TIP FOR THE DAY:
PREPSOL.
Prepsol is a wax and grease remover. Normally, I would prepsol a paintjob before laying basecoats - however today for some stupid reason, I decided I didn't need to.
Start laying paint - BANG - a thumb print.
Our body oils are one of paints natural enemies, along with dust we carry in on our skin and clothes. We can't see the oil we spread when we handle things, yet when the paint hits the oil, its doesn't like it. Becomes clearly visable, also means theres not 100% adhesion in the contaminated spots which could cause paint failure in the future..
The fix: sand back and do it again.
The prevention : Prepsol.
Prepsol has it's own devils. You need to wipe it on with one rag, wipe it off with another rag, as you also need to get all the prepsol off or it'll create its own non adhesion contamination.