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DIY & Home Improvement ⚡ Intermediate ⏱️ 4 hours active (plus 24 hours curing)

How to Cast a Concrete Apple Logo Display

Cast a durable concrete Apple logo display base equipped with custom-molded wells for a protected iPhone and soda bottles to stage high-energy fizzy science geysers.

Quick answer

This guide shows how to cast a concrete apple logo display in 4 hours active (plus 24 hours curing). Start with carve the apple logo mold negative; follow the safety notes and step checkpoints below.

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🧰 Required Tools & Equipment

  • ✓ Utility knife with fresh blades
  • ✓ Trowel and mixing bucket
  • ✓ Hot glue gun
  • ✓ 120-grit and 220-grit sandpaper
  • ✓ Drop cloth or plastic tarp

📦 Materials & Supplies

  • ✓ Rapid-setting fine concrete mix
  • ✓ 2-inch thick XPS foam board
  • ✓ Mold release spray or petroleum jelly
  • ✓ Assorted sodas (Coca-Cola, Fanta, Mountain Dew) and Mentos
  • ✓ Waterproof sealed phone display case

⚠️ Safety Checkpoints & Warnings

📋 Step-by-Step Guide (6 Steps)

1

Carve the Apple Logo Mold Negative

Trace a large Apple silhouette with the iconic leaf and bite onto a sheet of XPS foam board. Use a sharp utility knife held at a 90-degree angle to cut clean, vertical edges along the stencil lines. Create recessed negative cutouts in the foam sized exactly for the waterproof phone case and the bases of your soda bottles.

👁️ Camera AI Checkpoint
  • • Smooth vertical foam edges resembling the Apple logo
  • • Custom foam pockets that match the diameter of the soda bottles and phone case
🛑 Watch Out For
  • • Cutting at a bevel, which makes the cured concrete difficult to demold cleanly
  • • Making the bottle cutouts too tight, preventing easy insertion of soda bottles
⚠️ Safety Note: Always cut away from your body and keep your free hand behind the cutting path.
2

Assemble and Seal the Casting Form

Affix your carved foam Apple logo and bottle core plugs to a flat melamine or plastic baseboard using hot glue. Build a perimeter retaining wall around the logo using rigid foam strips or plastic flashing to contain the pour. Apply a thin, even coat of mold release spray across all interior surfaces and foam inserts.

👁️ Camera AI Checkpoint
  • • Perimeter walls completely sealed at the base with no light visible through gaps
  • • All interior foam coated with a light sheen of release agent
🛑 Watch Out For
  • • Using too much hot glue on contact surfaces, creating lumps in the final cement face
  • • Skipping release spray, which causes foam to tear and adhere permanently to the concrete
⚠️ Safety Note: Avoid touching hot melt glue directly to prevent minor burns.
3

Mix and Pour the Cement Matrix

Combine the fine concrete mix with water in a clean bucket according to package directions, aiming for a thick pancake-batter consistency. Slowly pour the slurry around your foam core elements, filling the mold completely to the top edge. Firmly tap the sides and base of the casting form for two minutes to vibrate trapped air bubbles to the surface.

👁️ Camera AI Checkpoint
  • • Evenly filled mold with a flat, leveled top surface
  • • Air bubbles steadily rising and popping at the surface during agitation
🛑 Watch Out For
  • • Adding excessive water, which weakens the concrete and leads to surface cracking
  • • Pouring too rapidly, causing trapped air voids around the logo bite and leaf details
⚠️ Safety Note: Wear an N95 dust mask and waterproof gloves to avoid breathing silica dust or suffering alkaline skin burns.
4

Demold and Sand the Concrete Logo

Allow the casting to cure undisturbed for 24 hours until fully hard and light gray. Unscrew the outer frame walls and carefully pry out the interior foam negatives using a flat scraper or knife. Sand all outer edges, the Apple bite contour, and the inner bottle chambers with 120-grit followed by 220-grit sandpaper for a smooth finish.

👁️ Camera AI Checkpoint
  • • Crisp concrete Apple logo that stands flat on its base
  • • Smooth, dust-free finish on all top edges and bottle recesses
🛑 Watch Out For
  • • Demolding prematurely before full cure, resulting in chipped edges
  • • Using coarse sandpaper aggressively, which exposes internal aggregate and ruins sharp edges
⚠️ Safety Note: Wear eye protection and a dust mask while sanding cured concrete to avoid dust inhalation.
5

Seat the Sealed Phone and Load Soda Chambers

Inspect your phone's waterproof case to verify complete seal integrity before inserting the dummy or protected test phone into the central display slot. Place unsealed bottles of Coca-Cola, Fanta, and Mountain Dew snugly into the designated concrete logo wells. Confirm the entire concrete base rests stable and level on an outdoor test table.

👁️ Camera AI Checkpoint
  • • Phone case firmly seated flush with the top face of the concrete logo
  • • Bottles standing perfectly upright without wobbling inside the cast wells
🛑 Watch Out For
  • • Failing to test the phone case seal prior to soda exposure
  • • Setting the heavy concrete base on an unstable or non-level surface
⚠️ Safety Note: Double-check that the phone enclosure is 100% watertight before proceeding to liquid experiments.
6

Deploy Mentos for Simultaneous Eruption

Roll four to five Mentos candies into paper tube sleeves for each soda bottle to allow quick, simultaneous loading. Drop the candies rapidly into the Coca-Cola, Fanta, and Mountain Dew openings simultaneously and immediately step back two paces. Observe the multicolored geyser streams erupting cleanly from the custom cement Apple housing without disturbing the seated phone.

👁️ Camera AI Checkpoint
  • • Immediate, high-pressure foam geysers spraying vertically from all bottles
  • • Concrete platform and phone case remaining structurally stable throughout the reaction
🛑 Watch Out For
  • • Dropping candies too slowly, causing the reaction to start before all Mentos enter the liquid
  • • Leaning over the bottle mouths during insertion, leading to direct facial spray
⚠️ Safety Note: Stand clear immediately after dropping candies to avoid soda spray in the eyes.

Credit: inspired by an original tutorial by Toys King — watch the original on YouTube.

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