Copyright 2018 Richard Fay
I have been building guitars in the UK for about 25 years and started doing swirl paint finishes in the early 2000's. I was in business for a few years doing them around 2005-8 and then started again in 2017.
Swirl finishes are applied by floating the paint on water and slowly pushing the guitar in. So although there is some control, it is also largely in the lap of the gods, and every one is unique!