Slotted Concrete Planter

Enhance your indoor space with this stylish small planter featuring a cast concrete veneer. Designed with functionality in mind, the soil remains separate from the concrete, preventing any pH imbalances caused by lime. This makes it a perfect choice for all indoor plants. Additionally, the casting method ensures proper drainage, promoting healthy plant growth.

What to print:

• Mold Slot X 1
• Mold Slit X 1
• Drain Riser X 1
• Printed Top X 1. 
• 61mm Water tray (optional)

Extras:

• Cooking oil
• Painters tape
• Binder Clips
• Concrete/Cement/Mortar/Grout. I suggest Cement All Multi-Purpose Construction Material & Non-Shrink Grout
• Filler-primer(optional)
• Filler Resin(optional)
• Something to vibrate the mold with. Like an orbital sander (optional)

How To Print:

Printed Top:

• Orientation: Print with the drain hole facing the print bed. This requires significant support, but since the interface side will be covered in concrete, aesthetics in that area are not a concern.

Recommended Print Settings:

• Filament: Any material you find aesthetically pleasing
• Layer Height: 0.15mm or less
• Nozzle Size: 0.4mm
• Infill: 10%
• Walls: 2

Mold:

• Orientation: Print with the closed bottom on the bed. No special considerations are needed.

Recommended Print Settings:

• Filament: Any
• Layer Height: 0.2–0.3mm
• Nozzle Size: 0.4mm
• Infill: 10%
• Walls: 2

Drain Riser:

• Orientation: Vertical, no special considerations are needed.

Recommended Print Settings:

• Filament: Any
• Layer Height:  .2-.3mm
• Nozzle:  .4mm
• Infill: 10 %
• Walls: 2

Assembly & Prep Instructions

Assembling the Drain Riser

• Once all pieces are printed, glue the drain riser into the recessed slot on the underside of the planter top.
• Allow the glue to fully dry before proceeding.

Prepping for Casting

• Apply painter’s tape over the slotted area of the top piece to make cleaning up any flashing easier. Cover about half of the slotted section.
• Place a small piece of painter’s tape over the drain hole to prevent seepage.

Smoothing the Mold (Optional)

• If desired, apply a filler-primer or resin to the mold to minimize visible layer lines. This step is optional and purely aesthetic.
• Allow any applied filler to dry completely before continuing.

Applying a Release Agent

• Generously coat the inside of the mold with cooking oil to ensure easy release. The oil should be thick but not pooling.
• Do not apply oil to the planter top.

Casting Steps

Positioning the Planter Top

• After assembling the top and prepping the mold, place the planter top into the mold with the drain side facing up.
• If the fit is loose, use a small amount of hot glue to secure it in place.
• Align the planter top’s pillars with the mold’s seam—this helps prevent visible seams in the final casting.
• Double-check that the drain hole is covered to prevent the planter from filling with concrete.

Closing the Mold

• Carefully close the mold around the planter top. It should fit snugly.
• Secure the mold using binder clips or quick-release clamps to keep it tightly closed.

Mixing and Pouring the Concrete

• Prepare your concrete mix according to the manufacturer’s instructions. I recommend Cement All fast-setting all-purpose grout, but any fine mix without large aggregates will work.
• Avoid making the mix too runny, as this can result in weak concrete, slow curing, and cracks during drying.
• Slowly pour the mixture into the mold, stopping just at the circular cutout at the top.
• If possible, use a vibration tool to remove air bubbles and ensure the concrete settles properly.

Demolding

• Allow the concrete to set until it is firm but not fully dry—it should be hard enough to resist a fingernail press but still slightly pliable.
• Gently pry open the mold using an old butter knife. One side will usually release more easily than the other.
• Insert your fingers into the planter for support, then tap along the inside edges of the mold to fully release the casting.