but the first coat bonds to the plasterboard ???

On Tuesday, June 4, 2019 at 8:43:13 PM UTC+1, Andy Burns wrote:
George Miles wrote:

Today I'm using orange packets of thistle multifinish over
plasterboards. Most videos show a skim coat a few hours after the
first, but why not tomorrow?

I'm no plasterer, but I thought it would go off too much for the final
coat to bond well if left e.g overnight?