I sympathize with you DarrenT. Things like copper, aluminum, and brass should never be left alone unless they are VERY secured. That kind of nonsense happens alot on job sites... even the wood gets stolen, more so after a hurricane season has jacked up prices of wood. It's worth it to look into renting an on-site storage locker that can be placed on your property. Get a ROUND padlock that makes hammers and prybars slip off of it. Some trucking outfits will drop off a container/locker for a monthly fee. You can lock everything in it then, even your tools. I'm doing that at present, while I am remodeling my garage/workshop. Wouldn't you know that despite having two shackle padlocks on the latch, a thief hammered one off. The larger one held in place, thank God! Now, there's a round padlock on it!! They haven't been back.