Skill Level:
- Beginner - Intermediate
- 3/4" Melamine coated particle board (13"x13")
- 1-1/4" Drywall Screws
- Blue Insulating Foam / Styrofoam 2" thick
- Spray Adhesive (3M 77)
- Clear Packing Tape
- CHENG Outdoor Pro-Formula Concrete Admixture
- Sakrete 5000+ Concrete Mix
- 8" Concrete Form Tube (13" length)
- Hand Saw
- Jig Saw
- Screw Gun + Pre-drill / Countersink bit
- Drill + 7/16" Drill Bit
- Caulking Gun + 100% Silicone
- Sanding Block + Sandpaper (60,100,220 grit)
- File / Rasp
- Bucket / Wheel Barrow
- Shovel / Trowel
- Particle Mask
- Rubber Gloves
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Signing UpStep 1: Construct Lid Form
- Take one 5 gallon bucket and saw the rim off 2-3" below the top edge. This is done easily with a handsaw. How much you cut will determine the thickness of the lid.
- Put the top of the bucket on the base board (rim facing up) and surround it with the support blocks (3-1/2" x 4"). Pre-drill and screw supports in place through the base board using 1-1/2" screws.
- Caulk the inside edge to make the form water tight. Allow the silicone to fully cure and then remove the excess.
- Cut a ring out of 3/4" melamine coated particle board with a jig saw. The ring should fit tightly and needs to be close in size to the inside diameter of the rim. Slide the ring down into the bucket section until it's flush with the rim.
- Install four small wood blocks over the top of the rim to hold it down during casting.
- Clean out the form and it's ready to pour.










































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One improvement I'd love to see, I had to read the whole thing to figure out where you were going with each step. A nice overview drawing or explanation would be super helpful. Something along the lines of, you'll cast a lid with one bucket using a wooden backing, and the body will be cast with a second bucket and a sonotube inside.
You can't cover all the details, but the importance of tamping or vibrating, mixing the concrete completely, and a little more about how to grind the concrete (that looked so darn cool in your later steps) would be helpful.
This is an awesome cool idea.
Here's a picture of how to use a smaller bucket as a knockout. I'll take some pictures of the planter I made using this method and post them up.
I'm pleasantly surprised to find it a generic set of instructions - thank you for doing it right and not abusing instructables with advertising.
One thing you did not mention is to tamp down the concrete to eliminate voids. It appears you did that, though. When casting concrete countertops some people place the form on a vibrating table and fill it with concrete, then vibrate for a few minutes.
I think I may try this.
I agree with danzo, tho, for making it easier.