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.
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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
- • Wear safety goggles, an N95 dust mask, and heavy-duty nitrile gloves when mixing dry concrete.
- • Ensure all live smartphones are secured in an IP68-rated hard case before loading sodas.
- • Conduct the soda eruption phase strictly outdoors on a level, clear surface away from power outlets.
📋 Step-by-Step Guide (6 Steps)
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.
- • Smooth vertical foam edges resembling the Apple logo
- • Custom foam pockets that match the diameter of the soda bottles and phone case
- • 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
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.
- • Perimeter walls completely sealed at the base with no light visible through gaps
- • All interior foam coated with a light sheen of release agent
- • 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
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.
- • Evenly filled mold with a flat, leveled top surface
- • Air bubbles steadily rising and popping at the surface during agitation
- • 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
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.
- • Crisp concrete Apple logo that stands flat on its base
- • Smooth, dust-free finish on all top edges and bottle recesses
- • Demolding prematurely before full cure, resulting in chipped edges
- • Using coarse sandpaper aggressively, which exposes internal aggregate and ruins sharp edges
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.
- • Phone case firmly seated flush with the top face of the concrete logo
- • Bottles standing perfectly upright without wobbling inside the cast wells
- • Failing to test the phone case seal prior to soda exposure
- • Setting the heavy concrete base on an unstable or non-level surface
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.
- • Immediate, high-pressure foam geysers spraying vertically from all bottles
- • Concrete platform and phone case remaining structurally stable throughout the reaction
- • 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
Credit: inspired by an original tutorial by Toys King — watch the original on YouTube.
Don’t have everything?
- No XPS foam board? High-density EVA foam sheets or stacked corrugated cardboard wrapped in tape
- No Mold release spray? Canola cooking spray or a thin film of petroleum jelly
- No Melamine board? Smooth plastic cutting board or laminated shelf piece