Yes it will work – for a little while if my experience is anything to go by.
I built a 3" traction engine and soft soldered all the joints. And after they failed in less than a month, I had to replumb the whole thing. I don't think I have a single original joint remaing.
So I would stronly advise you to forget the soft solder – unless you enjoy plumbing.
Comsol might be OK – no exerience, but personally, I have no intention of putting soft solder anywhere near a steam pipe again!