Instructables
Picture of DIY CONCRETE:: Umbrella Base
Umbrella_Instructable_01.jpg


This Instructable will show you how to make a concrete umbrella base from an IKEA lamp shade using basic tools and materials. The lamp shade is relatively cheap and makes an attractive concrete mold that can be re-used for dozens of castings. The size of your umbrella will determine the diameter of the pipe that gets cast into the concrete, and also the overall size of the base. For larger umbrellas or gusty spaces, you'll want a larger umbrella base that weighs about 100 pounds. The smaller lamp shade makes a base that weighs about 60 pounds.

There are four steps in this Instructable - Assembling the Form, Casting Concrete, De-molding, and Finishing.

Materials and Supplies:
  • IKEA Melodi Lamp Shade or similar plastic container
  • 3/4" Plywood (approximately 16" x 16") for Base Board
  • 3/4" Plywood for Bracing
  • 2" Galvanized Pipe with Floor Flange OR PVC pipe (Actual size is determined by your umbrella pole.)
  • 1" x 3/4" Foam Strip 50" long, covered in clear packing tape
  • 100% Silicone Caulk
  • Modeling Clay
Tools:
  • 2-1/2" Hole Saw and Drill
  • Screw Gun
  • Pre-Drill and Countersink Bit
  • 1-1/4" Drywall Screws
  • Hack Saw or Angle Grinder
  • Concrete Polisher (optional)
Concrete Mixing:
 
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johnnymerg3 months ago
Is a release agent needed, or is the plastic slick enough to not need one?

In this case the plastic is very smooth on the inside and you won't need a release on the first casting. It really helps to leave a 1" gap (don't fill the form to the top), so you can flip the piece over and use the weight of the concrete to help it drop out. If the piece is still stuck, you can blow compressed air down between the plastic and the concrete to help break the seal.

If the form has been used once before, it needs to be cleaned very thoroughly. Small scratches or concrete residue inside the form will make the concrete a lot more difficult to remove. I'd recommend a very light coat of mold release after the first casting.

useraaaaa1 year ago
like!

i wana make something like
http://mylongwalk.com/Common/Benches%20in%20Britain/Concrete%20sided.jpg

that doesnt seem to difficult. just a matter of making the the proper form, that you even could form out of polyurethane