Great project but I echo what's been said. Hammerite/Smoothrite is ****e for painting parts like that. Not only is it much tinner than it used to be but it also chips and flakes badly. You'd be much much better using a proper chassis paint. I'm using Tetrosyl Chassis Black thinned down 10 - 20% then strayed with a compressor and it's so so much better than the Smoothrite I tried first. Trust me, it'll be worth it in the long run plus it's a feck load cheaper too!