I didn't have this problem with the original hot end but my new E3d v6 hot end has a nozzle that seems to have a mind of it's own. It literally unscrews itself during each print destroying the printed object. I tighten it down but I'm afriad to over crank the wrench and break the nozzle. I thought about using something like Loctite but I think that would make it difficult to switch out nozzle tips. What should be used on nozzles?