Thunderhawk Blue vs Sea Blue

How close are they?

ΔE 8.2, close: similar, with a visible difference side by side. Sea Blue is warmer than Thunderhawk Blue.

Can I use Sea Blue instead of Thunderhawk Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Sea Blue is warmer than Thunderhawk Blue.

Can I use Thunderhawk Blue instead of Sea Blue?

The same difference applies the other way round: Thunderhawk Blue is cooler.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.