Old hot water tanks for thermal storage?

I have access to alot of free electric hot water tanks is it a good Idea to plumb these together and use them for thermal storage? (In my case I am just trying to add capacity)

Can't hurt, in my opinion. As long as they don't leak. I probably wouldn't use them for pressurized storage though. Just a bunch of hassles that go along with pressure vessels. Each one should have expansion to go along with it i would think.

just know that they will most likely have lots of lime and gunk in the bottom that you may be introducing to the system.
karl

I'd be a bit leery - questionable water quality can really put a kicking into a DHW tank. They are typically used under higher pressures than a storage setup (like, twice as much), but not temperatures that are as high.

Any 110 gallon propane tanks around you? There's a mountain of them an hour away from me. They fit almost anywhere, 30" diameter x 4ft. tall.

Based on the comments here I will just stick to propane tanks. No need to risk using old DHW tanks if one were to fail that is alot of water that would be in my basement. I just need to find some good deals on old propane tanks they are neot that easy to find around me. I can travel about 3 hours and get them though.