This is a Collodion Silver Nitrate Tank. The design holds a bit less than 1 Liter of Silvernitrat.
Thats good for plates up to 18 cm x 24 cm.
You need Plexiglas of the following sizes:
2 pieces of 20cm x 26 cm
2 pieces of 2cm x 26cm
1 piece of 20cm x (2 cm + 2 x the thickness of your plexiglas)
Note that the final measures vary by the thickness of your plexiglas. I recommend using 3mm. So it depends a bit on the thickness of your plexiglas. You can cut the plexi with a normal (fine) band saw that you would otherwise cut plywood with. CA glue (Cyanacrylate) is pretty much the only glue that you can use for plexiglas.