DIECASTVAULT

Weathering Wash Ratio Calculator

Enter a paint-to-thinner ratio and the volume you want to mix, and get the split in millilitres and dropper counts for a consistent, repeatable wash.

A pin wash is usually thinned much further than a base coat — 1:3 to 1:6 paint to thinner is a common starting range for panel lines.

~20 drops/mL is typical for thin liquids; recalibrate with your own dropper for precision.

Wash mix

Ratio
1:4
Paint
2 mL
Thinner
8 mL
Paint drops
40
Thinner drops
160

How the mix is calculated

The calculator splits your target volume across the ratio's two parts, then converts each part into drops using your dropper's rate — about 20 drops per millilitre is typical for a thin, wash-consistency liquid, though a viscous mix or a different dropper size will vary. Recalibrating the drops-per-mL figure by counting how many drops it actually takes to fill a syringe to 1 mL gets the conversion accurate for your own tools.

Mixing to a fixed ratio rather than eyeballing consistency means a wash you liked on one model can be reproduced exactly on the next, and lets you note down a favorite ratio per paint brand for future reference.

Frequently Asked Questions

What ratio should I use for a pin wash?

1:3 to 1:6 paint to thinner is a common range for enamel and acrylic panel-line washes — thinner mixes flow into recesses more readily but carry less pigment, so you may need a second pass. Heavier washes (closer to 1:2) suit larger-scale models where you want more visible depth in the lines.

Why does the calculator convert to drops instead of just millilitres?

Wash volumes are often too small to measure accurately with a syringe alone, especially for a single panel line touch-up. Counting drops from a dropper or pipette is far more precise at this scale — the calculator assumes about 20 drops per mL for a thin liquid by default, but you can recalibrate it to your own dropper.

Does this work for oil-paint washes too?

Yes — the ratio math is the same whether you're thinning an oil paint with odorless mineral spirits, an enamel with enamel thinner, or an acrylic with water or acrylic medium. Oils and enamels typically dry slower, giving more time to wipe back excess before it sets.

Educational tool only. Actual flow and drying time depend on your specific paint, thinner, and ambient humidity; test a wash on a spare part or hidden area first.