DIY Monogrammed Concrete Coasters
Materials and Tools
Stir Stick
Ink Pen
Scissors
Foam Brush
#240 Grit Sand Paper
Thin Adhesive-backed Cork
Small Wooden Letters
Hot Glue Gun
Glue Sticks
Coaster Molds
Gloves
Bucket
Concrete Form Release – For easy release from the mold
Concrete Overlay
Acrylic Water-based Concrete Sealer
Step 1: Create Your Mold
Figure out what you want on your coasters. You can add anything to the mold as long as it’s no thicker than the mold itself. If using initials, be sure to invert your letters before applying them to your mold.
Using your hot glue gun, add a dab of glue each piece to the coaster mold. If you mess up the placement, carefully pull the pieces off the mold. Our letters were quite thin so a few broke when we pulled them off. Be sure you have a few extra pieces lying around just in case.
Remove any excess glue from the edges so your concrete coasters don’t show that once you cast them.
Step 2: Spray Your Mold with Mold Release
We used Countertop Mold Release for easy mold removal. Spray enough mold release to saturate the wooden pieces. There may seem like a lot in the mold but that’s ok. It’s better to have too much than too little.
Step 3: Mix Your Concrete
Wear gloves. Mix your concrete with water. We added water and mixed our concrete until we achieved a pancake- batter like consistency. Make sure you mix your concrete thoroughly. Any dry lumps can create weak spots and voids in your concrete.
Step 4: Pour Your Concrete and Let Your Coasters Cure
Pour your concrete mix in your prepared mold. Smooth out any rough edges or peaks with a stir stick or your finger (it doesn’t have to be perfect). Tap the mold to get most of the air pockets out of the mix.
•  Concrete Overlay can be poured pretty thin and still hold together well.
• Ready mix concrete from home improvement stores will need to completely fill the mold so they don’t crack when removed from the mold.
• This can make the finished product really heavy (another reason why we used Concrete Overlay).
*Note: If your location isn’t level, use something to put under the coaster to keep it as level as possible. It’ll be easier to finish the coasters if they’re level.
*Additional Note: pour your concrete wherever you can allow the mold to sit for a few days. If the concrete is moved prior to 48-72 hours, it could crack.
Concrete Overlay needs 48-72 hours to cure. Ready mix concrete from home improvement stores needs at least a week to cure.
Step 5: Remove the Coaster from the Mold
After your concrete has cured, carefully tip the mold over and remove your coaster.
Step 6: Sand Rough Edges
Gently sand any rough concrete edges with a #240 grit sand paper.
Step 7: Seal Your Concrete Coaster
Seal your coaster with a concrete sealer. We used Acrylic Water-based Sealer for its durability and low odor.
Apply the sealer in thin, even coats with a foam brush. Be sure to coat the edges as well. If any bubbles occur, gently work them out with the foam brush.
Allow the coaster to dry completely (6 hours max) before applying your cork backing.
