I currently purchased a custom copper pen. My problem is that it tends to come loose at the part where it opens up to replace the refill. Its threads are copper and I was thinking of maybe putting loctite on the threads? Would that be a bad idea? Would it ruin the copper or whatnot?

I want something that I can easily open it up again if needed to replace the refill. So something not strong enough to be permanent. What color of loctite do you guys recommend? Or do you have any other suggestions I could do to lock the threads?

Thank you!