I'm helping a friend of mine rattle can paint is crash bars and exhaust heat shields.

I noticed the paint was dry to the touch after a couple of hours but one of the heat shield fell on the ground and got scuffed rather easily so my question is do I have to give it more time to cure and harden or do I need to spray some kind of clear protective coat over it

We used vti header paint for the exhaust which says it can withstand up to 2000 degrees heat.

The crash bars and lower legs were just gloss black.

All came out nice considering rattle can, just want to make sure it holds up somewhat decent.

 

The only sure thing for certain parts will be power coat, but if you're looking for a quick fix, you probably went the best route with the high heat paint. Adding a clear coat won't necessarily make it much more resistant to drops or scrapes, but it will help a little. SprayMax makes a catalyzed clear coat in a can. It's the next best thing if you're not tooled for traditional painting. It's a little pricey, but it does work well. You have to make sure it's compatible with the base coat, or it might lift. Read all the documentation before you pull the trigger.

http://www.spraymax.com/index.php?id=361&L=1