I used silicone bronze to TIG weld/braze sheet metal sections when I was raising the roof. I am not a pro welder especially when it comes to TIG.
It was so easy to control flow and fill gaps and dents here and there using silicon bronze. This is why I was thinking about using it when tig weld stainless tank.
My crawl space is 24" high and almost 8' wide. But there is a frame in the middle. This makes middle section not very useful.
I was thinking to fit tank between frame rails (24"Wx32"Lx24"H) and have the rest for storage. This would give me almost 80 gallon tank in almost useless space.
I can add another grey tank in next frame rail section which is even longer about 36" (almost 90 gall tank)
Also I can add connections I like where I like.
Here is a price:
I can see a bunch of 40 gall tanks on eBay at about 200 USD. Quality??? I have no idea, shape I don't like because they are almost flat...
I will pay just over 100 CAD (75 USD) for 4'x8'x 14 gage 304 stainless. Filler rod will be another few bucks and labour is free.
Grey tanks are different story I can see many of them "cube" shaped. I can even stack them and cascade connect them. This will be almost like a septic field...
When it comes to fixing the tank you can fix them all. metal cal be glued using epoxy or soldered/ brazed, ABS plastic solvent glued, PE plastic welded.
I am thinking about adding a Sewage Pump into tank but will think about it what pump type to use.
Hey just found this very educating video: