How to Make a Rad Concrete Coffee Table With Live Edge Cherry Slab
by Woodbrew in Workshop > Woodworking
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How to Make a Rad Concrete Coffee Table With Live Edge Cherry Slab
This week we made a coffee table made out of concrete and a cherry slab from downtown Birmingham, AL. This project turned out soo cool and Alex from Mr. Build It did an awesome job with the legs! Praise the Lord that the concrete didn't break on us and everything worked out!
Alex's Channel: https://www.youtube.com/channel/UCziz6FiCnkyQ810X... Alex's Instagram: https://www.youtube.com/channel/UCziz6FiCnkyQ810X...
(affiliate links below)
Orbital Sander: https://amzn.to/2vYIeX1
Belt Sander: https://amzn.to/2rawa05
Best sand paper ever: https://amzn.to/2HC1Ohn
Electric Handplane: https://amzn.to/2vYKYDP
Chisels: https://amzn.to/2HBzJ9W
Prepare the Live Edge Slab for the Mold
Its important that the top side of your slab is somewhat flat. It doesn't need to be perfect, but the closer to flat it is the better the end result will be.
We are starting with a slab that has cupped and is not even close to being flat...
You have a few options to get the slab flat:
- Use a Router and a jig to flatten the top
- Use a hand plane (Powered or manual)
- Use a belt sander and a lot of time
- Use a large piece of machinery to flatten the slab
- Or research other methods of flattening
We chose to use a router without a jig to remove the high spot in the middle and then a powered hand plane for the rest.
To finish the slab off we use 120 grit sand paper and a chisel to remove the bark.
(affiliate links)
Orbital Sander: https://amzn.to/2vYIeX1
Belt Sander: https://amzn.to/2rawa05
Best sand paper ever: https://amzn.to/2HC1Ohn
Electric Handplane: https://amzn.to/2vYKYDP
Chisels: https://amzn.to/2HBzJ9W
Making the Mold
We are using a piece of melamine particle board to give us a smooth top surface. We were lucky and able to use a precut 2ft x 4ft panel.
Our slab wasn't perfectly flat so we decided to use some caulk to seal up the edges. Place the slab with the top facing down onto the piece of melamine and let the caulk dry. We used some scrap 3/4" plywood to make sides for the mold. Our sides were 3 3/4" tall giving us a 3" thick table when you subtract the bottom of the mold. Just screw the side pieces in and you really don't have to caulk them.
Concrete doesn't stick well to wood so we need to make sure they stay together. Screw a bunch of screws into the wood slab and make sure they don't stick above your side pieces. These screws will hold the concrete to the wood and will give strength to the concrete where it over hangs. We also used some wire between screws to bridge long areas.
The Pour
We used two 80lb bags of 5000 psi high strength concrete for this project. You can find it right next to the standard bags at any hardware store. This concrete is stronger and leaves a better surface in our experience. The brand of concrete is irrelevant.
Mix your concrete in small batches to insure your are mixing it thoroughly. If you mix to much at once you risk pouring unmixed concrete into the mold and causing problems. We usually do a slightly wetter first pour and pretty dry pours after that.
Pour the concrete into the mold and push it into crevasses with a trowel. Use a long board to level the surface out by moving it across the top. This gets messy so be prepared.
Let this cure for at least 72 hrs
Finish the Table
Carefully remove the table from the mold. You may find it still a little damp... if so wait a few more days for it to fully cure.
Sand everything with 120 grit sandpaper and apply a clear coat. We decided to spray on a water based polyurethane, but pretty much anything will work.
Add legs to the table and your done!! We used some legs made by our friend Alex... check those out here:
https://youtu.be/aUYTBBvaHx0