I made reusable silicone molds out of Mold Star 30 from Smooth On so that I could make a bunch of these geometric concrete planters. I made the originals out of 2x6s from Home Depot. This project took about 4 hours to make and cost around $70.

SUPPLIES:

Quikrete Countertop Mix in White
Home Depot
I used Quikrete countertop mix in white to make the white concrete planters.


¾” Melamine
Home Depot
I used ¾” melamine to make the forms.


Mold Star 30
Smooth On

TOOLS:

RYOBI Glue Gun
Available at Home Depot












RYOBI Belt Sander
Available at Home Depot














RYOBI Compound Miter Saw
Available at Home Depot









RYOBI 18 Volt Cordless Drill
Available at Home Depot












RYOBI Orbital Sander
Available at Home Depot

INSTRUCTIONS:

STEP 1: Prepare the wood.
I made the originals out of 2x6s that I bought from Home Depot. 2x6s are rough construction lumber and have rounded edges so I ran them through the planer. If you don’t have a planer you could trim the edges with a circular saw or table saw. I then cut the pieces to length. You can make these planters whatever size you want and measurements are not as important as just making them the way you want them to look.





STEP 2: Drill big holes.
I used a hole saw to drill large diameter holes in the 2x6s. I used a 3" diameter hole saw.





STEP 3: Glue the pieces together.
I used wood glue to glue the pieces of 2x6s together and clamped them tightly.





STEP 4: Shape and sand.
I used my belt sander with 60 grit and 80 grit belts to shape these blocks of wood. I just kept sanding down corners until I liked the way they looked. I used a drum sander on my drill to smooth down the rough holes that the hole saw cut.







STEP 5: Seal.
I coated the planters with 3 coats of miniwax polycrylic using a foam brush.



STEP 6: Wax the holes.
I didn't want the silicone to stick to the insides so I melted soy candle wax and coated the inside holes. Once the wax had solidified I used a blade to scrape away the excess.





STEP 7: Glue a mold around the planters.
I hot glued pieces of melamine around the planters and glued the planters down to t a bottom piece of melamine. I sealed all the outside edges with hot glue. I wanted the wall of the silicone molds to be about 3/8" thick at a minimum.





STEP 8: Mix and pour the Mold Star 30.
I mixed and poured the Mold Star 30 over the planters.



STEP 9: Remove the melamine.
I used a putty knife to break down the melamine molds and pry the wood planters off of the bottom piece of melamine.







STEP 10: Mix and pour concrete.
I mixed Quikrete countertop mix in white and poured it into the molds.







STEP 11: Remove.
After letting the concrete cure for 2 days I removed them and rinsed them off before adding plants. The molds are reusable and I have made 6 sets of planters out of my molds so far. The wood originals were not injured and look great!















Good luck making your own DIY plywood shelves and please email or tweet photos to @benuyeda or [email protected] If you want to see what we're working on next, follow us on Instagram: @benjaminuyeda and @ijessup. Also check out our book for additional projects, DIY tips and guides.

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