3. Supplies + Tools
I used the classic Lego bricks to make the mold. I raided my parent’s attic to retrieve my childhood stash and purchased a few new sets. Purchasing all new bricks for this project might be a bit expensive, so I’m working on a post showing how the nightstand could be cast in sections to reduce the amount of Lego bricks needed.
3/4” Melamine Board
Melamine board is particle board with a smooth laminate surface. It’s a great product for making a concrete form work. I bought a 4’ by 4’ sheet and had four 2 1/2” strips cut at Home Depot.
Quikrete Countertop Mix
I prefer the Commercial Grade Quikrete Countertop Mix for these type of projects but Quikrete 5000 will work just fine as well.
Hot Glue Gun
I used a hot glue gun to glue the Legos to the board. Don’t worry – the glue will peel off later.
4. STEP 1: Layout the Mold
Layout the design and build the mold 3 bricks high. Place temporary spacers to get the inside and the outside rings in the right position.
5. STEP 2: Glue Down the Lego Bricks
Use the hot glue gun to glue the Legos to the melamine board.
6. STEP 3: Finish Building the Mold + Mix + Pour the Concrete
Build the mold up brick-by-brick. When you get to the top, place some support braces to keep the walls from bending out under the weight of the concrete. Mix the concrete and spoon it into the form. After you have put in about 3 inches of concrete, use a stick to push the concrete into the corners and vibrate the air bubbles out of the concrete. Repeat this process until the mold is full.
7. STEP 4: Remove the Mold
Let the concrete cure for at least 20 hours before removing the mold. Removing the Lego bricks can be a bit time-consuming. Remove the upper layers and then cut the glue with a knife. Flip the block over and start removing the bottom bricks. You can use long nose pliers to remove the bricks from the bottom, but be careful not to scratch or bend the plastic bricks.
8. STEP 5: Add a Drawer + Legs + Clean the Lego Bricks
The concrete part is quite heavy, so you might want to glue the lego bricks together if you do use them. Most of the dried concrete flakes off the Lego bricks. Some small pieces can be scraped or brushed off with a toothbrush. Only use cold water and mild, non-abrasive soaps to clean the bricks. If you have a mesh bag for laundering delicates, you can place the bricks in the bag and wash it in a washing machine with the water temperature set to cold. Do not use hot water or you will warp the bricks.
9. For complete, step-by-step instructions, click here.
12. For complete, step-by-step instructions, click here.
For complete, step-by-step instructions, click here.