I'm going to start with a disclaimer. I'm not a paint chemist/technologist - merely a modeller who has used Tamiya paints for many years. These are simply my thoughs and observations.
Tamiya's range of acrylic paints has been with us since the early 1980's. That's well over 25 years, but still, some modellers regard them with fear, uncertainty and doubt and refuse to use them, often simply because they're "different" to the enamels they're familiar with. Having said that, it's fair enough if one has a significant investment in other paints, is happy with their results and really has no need to change to another system.
However, for someone starting out in modelling or someone returning to modelling after a long period away, there's really nothing rmysterious or intimidating anout them, like any tool, you just have to learn how to use them correctly.
Is it a "true" acrylic?
A common misconception which I've seen on various model forums is that Tamiya's acrylics are not "true" acrylics because they can be reduced (thinned) with solvents other than water. I believe that this has come about because model paint manufacturers have put a great deal of emphasis on the easy clean up of acrylic paints using water.
The reality is that while most uncured acrylic paints are soluble in water, this is irrelevant in determining whether a paint is acrylic or not. The term "acrylic" describes a particular class of polymers (essentially a type of plastic) of a particular molecular structure, formed by the polymerisation (or joining) of smaller molecules (or monomers). Acrylic paints contain binders made up of chemicals based on these monomers. What this means is that acrylic paints don't simply dry. As the paint dries, there is a "natural" molecular attraction which causes these monomers to join together to form "long chain molecules" (aka polymers). Essentially, the paint becomes a film of "plastic". After the curing process is completed, the paint is unaffected by water.
(Apologies for the chemistry lesson - Industrial chemists and paint technologists are welcome to add comments/corrections.)
Over the years, I've seen many different suggestions for thinner for Tamiya acrylics, ranging from water to lacquer thinner. Whatever one uses, it does not change the fact that Tamiya's acrylic paints are (chemically) based on acrylic compounds, so they are undisputably acrylic paints.
What's the best thinner for Tamiya acrylics?
One of the most frequently asked questions on modelling forums is "What's the best thinner for Tamiya acrylics?"
Looking around.various forums, you will see almost everything from water, Windex, automotive windshield washer solution, Isopropyl and denatured (ethyl) alcohols, even laxquer thinner.
Despite what you may read, the best thinner for Tamiya's acrylics is Tamiya's own X-20A acrylic thinner. My understanding is that this is a mixture of Isopropyl alcohol, propylene glycol and other alcohols. It's the one which works the most reliably and consistently.
Let's look at some of the alternatives mentioned:
[ol]Water: While water will work to a certain extent, it has a tendency to degrade both the covering ability and adhesion of the paint. Push it too far and the paint will tend to bead and not stick. Also, tap water can vary considerably from one locality to another, containing dissolved minerals abd chemicals which may affect the behaviour of your paint. If you must use water, use distilled water for cosistency.
Windex: Windex is the trade name of a window cleaning product manufactured by S.C. Johnson & Co. and is available in many (but not all) countries. Windex is primarily water with a quantity of isopropyl alcohol and ammonia. While some people report successfully using Windex as a thinner, I wouldn't recommend it. The ammonia content will actually break down dry/cured acrylic paints and, I suspect, inhibits or retards the polymerization process when added to fresh paint. On the other hand, it can be useful in removing paint from your airbrush, but it must be rinsed very well with clean water afterwards as ammonia can be corrosive.
Windscreen washer solution: Some people use windscreen washer solurion. There are many different proprietary mixes, many containing (mostly) water, isopropyl alcohiol, propylene glycol and some detergents. Coincidentally, Tamiya thinner is composed of Isopropyl alcohol and propylene glycol, but in a higher concentration. I haven't tried windscreen washer solution, so I can't personally comment about its effectiveness. I rather suspect that it's only marginally better than water because the detergents act as a surfactant and reduce the surface tension, helping it to spread rather than bead.
Isopropyl alcohol: This is the primary component of Tamiya's own thinner and many people swear by it. It's often available from supermarkets and pharmacies in the form of "rubbing alcohol" at a 70% concentration. However, the preferred oprion is 90% (or higher) Here in Australia, it's much more difficult to obtain (and much more expensive, often being about the same price or more than "genuine" Tamiya thinner) than it is in, say, the United States. When used as a thinner on its own, Tamiya paint has a tendency to dry very quickly and depending on air pressure settings and distance from the airbrush to the subject, may cause the paint droplets to dry in mid-air between the airbrush and the surface being painted, resulting in a coarse, gritty finish.
Ethyl (denatured) alcohol: Ethyl alcohol is somewhat compatible with Tamiya acrylic paints. Here in Australia, it's much much cheaper than Tamiya thinner or Isopropyl alcohol, and much more obtainable. (1 litre of methylated spirits is a bit over $3.00) As a thinner for Tamiya paint, it's a little more aggressive and dries even faster than paint thinned with Isopropyl alcohol. It is "wetter" than Tamiya thinner and one can thin to a much greater degree and still get coverage where paint thinned to the same extent using Tamiya's thinner will bead and separate. I'm talking about thinning to 80% or higher thinner to paint. For certain applications, I like my paint very thin. and it works for those purposes. I do airbrush at fairly low pressures and at very close distances though.
When using either of the alcohol options above, you may wish to add an amount of acrylic retarder (available from artists supply stores. Many retarders are based on propylene glycol (another of the "main" constituents of Tamiya's paint and thinner) and extend the drying time of the paint. Also note that the alcohol options are not recommended for Tamiya's gloss acrylics, as the fast drying associated with the alcohols means that the paints may "flash dry" before a continuous smooth film forms on the paint, leading to a "dull" surface.
Lacquer thinner: Some people thin Tamiya acrylics with Lacquer thinner. "Lacquer thinners" vary quite considerably from brand to brand and may contain varying concentrations of solvents, many of which are unfrinedly to styrene. Many of the "hobby branded" lacquer thinners (reg. Tamiya, Gunze's "Mr Thinner" etc) are said to work with Tamiya paint What's the story there?
Well, I haven't tried either of these so I haven't any personal experience, but I'll make a semi-educated guess. The "hobby brand" lacquer thinners are formulated to work with paints for styrene models, so by necessity, they're less agggressive than "generic" lacquer thinners. It's said that you can leave styrene parts soaking in Tamiya or Gunze lacquer thinners with no ill effects, whereas if you try that with most generic lacquer thinners, you very quickly have a puddle of goo.
Now most lacquer thinners are a blend of alcohols and other aggressive solvents. My suspicion is that the "hobby brand" lacquer thinners contain a higher concentration of compatible alcohols and lower concentrations of the other solvents, which may explain why they work with Tamiya paints.[/ol]
Another common misconception which is often bandied about is that Tamiya paints are designed for airbrushing and can't be hand brushed, or don't hand brush very well. When they first hit the market in the early 80's Tamiya's acrylics hand brushed remarkably well. Under optimum conditions, you could brush it straight out of the bottle and when dry, they were so dead flat and streak free that it was difficult to tell they were brushed and not sprayed. Unfortunately this changed some time around 1990 and they've been finnicky to hand brush ever since, so it is true that today's Tamiya paints can be difficult to hand brush out of the bottle, but if are prepared to do a little preparation, they do hand brush rather well.
For successful brush painting with Tamiiya acrylics:
Stir the paint well.
[ul]30 seconds of shaking the bottle is pointless. Open the bottle and stir until there are no lumps or strings of paint. [/ul]
Don't paint out of the bottle.
[ul]Decant a small amount of paint onto a suitable palette [/ul]
Thin your paint
[ul] Add a small amount of Tamiya thinner, about 10%, and stir well (EDIT: Recent testing indicates that this should be closer to 30%. Take this as a starting point and adjust as required.) [/ul]
Use good quality brushes
[ul]Forget about the cheap "Dollar store" 10-on a card for $2.00 brushes, I'm talking about red sable/Kolinsky sable or high-grade Golden Taklon. Yes, we are talking a lot of $$$ but the results are worth it and when looked after properly, your brushes will last for many years.[/ul]
Put a small quantity of clean thinner in a suitable container (or another well on your palette)
Moisten your brush slightly in the clean thinner before dipping it into the paint. This "lubricates" the brush and allows the paint to flow more smoothly, both onto and off the brush.
(Dipping into the thinner, you only want it slightly moist, not wet. If you pick up too much thinner, wick it off on a paper towel or tissue.) Repeat this step every other time you "load" the brush with paint.
Brush in short, smooth, even strokes, preferably in the same direction. Only brush "back" as far as the last "wet edge". IMPORTANT: Do not brush over previously painted areas which may appear dry. Doing so will "roll it up" in ugly chunks. If you need to overcoat an area, allow it to dry and cure overnight before recoating.
If paint os starting to dry on the brush, stop for a few minutes and take the time to clean the brush. Not doing so will mean degraded btush performance, resulting in streaks and brush marks and the possibility of dry chunks of paint flaking off the bristles onto the surface you're painting.
Allow to dry overnight before painting any successive layers or colours.
Addendum:
Is it dry? It's still soft
One of the big selling points of Tamiya (and other) acrylics is the "fast drying" sspect. As I mentioned above, acrylic paints don't just dry, they cure. It's important to understand that there's a difference. Tamiya acrylics, particularly their flats, "touch dry" exceptionally quickly, sometimes within seconds of application when airbrushing. However, this simply means that the solvent has evaporated. It can take considerably longer for the paint to fully cure. During this time, the film of paint is quite fragile and is easily scratched. In the case of flats, it can be 18-24 hours before it reaches full hardness. Tamiya's gloss acrylics can take even longer due to the less permeable glossy surface film inhibiting the evaporation of the solvents (which in turn inhibit the curing process). Depending on the thickness of the application, this can sometimes take a week or more.
Tamiya's range of acrylic paints has been with us since the early 1980's. That's well over 25 years, but still, some modellers regard them with fear, uncertainty and doubt and refuse to use them, often simply because they're "different" to the enamels they're familiar with. Having said that, it's fair enough if one has a significant investment in other paints, is happy with their results and really has no need to change to another system.
However, for someone starting out in modelling or someone returning to modelling after a long period away, there's really nothing rmysterious or intimidating anout them, like any tool, you just have to learn how to use them correctly.
Is it a "true" acrylic?
A common misconception which I've seen on various model forums is that Tamiya's acrylics are not "true" acrylics because they can be reduced (thinned) with solvents other than water. I believe that this has come about because model paint manufacturers have put a great deal of emphasis on the easy clean up of acrylic paints using water.
The reality is that while most uncured acrylic paints are soluble in water, this is irrelevant in determining whether a paint is acrylic or not. The term "acrylic" describes a particular class of polymers (essentially a type of plastic) of a particular molecular structure, formed by the polymerisation (or joining) of smaller molecules (or monomers). Acrylic paints contain binders made up of chemicals based on these monomers. What this means is that acrylic paints don't simply dry. As the paint dries, there is a "natural" molecular attraction which causes these monomers to join together to form "long chain molecules" (aka polymers). Essentially, the paint becomes a film of "plastic". After the curing process is completed, the paint is unaffected by water.
(Apologies for the chemistry lesson - Industrial chemists and paint technologists are welcome to add comments/corrections.)
Over the years, I've seen many different suggestions for thinner for Tamiya acrylics, ranging from water to lacquer thinner. Whatever one uses, it does not change the fact that Tamiya's acrylic paints are (chemically) based on acrylic compounds, so they are undisputably acrylic paints.
What's the best thinner for Tamiya acrylics?
One of the most frequently asked questions on modelling forums is "What's the best thinner for Tamiya acrylics?"
Looking around.various forums, you will see almost everything from water, Windex, automotive windshield washer solution, Isopropyl and denatured (ethyl) alcohols, even laxquer thinner.
Despite what you may read, the best thinner for Tamiya's acrylics is Tamiya's own X-20A acrylic thinner. My understanding is that this is a mixture of Isopropyl alcohol, propylene glycol and other alcohols. It's the one which works the most reliably and consistently.
Let's look at some of the alternatives mentioned:
[ol]Water: While water will work to a certain extent, it has a tendency to degrade both the covering ability and adhesion of the paint. Push it too far and the paint will tend to bead and not stick. Also, tap water can vary considerably from one locality to another, containing dissolved minerals abd chemicals which may affect the behaviour of your paint. If you must use water, use distilled water for cosistency.
Windex: Windex is the trade name of a window cleaning product manufactured by S.C. Johnson & Co. and is available in many (but not all) countries. Windex is primarily water with a quantity of isopropyl alcohol and ammonia. While some people report successfully using Windex as a thinner, I wouldn't recommend it. The ammonia content will actually break down dry/cured acrylic paints and, I suspect, inhibits or retards the polymerization process when added to fresh paint. On the other hand, it can be useful in removing paint from your airbrush, but it must be rinsed very well with clean water afterwards as ammonia can be corrosive.
Windscreen washer solution: Some people use windscreen washer solurion. There are many different proprietary mixes, many containing (mostly) water, isopropyl alcohiol, propylene glycol and some detergents. Coincidentally, Tamiya thinner is composed of Isopropyl alcohol and propylene glycol, but in a higher concentration. I haven't tried windscreen washer solution, so I can't personally comment about its effectiveness. I rather suspect that it's only marginally better than water because the detergents act as a surfactant and reduce the surface tension, helping it to spread rather than bead.
Isopropyl alcohol: This is the primary component of Tamiya's own thinner and many people swear by it. It's often available from supermarkets and pharmacies in the form of "rubbing alcohol" at a 70% concentration. However, the preferred oprion is 90% (or higher) Here in Australia, it's much more difficult to obtain (and much more expensive, often being about the same price or more than "genuine" Tamiya thinner) than it is in, say, the United States. When used as a thinner on its own, Tamiya paint has a tendency to dry very quickly and depending on air pressure settings and distance from the airbrush to the subject, may cause the paint droplets to dry in mid-air between the airbrush and the surface being painted, resulting in a coarse, gritty finish.
Ethyl (denatured) alcohol: Ethyl alcohol is somewhat compatible with Tamiya acrylic paints. Here in Australia, it's much much cheaper than Tamiya thinner or Isopropyl alcohol, and much more obtainable. (1 litre of methylated spirits is a bit over $3.00) As a thinner for Tamiya paint, it's a little more aggressive and dries even faster than paint thinned with Isopropyl alcohol. It is "wetter" than Tamiya thinner and one can thin to a much greater degree and still get coverage where paint thinned to the same extent using Tamiya's thinner will bead and separate. I'm talking about thinning to 80% or higher thinner to paint. For certain applications, I like my paint very thin. and it works for those purposes. I do airbrush at fairly low pressures and at very close distances though.
When using either of the alcohol options above, you may wish to add an amount of acrylic retarder (available from artists supply stores. Many retarders are based on propylene glycol (another of the "main" constituents of Tamiya's paint and thinner) and extend the drying time of the paint. Also note that the alcohol options are not recommended for Tamiya's gloss acrylics, as the fast drying associated with the alcohols means that the paints may "flash dry" before a continuous smooth film forms on the paint, leading to a "dull" surface.
Lacquer thinner: Some people thin Tamiya acrylics with Lacquer thinner. "Lacquer thinners" vary quite considerably from brand to brand and may contain varying concentrations of solvents, many of which are unfrinedly to styrene. Many of the "hobby branded" lacquer thinners (reg. Tamiya, Gunze's "Mr Thinner" etc) are said to work with Tamiya paint What's the story there?
Well, I haven't tried either of these so I haven't any personal experience, but I'll make a semi-educated guess. The "hobby brand" lacquer thinners are formulated to work with paints for styrene models, so by necessity, they're less agggressive than "generic" lacquer thinners. It's said that you can leave styrene parts soaking in Tamiya or Gunze lacquer thinners with no ill effects, whereas if you try that with most generic lacquer thinners, you very quickly have a puddle of goo.
Now most lacquer thinners are a blend of alcohols and other aggressive solvents. My suspicion is that the "hobby brand" lacquer thinners contain a higher concentration of compatible alcohols and lower concentrations of the other solvents, which may explain why they work with Tamiya paints.[/ol]
Another common misconception which is often bandied about is that Tamiya paints are designed for airbrushing and can't be hand brushed, or don't hand brush very well. When they first hit the market in the early 80's Tamiya's acrylics hand brushed remarkably well. Under optimum conditions, you could brush it straight out of the bottle and when dry, they were so dead flat and streak free that it was difficult to tell they were brushed and not sprayed. Unfortunately this changed some time around 1990 and they've been finnicky to hand brush ever since, so it is true that today's Tamiya paints can be difficult to hand brush out of the bottle, but if are prepared to do a little preparation, they do hand brush rather well.
For successful brush painting with Tamiiya acrylics:
Stir the paint well.
[ul]30 seconds of shaking the bottle is pointless. Open the bottle and stir until there are no lumps or strings of paint. [/ul]
Don't paint out of the bottle.
[ul]Decant a small amount of paint onto a suitable palette [/ul]
Thin your paint
[ul] Add a small amount of Tamiya thinner, about 10%, and stir well (EDIT: Recent testing indicates that this should be closer to 30%. Take this as a starting point and adjust as required.) [/ul]
Use good quality brushes
[ul]Forget about the cheap "Dollar store" 10-on a card for $2.00 brushes, I'm talking about red sable/Kolinsky sable or high-grade Golden Taklon. Yes, we are talking a lot of $$$ but the results are worth it and when looked after properly, your brushes will last for many years.[/ul]
Put a small quantity of clean thinner in a suitable container (or another well on your palette)
Moisten your brush slightly in the clean thinner before dipping it into the paint. This "lubricates" the brush and allows the paint to flow more smoothly, both onto and off the brush.
(Dipping into the thinner, you only want it slightly moist, not wet. If you pick up too much thinner, wick it off on a paper towel or tissue.) Repeat this step every other time you "load" the brush with paint.
Brush in short, smooth, even strokes, preferably in the same direction. Only brush "back" as far as the last "wet edge". IMPORTANT: Do not brush over previously painted areas which may appear dry. Doing so will "roll it up" in ugly chunks. If you need to overcoat an area, allow it to dry and cure overnight before recoating.
If paint os starting to dry on the brush, stop for a few minutes and take the time to clean the brush. Not doing so will mean degraded btush performance, resulting in streaks and brush marks and the possibility of dry chunks of paint flaking off the bristles onto the surface you're painting.
Allow to dry overnight before painting any successive layers or colours.
Addendum:
Is it dry? It's still soft
One of the big selling points of Tamiya (and other) acrylics is the "fast drying" sspect. As I mentioned above, acrylic paints don't just dry, they cure. It's important to understand that there's a difference. Tamiya acrylics, particularly their flats, "touch dry" exceptionally quickly, sometimes within seconds of application when airbrushing. However, this simply means that the solvent has evaporated. It can take considerably longer for the paint to fully cure. During this time, the film of paint is quite fragile and is easily scratched. In the case of flats, it can be 18-24 hours before it reaches full hardness. Tamiya's gloss acrylics can take even longer due to the less permeable glossy surface film inhibiting the evaporation of the solvents (which in turn inhibit the curing process). Depending on the thickness of the application, this can sometimes take a week or more.
