Which Airbrush Thinner Do You Need? Start With Your Paint Type.

For waterborne acrylic lines, use the acrylic thinner or airbrush medium named for that product. These products are formulated to reduce viscosity while preserving the line's binder system, but "acrylic" alone does not tell you the carrier: some acrylics are waterborne, while others are alcohol- or solvent-based and need the maker's reducer. Read the label before choosing a thinner.

Some waterborne acrylic labels allow water; others call for a proprietary thinner or medium. Follow the exact label for the paint line you are using, and test a small mixture on scrap before spraying a model. Check how it sprays, levels and adheres under your conditions rather than assuming water and the maker's thinner behave the same. A medium from a different brand is not automatically compatible.

Published examples, not universal ratios. Vallejo's Model Color airbrush guide gives one named basecoat — Field Blue 70.964 — as two parts 71.261 Airbrush Thinner to two parts paint (1:1 thinner:paint), then three drops of 71.262 Flow Improver per ten drops of paint, with the drops counted against the paint. Vallejo guide (PDF) Createx's Wicked Colors sheet gives 10–30% reducer depending on colour and tip, around 10% at a 0.5 mm tip, Transparent Colors at 25–30 psi and at least 10 minutes' acclimation — for that line only. Createx Wicked Colors TDS (PDF) GOLDEN's High Flow sheet notes that some pigments are unsuited to fine nozzles or fine tips, which is a line-scoped limitation rather than a rule about all craft acrylic. GOLDEN High Flow sheet

Iwata's paint guide recommends Medea products for water-soluble paints and directs readers to the paint label or manufacturer for other materials — a maker recommendation for a product family, not a universal thinner rule. Iwata paint guide

Lacquer thinners are strong organic solvents. They produce noticeable fumes, so adequate ventilation is required before spraying lacquer through an airbrush — a spray booth, open garage, or outdoor space. Drying and recoat timing depend on the actual paint, thinner and conditions; some products are formulated for extended working time. Follow the exact maker's reduction and recoat instructions for that lacquer line rather than assuming a universal drying speed.

Humbrol enamel paints are paired by the maker with Humbrol Enamel Thinners, and Revell enamel paints with Revell Color Mix. For the enamel ranges from AK Interactive and AMMO of Mig, use the thinner named for that specific range; a compatible mineral spirit may be an option where the maker says so. Solvent chemistry can overlap across acrylic, lacquer and enamel categories, so match the exact paint line and thinner rather than relying on the family name. Water is not a substitute for these solvent-based enamels.

Enamel lines are often formulated for a longer open time than many acrylics and lacquers, which can be useful for brush blending and pin washes but requires patience at the airbrush. Drying and recoat times vary by product, so follow the label for the exact enamel line. Fumes from enamel thinners are noticeable, so ventilation is required.