Concrete lamp pendant mold. (2025 update!)

New design: The center is slightly tapered so hopefully its easier to get out, and the shell is redesigned to use screws and nuts to make sure it's stays securely locked together, instead of relying on rubber bands or string.  

You will need following things to make this:

• Cement (duh)
• Light-socket. I designed it for a E27 socket
• Cable (and heat shrinkable tubing if using fabric covered cable. To “terminate” the endings of the fabric)
• A light bulb 
• 6 x m5 machine screws and nuts
• Patience!

I also recommend some kind of releasing agent. I foolishly tried using a balloon stretched over the central part. Inspired by the concrete planters by Alexandre Chappel. But it had little to no effect for me.

After curing for about a day; the outer shell can be taken off. After about at least two days of curing, the “plugs” can be drilled out, or maybe be removed with the aid of a heat-gun? The center piece can also be removed at this time (Likely requiring violence, if no release agent was used).

You'll need to print 3 x shells and 3 x plugs. 
The plugs should slot into the hole in each of the shells.

The red print pictured is the old design, the black is the new one.