DIY Casting Concrete Pendant Lamp Shade

Casting concrete is a cheap and simple way to create custom designer household items including lamp shades. I found a simple video and blog post at BRIT+CO that describes the process using plastic drink containers and inexpensive concrete mix.

I purchased all of the lamp items from a big box home improvement store in the lighting and lamp repair section. I couldn’t find Quickrete 5000 in any local stores so I went with a more expensive fast setting high strength mix call Rapid Set CEMENT ALL. The box specifically mentioned casting so I figured I’d give it a shot. The lamp materials were:

• 3/4 inch threaded rod
• Steel hex nuts assorted sizes for light fixture repair
• 12ft lamp cord, clear
• candelabra base
• on/off switch

All of these items were found in the lighting repair section. The candelabra base is for a E12 bulb you’d typically find in a small lamp or ceiling fan lights. I followed the picture steps without watching the video nor paying close attention. Some tips I found useful had I watched the video first would be to use a bowl rather than a bucket. The round shape of a bowl would make the mixing easier. When drilling the caps leave them on the bottle. I haphazardly tried to hold and drill the cap by hand and with a vise. Wear a mask, long sleeves, and glasses when working with the mix. It’s not something you want to inhale or get in your eyes. I used large plastic Solo cups for getting my portions. The mix I used called for 4:1 mix to water. The mix sets quickly so be prepared. I used a cooking spray inside the mold to help with release. Pay close attention to the final raw edge when casting. Take the time to smooth out your top edge. I was sloppy and didn’t consider I’d end up with a jagged rough edge. Do use a metal container to hold the mold upright while it sets. The mix gets very hot.

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Rigging

The resulting concrete shade weighed in a 3.5 pounds. The weight was an initial concern, but I think it’s reasonable. I put a knot in the power cord to keep the weight off the bulb connection. Consider how you’ll mount the lamp shade before wiring the socket and shade. I made a simple post that looks the Ikea one used in the blog. Using scrap 1.5×1.5 pine I cut a post. The stain finish is Rustoleum Ultimate Wood Stain kona. Applied with a hobby sponge and wiped off with a paper towel.

I haven’t figured out where to hang it. My intent was to put it in my office, but the idea of concrete dangling from something I made scares me. My first shot at concrete casting has me thinking of new projects – cast bookends and a garden figure. I’m working out how to use the 3D printer and SmootOn casting products to make a reusable mold.