What is the best wash type for panel lines?

Enamel washes are widely regarded as the most controllable for panel line work because they remain workable for several hours and excess can be removed cleanly with white spirit without disturbing the underlying acrylic base coat (provided the base is fully cured under a gloss clear coat). Oil washes offer even longer working times. Acrylic washes are safer to use (no solvents) but dry quickly and are harder to remove cleanly.

Why do I need a gloss coat before washing?

A gloss clear coat creates a smooth, non-porous surface that allows the wash to flow freely by capillary action into recesses rather than being absorbed by a matt base coat. Without a gloss coat the wash will stain the surface unevenly and be almost impossible to remove cleanly. Apply a gloss coat and allow it to cure fully — at least 24 hours for solvent-based clears — before applying washes.

How does scale affect wash quantity?

Larger scales have physically wider and deeper panel lines at the model surface. A 1:35 AFV has panel lines roughly twice as wide as the equivalent 1:72 aircraft feature. Wider lines hold more wash by volume, so you need proportionally more wash on larger scale models to fill the recesses sufficiently.

What paint-to-thinner ratio should I use for a wash?

There is no single correct ratio — it depends on the effect. As starting points: a panel-line or pin wash that needs to flow into recesses and stay put is usually around 1 part paint to 3–5 parts thinner; a general all-over wash is roughly 1:4 (about 20% paint); and a very thin filter-style wash that subtly tints the surface can be 1:10 to 1:20 (5–10% paint). This calculator defaults to enamel 1:12, oil 1:8 and acrylic 1:6, but the Dilution Ratio Override lets you dial in any value from about 1:3 to 1:30. Mix thinner than you think you need and build up — you can always add more paint, but an over-pigmented wash stains and is hard to remove.

How do I remove excess wash without damaging my base coat?

For enamel washes, dampen a cotton bud or flat brush with white spirit or odourless enamel thinner and gently stroke along the surface away from the panel lines. Never scrub. For oil washes, use the same technique while the paint is still pliable. For acrylic washes, work quickly and use a clean damp (not wet) brush. Always work in the direction of panel lines to leave residue where it reads most naturally.

Weathering Wash Mix Calculator — Paint-to-Thinner Ratio & Volume

Calculate the exact paint-to-thinner ratio, total wash volume, drying time and number of coats for oil, enamel and acrylic panel line washes.

Model Surface Area

Rough surface to be washed (only sizes the batch estimate) — a 1:48 aircraft is typically 250–400 cm²; a 1:35 tank around 300–500 cm²

Model ScaleLarger scales have wider recesses to fill, so the batch estimate scales up — 1:16 needs roughly three times the wash of 1:72 for the same surface

Wash TypeSets the typical starting dilution and drying time — enamel is most popular for panel lines as it stays workable and lifts off cleanly with white spirit

Panel Line DensityHow much engraved and recessed detail the model carries — heavier detail draws in more wash, so the batch estimate goes up

Number of CoatsHow many passes you plan to build up — kept separate from line density so a single factor never inflates the total twice. Most work needs 1–2 coats

How We Calculate This

The dependable part of this calculator is the dilution split: for any total volume of wash you want to mix, it works out how much paint and how much thinner to combine for a given paint-to-thinner ratio. That maths is exact.

The total volume figure is an indicative planning estimate — a way to size a batch so you mix enough to finish a session without running short. There is no industry standard that meters wash by surface area: in practice you thin to consistency by eye and apply until the panel lines fill. Treat the millilitre total as a rough guide, not a precise requirement, and mix a little extra.

The maths

Estimated batch (per coat) = (Surface area ÷ 100) × Density rate × Scale factor

Total wash = Batch per coat × Number of coats

Paint volume = Total wash ÷ (Dilution ratio + 1)

Thinner volume = Total wash − Paint volume

Paint in drops = Paint volume × 20 (a standard dropper delivers ≈ 20 drops per ml, i.e. 0.05 ml per drop)

Density rate — rough batch sizing, 0.4 ml/100cm² (light lines) to 1.4 ml/100cm² (heavy detail). Indicative only.
Scale factor — 0.7× at 1:72 up to 2.0× at 1:16, because larger scales have physically wider recesses to fill.
Dilution ratio — typical starting points: enamel 1:12, oil 1:8, acrylic 1:6 (paint:thinner). The accepted range is wide — panel-line and pin washes run roughly 1:3 to 1:5, general washes about 1:4 (20% paint), and very thin filter-style washes 1:10 to 1:20 (5–10% paint). Use the ratio override to dial in your own effect.
Number of coats — your choice; density no longer secretly multiplies the coat count, so heavy detail and many coats are independent decisions.

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Always verify quantities before purchasing materials.