Any serious plastics dealer in any major city can sell you all kinds of sheet goods. But then you'd still have to come up with the caps, and they do have to fit perfectly or you'll get both a light leak and chemical leak. Preformed pipe would be a lot easier to deal with. But having a plastic
which solvent-welds with glue makes life a lot easier than having to heat-weld things together. And some plastics fabricate a lot easier than
others too. If a big drum becomes especially heavy when it is filled, you just need a little heavier gearmotor to drive. ... and I don't mean those tiny little things like they put in a Jobo. Just remember that your rinse volumes should be quite a bit more than what you need to simply
develop a print, and that any cap design needs to allow you to fill and drain your chemistry very quickly.