Weathering Wash Calculator — Wash & Weathering Product Quantities

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.

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.

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.

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.