Concrete Phone Stands, 3D-Printed Mold

This is the 3rd version of the concrete phone stand.

The previous version involved a PVC pipe, wood inserts, and complex cuts into a PVC pipe. The first version used a Tupperware box.

The quality of the concrete surface is always directly dependent on the mold surface.

This version still involves a PVC pipe, and uses 3D-printed inserts, enabling easy production of molds, for example for workshops. It has a swappable logo plate.

With a mold, one phone stand can be produced in ca. one noon break, at your office!

Step 1: Mold Concept

The mold consists of the following pieces:

• PVC pipe for the outer shell.
• Skewed plate, forming the plane on which the phone will rest.
  A small piece is attached with a screw, to close the "nose".
• Cavity mold, creating the cable cavity, and cable roll storage. It has arms to form a cross, in order to make a precise positioning into the PVC tube.
  A closing lid adds rigidity, and is inserted into a grove of the cavity mold. When the lid is removed, the cavity shape can be squeezed for easier demolding.

Step 2: Make the Parts

3D printed parts:

Print each of the 4 STL files embedded in this step. They match a PVC pipe with 10 cm inner diameter.

• 1-top.stl -- skewed plat
  
• 2-top-rest.stl -- to be attached to 1, using a screw
  
• 3-top-label.stl -- logo to be snapped into 1
  
• 4-bottom.stl -- cavity mold, with its lid

For source files in OpenSCAD format, see my GitHup repository.

PVC pipe:

Take a PVC pipe of 10 cm inner diameter, and cut it to a height of precisely 13.5 cm.
Carefully make a vertical cut, to ease later demolding.

Step 3: Gathering Parts for a Kit

Kit:

Able to fit in one box:

• A soup spoon, for concrete powder
• A spatula, to mix the concrete
• A brush, to apply grease
• A rubber bowl, to mix the concrete
• A bowl for water
• A small jar of grease
• A small jar of concrete sealant
• Masking tape

Concrete:

Another box with fine (sieved, if needed) concrete.

Additionally you can use concrete pigment in powder form, to give it a desired tint.

Step 4: Assembling the Parts

1. Tape the PVC pipe.
2. Apply the logo inside the top part (skewed plate). Mind the orientation!
3. Fit the top part into the pipe. Note: the mold is upside-down, so the top part is now at the bottom.

Step 5: Applying Grease

1. Apply grease on the inner side of the PVC Tube and on the inner side of the skewed plate.
   ADVICE: To make what will become the top edge less sharp and breakable, fill the bottom with some grease, and carefully spread to form a nicely rounded fillet.
2. Assemble the two parts of the cavity mold together, and liberally spread grease on its surface.
3. Position the cavity mold on the PVC pipe. Carefully align it to the "nose" of the skewed plate.
4. Tape the cavity mold to the PVC pipe.

Step 6: Mixing and Pouring the Concrete

1. Pour concrete into the rubber bowl, and progressively add water while mixing. Not the other way round!
2. Obtain a smooth and creamy mixture.
3. Pour into the mold. The concrete surface should just not touch the arms of the mold.
4. Shake/vibrate to remove bubbles.

Step 7: Waiting...

After 3 to 4 days, check if the concrete is cured and dry. But to be absolutely safe, wait one week.

Step 8: Demolding and Priming

1. Carefully demold.
2. Rectify edges and bottom side with sand paper (wet). Let dry.
3. Apply concrete sealant to glue the sand grains together and keep the surface smooth while aging.

Step 9: Optional: Make a Protective Pad

This optional step will ensure protection of the surfaces, and avoid wiggling.

1. Wet-sand the bottom side of the stand.
2. Cut out a protective pad in a 3-5 mm thick MDF sheet, and glue it on the bottom.

SVG file for laser cutting will be added here.

Step 10: Finished Product

This is the finished product.

You can optionally spray-paint it, or leave it natural.

For the one on the photo, a fair amount of pigments for concrete was added in step 6.

Love it? or still unsatisfied with the results? Make more!