There are four steps in this Instructable - Preparing the Lid, Mixing and Pouring Concrete, Grinding and De-molding, Sealing and Finishing.
- Plastic Tupperware Lids
- CHENG Countertop Pro-Formula Mix
- Sakrete 5000+ Concrete or equivalent
- Decorative Aggregate - optional (semi-precious minerals, crushed glass, etc.)
- Particle Mask
- Rubber Gloves
Step 1: Preparing the Lid
- Coaster Size = 4+ inch
- Trivet Size = 6+ inch
- Flexible Plastic
- Plastic that is durable enough to be re-used
- At least 1/4 inch thick
- Not threaded inside (so concrete can be released from the lid without having to break it off)
- No logos
- Free / Cheap
- Paper / Cardboard
- Thinner than 1/4 inch
- Undercuts / Threads / Deep Logos
- Thin plastic is OK for one casting, but can't be reused easily.
- Clean the lids with soapy water using something that won't scratch, like a 100% cotton cloth.
- Use a light mist of spray adhesive in the lid if you want to include decorative aggregate, crushed glass, or any kind of inlays.
- Use crushed glass and decorative aggregate that complements the color of the concrete.
- Rubber stamps can be fixed to the form with spray adhesive and removed after the concrete has cured, leaving the rubber stamp pattern as a relief in the surface.