For 4 tubes to process 4x5 sheet film, you will need the following. For 5x7 or 8x10 sheet film, go for a larger diameter pipe in longer lengths, just scale it up.

(4) 6" sections of 2" diameter schedule 40 black ABS wastewater pipe. This should be completely opaque. The lighter colored PVC pipe meant for fresh/potable water may be too translucent and contribute to fogging. The hardware store will likely stock this in 8-10' sections. Buy one, have them cut it in half so you can fit it in your car, then cut them to length at home with a hacksaw.

(8) endcaps of 2" ID black ABS to seal one end of each tube

(4) black ABS couplers, of the type that glue onto the pipe and provide male threads

(4) black ABS couplers, of the type that have female threads to fit the couplers above, going to a glueable 2" dia to glue one of the endcaps on.

1 small can of ABS cement to glue the pipe bits together with

1 sheet 320 grit wet-or-dry sandpaper

1 sheet 400 grit wet-or-dry sandpaper

penknife