Allen Head bolt Anti-theft?

I am currently building up a bike with (in my opinion) expensive quill stem and handlebars. I sometimes need to park it outside. I am currently experimenting with different adhesives in the head of the allen bolts to deter theft. I've heard people using epoxy with a ball bearing, but acetone to remove the epoxy makes me nervous with painted surfaces around. Bathroom Caulk seems to be rather easy to remove. I'm aware of expensive anti-theft bolts, but I was looking for an easy/cheap fix. Any Suggestions/ Ideas?