Loctite 242 (blue)is a medium strength thread locker. There is a good chance it would have to be heated to release.
Loctite 271 (red) is a high strength thread locker. It WOULD have to be heated to release.
Loctite 221 and 222 (purple) are interchangeable and are both low strength and hard to find. They are, however, what you want.
I got mine on Amazon.com and the shipping was more than the product.