Plate boxes can be made from scratch. This example is a metal card file modified to hold the plates. If the plate box will hold sensitized plates, the box should be light tight.

This plate holder is for buffing with the motorized wheel and the hand buff. A layer of formica with a window the size of the plate was glued to a piece of plywood.

.

This is a holder that slides or drops into a box for fuming or mercury developing. The material is polycarbonate.

A vicegrip is handy to hold the plate over a heat source for drying