What is a weathering wash?

A weathering wash is a very diluted paint (typically enamel or oil-based) applied over a sealed base coat. It flows into panel lines, rivets and recessed detail by capillary action, adding depth and realism. The excess is wiped away with thinner, leaving colour only in the recesses.

What dilution ratio should I use?

The Dilution Ratio here is the number of thinner parts to 1 part paint. A strong general-grime wash sits around 5:1 to 8:1 (roughly 11-17% paint). Subtle panel-line washes are usually much more dilute — commonly 1:10 to 1:30 thinner-to-paint (about 3-9% paint), and some modellers go to a 5% paint / 95% thinner mix for the faintest lining. More dilute washes are subtler and easier to control: build up the effect with several dilute passes rather than one strong coat, and always test on a spare piece first.

How many passes of wash do I need?

Light weathering needs 1 pass. Moderate weathering benefits from 2 passes with full drying between each. Heavy weathering on armour may need 3-4 passes with different wash colours for realistic grime buildup. Always allow complete drying between passes.

Do I need a clear coat before washing?

Yes, always apply a gloss or semi-gloss clear coat before weathering washes. The smooth surface helps the wash flow into recesses by capillary action. A matt surface absorbs the wash unevenly and creates staining that is difficult to control.

ModelCalcs

Weathering Wash Calculator — Wash & Weathering Product Quantities

Calculate wash volume, pigment amounts, enamel thinner and application passes for weathering model kits.

Model ScaleLarger scales have wider, deeper recesses that hold more wash (1:48 = baseline)

Model TypeArmour and ships carry more recessed detail than aircraft or figures

Surface Area Estimate

Total surface to weather — roughly 250-400 cm² for a 1:48 aircraft

Weathering LevelLight = subtle panel lining, Heavy = grime, streaking and pin washes

How We Calculate This

This calculator gives a rough estimate of weathering product quantities based on model surface area, weathering intensity, scale and model type detail level. Washes are applied sparingly and the excess is wiped away, so the per-model volume is small — a single 30-35 ml jar of commercial wash covers many models. Treat the result as a guide for how much to mix, not an exact figure.

The formula

Wash volume = (Surface area / 100) × Base rate × Weathering level × Detail factor × Scale modifier × Capillary factor

Pigment (paint) = Wash volume ÷ (Dilution ratio + 1)

Thinner = Wash volume − Pigment

The base rate (0.8 ml per 100 cm²) and the level, detail, scale and capillary multipliers are a practical heuristic, not a manufacturer specification. The Dilution Ratio is thinner-to-paint, so a ratio of 5 means 1 part paint to 5 parts thinner — 1/6 (≈17%) of the mix is paint.

Frequently Asked Questions

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Last updated: March 2026

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