Yes, J-B WELD does go bad. Here in the desert SW anything with a solvent or resin in it is short-lived, usually 1 year or less. This is true even if it is kept in a refrigerator, but the cool does extend the shelf life quite a bit. The humidity may get as low as 5%. Fiberglass resin will turn sort of purple. At this stage it won't cure properly so you may as well throw it in the trash. All of the above mentioned problems are with new, never-opened containers. We always buy everything of this nature in small containers to save $$$.