Nail polish works just as well.

Eugene Wendland wrote:
Does anyone know what compound is used to secure the nuts and threads on
aviation engines? I'm not talking about loctite, but the compound that is
placed on the outside of the nut and then onto the threads. Usually, it's a
very visible colour and laid in a straight line so that one can visually see
if a nut or bolt has backed off. I've seen it done with silicon, but I'm
wondering what the real hard compound is. Any suggestions?

Thanks

Gene