Stackable lightweight shelf system. Feel free to print as many rows and columns as you need. 

Assembly

Shelves need to be glued together (apart from single version). Use glue of your choice according to material used. For PLA, clear epoxy works for me really well.

There are 4 files, the difference is in thickness of side support structures:

• shelf single - both sides thick, usable as single shelf or for vertical stack of shelves
• shelf middle - both sides are thin, glue to another middle shelf or left/right shelves for sufficient load capacity
• shelf left - thick left side, thin right. Needs to be glued with middle of right version to have sufficient load capacity
• shelf right - thick right side, thin right. Needs to be glued with middle of left version to have sufficient load capacity

Print settings

• PLA or other rigid material
• No supports 
• At least 20% infill
• 0.5mm nozzle seems to work the best for default size but other sizes are OK as well