Ray Mar Art Supplies makes these great wet panel carriers for plein air painters. Unfortunately they’re only available in inches. I tried to get Sandro at Zecchi to make them with centimeter sizes but no dice. Since I’m about to go painting on a boat for a week I decided to make my own with that hollow plastic sheeting they sell at hardware stores, and I just copied the Ray Mar design (actually my wife figured it out, I discovered I can’t visualize a 3D object as a flat shape).
Here are few pictures of it:
And here is the design, for 20 x 30 cm panels, if anyone wants to make their own. I just sealed it up with electrical tape, and made the slots from slices of the plastic sheets. I would get a medium thickness for the plastic, the one I used was the full-sized one and it’s too thick. Also, next time I would rip up an old CD case for the slots to hold the panels.