending and smooth gradients, like some weathering effects.
They also fall behind other paint types in durability. While not horrible, they simply cannot match enamels and lacquers.
I recommend water-based acrylics for anyone who’d like to get into painting. Their safety, ease of use and wide color range make them an excellent choice for beginners. Don’t think of them as entry level paints though. Many advanced modelers don’t want to deal with harmful effects of other paints. Those guys stick with acrylics and still get great results.
Notable brands include: AMMO by Mig Jimenez, Citadel, AK Interactive, Mr.Hobby N-series (Acrysion), Vallejo.
Sometimes called solvent-based acrylics or acrylic-lacquers.
Notable brands include: Tamiya Acrylics, Mr.Hobby H-series (Hobby Color).
Lacquers (Cellulose-Based Acrylics)
Welcome to the heavy weight.
|The name “lacquers” can be somewhat confusing. It’s often used to describe any kind of protective gloss coating, particularly used on furniture. In scale modeling, we use this term for acrylic paints using a cellulose-based solvent.
With lacquers, safety goes out the window. They have extremely potent smell and toxic fumes. Use any reasonable precautions, including good ventilation, spray booth, respirator and nitrate gloves.
Due to cellulose-based solvent and “hot” thinners they can also eat through plastic, other paints and decals (in addition to your lungs) when applied carelessly. More than any other type, they should be sprayed in thin coats.
Due to very quick dry time, lacquers are extremely hard to brush paint. Unless you’re Lincoln Wright of course, then you make it look easy. In turn, they offer hands down the best airbrushing performance out of all the paint types. Despite drying extremely fast, lacquers do not suffer from tip dry.
They also produce the most durable finish out of all scale modeling paints. In addition, their ability to “eat” into plastic and underlying coats of paint further improves the bond. It also makes them excellent primers.
In addition, lacquers have the best looking metallic paints.
Notable brands include: Mr.Hobby C-series (Mr.Color), Alclad II, Mr.Paint, Tamiya Lacquers (also their spray paints), Zero Paints.
Enamels were the very first paints designed specifically for use on plastic model kits.
|They usually have an alkyd binder (though some companies started using acrylic resin in recent years) and petroleum-based solvents, which classified them as oil paints.
Because of it they have a strong smell and harmful vapors, as do their thinners. At the very least ensure good ventilation when using them. When airbrushing use respirator and spray booth.
Enamels are some of the longest-drying paints, as they need to undergo curing process – chemical transformation which turns them into a hard, durable shell. This process continues long after the paint is dry to the touch and can take up to a week.
Long dry time makes them excellent for brush painting, since they have enough time to self-level and hide brush strokes. Any mistakes can be cleaned easily, as we can reactivate the paint long after it’s touch dry. They’re also great for weathering, with companies like AMMO and AK producing a wide range of enamel-based weathering products.
This paint type can be thinned with petroleum-based products, like mineral spirits (white spirits) or xylene. Turpentine can also be used, though brand-name thinners usually perform the best. Odorless oil thinners for artists are also a good alternative. Keep in mind most enamel thinners can make plastic brittle if allowed to pool on the surface.
Notable brands include: Humbrol, Revell, Model Master, Testors, Tamiya Enamels. Also, weathering products by AK Interactive and AMMO.
|Oils are the oldest out of all the paint types I listed here – their usage can be traced all the way back to Middle Ages. Back in the day artists had to produce them on their own. Nowadays they’re readily available at your local art store.
Linseed oil (also known as flax oil), usual binder, gives these paints very glossy finish and extremely long drying time. Obviously we don’t want to wait weeks or months for paints on our models to dry. To speed up the process we need to drain excess oil by leaving paints on a piece of cardboard for a day or two. Some companies, like Abteilung 502 and AMMO, produce oil paints with less linseed oil, designed specifically for model builders.
In scale modeling, we use oil paints almost exclusively for weathering. They work extremely well for most weathering techniques, including washes, filters, streaking, rust, dirt, mud and so on. Figure painters also enjoy working with oils, since, like enamels, they can be easily blended into smooth gradients.
Oil paints have basically no smell and are completely safe to use. They mostly use same thinners as enamels though (turpentine and white spirits), and those can be harmful. For safety and comfort, I recommend using high quality odorless thinners.
While somewhat pricey, quality oils are definitely worth the money. Keep in mind we need to thin them extensively for weathering, so a single tube of color might last for years.
Notable brands include: 502 Abteilung, AMMO (Oilbrushers), Winsor & Newton, Talens, Daler Rowney.
Other Notes & Tips
There are also some other topics related to paint types I’d like to touch on:
Layering Different Paint Types
Using different paint types over each other can be tricky. While using exclusively water- and alcohol-based acrylics doesn’t pose much problem, lacquers and enamels are another story. General rule of thumb is starting with the “hottest” paints and moving to safer ones as we build up layers.
Technically we can use lacquers over enamels, other acrylics and decals, but it is quite risky, as lacquer thinner can dissolve them. To limit the risk, we can apply lacquer in very thin, misty coats. This way paint reaches the surface nearly dry, limiting its window to affect earlier coats. Make sure earlier layers had enough time to cure as well. I suggest practicing on spoons or spare parts before doing it on a kit.
Whenever we move up in paint “hotness”, we should also lay down a protective clear coat (varnish) beforehand. It’ll help limit the effect paint has on earlier layers. Varnishing also helps prepare the surface for different stages of the build – from painting to decals, from decals to weathering.
Workflows differ from builder to builder, but basic, rather safe one, would go like this:
- Primer (Lacquer);
- Lacquers or alcohol-based acrylics with lacquer thinner;
- Clear coat;
- Clear coat;
- Weathering (enamels and/or oils);
- Final clear coat (topcoat).
Of course, not all the steps need to be present.
Drying vs. Curing
Sometimes used alternately, terms drying and curing refer to different chemical processes. Pretty much all paints dry, but not all of them cure.
Drying means solvent & thinner evaporation. Depending on the solvent, they might take a while to fully evaporate.
Curing usually means binder polymerization (although there are other curing methods). During this process paint undergoes chemical transformation, forming a durable shell over the painted surface.
There is actually another way of categorizing paint types – based on the drying mechanism. In this approach, paints are split only between lacquers and enamels. Paints which only dry are considered lacquers, and paints which dry and then cure are considered enamels. This system is not widely used in scale modeling though – neither by model builders nor paint manufacturers. Interesting fact, but not something you really need to remember.
Thinners vs. Cleaners
Another example of terms (and products) often used interchangeably. Not entirely wrong either. We can use thinners to clean our tools. We can also use cleaning agents to thin the paints somewhat. That said, we should use appropriate product for the job.
As I mentioned earlier, most brand-name thinners include a fine-tuned mix of various chemicals, designed to maximize the paint’s performance. Because of it, I suggest using them over the budget options if you can afford it. Sure, many cheaper alternatives, like IPA (isopropyl alcohol) for acrylics, might do an adequate job. Although they might also be the difference between getting acceptable results and getting great results. Some builders recommend Windex and other products with ammonia to thin the acrylics. Don’t bother. They break up the paint, not thin it. Ammonia is a good cleaning agent, not a paint thinner.
Cleaners on the other hand are meant to strip the leftover paint from our tools. I highly recommend using budget options here instead. Cheap lacquer thinner will clean your airbrush just as good as brand name tool cleaner – at a fraction of the price. It’ll easily clean lacquers, acrylics and even some enamels.
Example budget cleaners for each paint type:
- Water- and alcohol-based acrylics: IPA, denatured alcohol, Windex, hardware store lacquer thinner;
- Enamels and Oils: White spirits, turpentine, lighter fluid (never use it to clean an airbrush though);
- Lacquers: Hardware store lacquer thinner.
Just to be safe though, test them in a paint tray before using any of those in an airbrush or on expensive brushes.
Hopefully this article helped you understand different paint types used in scale modeling and cleared the common misconceptions.
Huge thanks to Guillaume from AMMO by Mig Jimenez for proofreading this article for me.