Thunderhawk Blue vs Cantabric Blue

How close are they?

ΔE 8.9, close: similar, with a visible difference side by side. Cantabric Blue is more saturated than Thunderhawk Blue.

Can I use Cantabric Blue instead of Thunderhawk Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Cantabric Blue is more saturated than Thunderhawk Blue.

Can I use Thunderhawk Blue instead of Cantabric Blue?

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

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.