Just out of curiosity because I suspect my country is crazy expensive compared to most others, how much is welding gas where you live? In sweden, a rent-free 8L Argon bottle costs roughly £470 for the initial purchase, and then it's another £90 every time I want to have it refilled/exchanged. Because of this, I've actually chosen to try and opt out of the Swedish flask exchange system and instead import my gas bottles from Poland. I can get a full 8L bottle sent here for around £100 including shipping, and if it's made from aluminium which I suspect I can just melt it down once it's empty and use for my casting hobby. That'll save me roughly £20 in not having to buy the scrap aluminium from the scrapyard which brings my total down below the cost of a flask exchange (which is pretty insane if you ask me)... What's the situation like where you live?