If it’s necessary then how did my last tank make it 20 years without one?

What’s an expansion tank? I set it up like the old one was set up. All I did was disconnect the old one and reconnect the new one to the same pipes coming out of the wall.

I may have to try this. I have a number of outdoor projects coming up. How do you think this finish would work on furniture?

Thank you this was helpful and informative.