here's the story so far... refinishing a neck and the clear varnish went pretty well. now doing a painted headstock. i didn't think to fill the grain as it wasnt a problem with the clear varnish on the back of the neck. but the headstock has a veneer of ash on it so you guessed it - grain is now showing thru the 4 coats of car paint primer i have just sprayed on. what do i do now? strip the primer off and start again? or can i fill the grain with something over the primer? hope you guys have a solution that is the latter. in the cupboard i have wood filler and car body filler. these any good? your thoughts and clever ideas much appreciated.