Weight
Table 1: Weights and nominal capacities of typical metal beer casks.
CASK.......... NOM CAP Litres (Imp Gal)............MATERIAL
Firkin...... ........ 41 (9) ........................... Stainless Steel
Kilderkin ........ 82 (18) ......................... Stainless Steel
Barrel ............164 (36) ......................... Aluminium
Keg - Wikipedia
Jump to Beer keg - Beer keg. Beer kegs are made of stainless steel, or less commonly, of aluminium. A keg has a single opening on one end, called a "bung."
Yes, me too. I would use that one for the outlet. How about stand it on end, weld up the side outlet, use the bung for the filler, tap small holes for fittings.