You may have noticed an influx in projects with USB hubs cast in concrete. There was a video put out by Giaco Whatever on MAKE magazine, and after it met with a great deal of criticism, several of us in the community decided to make our own version of the project in support of him. This article will take you through my interpretation of the build. I'd encourage you to watch the video!
Now, why would I want to take a USB hub and put it in concrete or cement? I aimed for making something somewhat aesthetically interesting, heavy enough not to slide around, and I wanted to make it at least a little utilitarian.
Step 1: Supplies
- Plastic Cup (will be destroyed)
- USB Hub
- 10lbs Quikrete
- Disposable Container(s)
- Hot Glue
- Miter Saw (almost any saw would be fine here)
- Hammer or Vibrating Tool
The dimensions of this project are all dependent on your USB Hub and depth/circumference of your cup.
Step 2: Constructing the Mold
I knew I wanted my hub to include a pencil cup to help organize my desk/workbench. I procured a small, plastic cup that my kid had gotten at a sandwich shop and used it as the basis for the pencil cup. I left space between the bottom and the hub, the hub and the cup, and from around the outside of the cup to the walls of the form. I didn't want there to be any chance of the concrete getting too thin and becoming weak.
I marked my pieces on some melamine scrap I had. Closet shelving off-cuts were the perfect material and size for this project. I made my cuts on the chop saw, did a dry fit, and screwed the pieces together with dry wall screws. Gluing these isn't necessary and would actually make it more difficult to de-mold later. I used some small pieces of melamine to cross over the top of the box and super glued the rim of the cup to the underside. This allows the negative form to stay level and centered.
Once I had a box, I drilled a hole for the male end of the hub to exit the box and hot-glued the main body into the corner of the box. I caulked the inside at all the joints and filled the hole as well. I figured out later that I didn't do a great job caulking and had some leaky spots. Nothing too bad, but make sure your work area is prepped for just such an occasion. If I were to re-do this project, I'd probably tape over the female USB sockets to keep them free of debris during the pouring.
Step 3: Mixing and Molding
I used a small, plastic Chinese takeout container to mix my concrete. In retrospect, it was too small and too shallow to be a good option - I spilled a good bit and ran out quickly with each batch. However, using such a small amount at a time, I was able to keep it from getting too wet too quickly. I used a free paint stick from the home store to stir and kept on a glove to keep from burning my skin. I tried to maintain an even consistency somewhere around oatmeal - not too runny, not too dry. I owe a great deal of the success with the mixture to the Concrete Instructables class. I'd have poured soupy cement, otherwise!
I poured the concrete mix in the form, using my hand and the stirrer to pack it in. As it got full, I tapped the form on the table and also tapped it with a dead blow hammer. I'd pre-drilled the brace for the pencil cup and screwed it back in where it'd been test-fitted. Another thing I'd change would be to get the form over-full and scrap the top flush. I'd also add some ballast to the cup to help it hold its shape - I had issues with the weight of the concrete wanting to push in the sides of the empty, thin-walled cup and keep it from being round, but I was able to persuade it back into shape before the concrete set.
Step 4: Demolding and Finishing
I was terrified that I'd wasted my time and concrete, thinking I'd open the form to find a crumbly mess. I let the project cure for 4 and a half days. I removed all the screws and used a thin electrician's knife to pry apart the boards. At this point, I remembered that I'd intended to do a mold release with some non-stick spray, but had forgot. Luckily, with the melamine, I was fine! The sides came off fairly easily and the concrete was smooth! Removing the caulk and hot glue was interesting, but not too difficult.
I finished off with some 220 grit paper, by hand, just to knock the sharpest edges down and smooth the rough spots in the corners. You can see in the photos how smooth the flat surfaces came out, but where the concrete rested against the caulk, it stayed rough. My guess is that the silicone, being squishy, didn't give enough resistance to the concrete. Perhaps epoxy would be a better material for the corners, but would probably make it more difficult to disassemble.
Step 5: Complete
I chose for my cement USB hub to function as:
- Desk Art
- Pencil Cup
- Hood Ornament
- Alien Monolith
- Melee weapon
- USB Hub
It's also been a nice spot to rest my phone. Since it's higher than desk level, I'm not having to look down to see notifications or check the time. I originally wanted to inset a negative form to act as a phone holder, but didn't have the confidence in my concrete skills. There's definitely enough room in my 10lbs USB hub! Another idea I'd like to try out in the future would be running some kind of small pipe through the form and using that as pencil/brush/marker storage.
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