I have a design for a (set of) planter(s) I'm trying to make, and to make the design I have in mind, I need an 18" long 3" OD leg with a bit of rebar in them. (let's say 100 of these bad boys in toto)

My initial thought was to cast it using PVC pipe and cut the pipe off, but pricing that off the top of my head has the cost of PVC to be about $60 in cost. I wanted to make the legs round, but would settle for square if that would be less cost prohibitive.

If I use PVC with endcaps, can I fabricate the legs in such a way that after "casting" I can neatly slide the legs out of the PVC pipes, thus allowing me to reuse the PVC repeatedly, or is there a better method for making over 100 18" 3" OD concrete (with rebar inserts) concrete columns than using PVC during the pour process?

If it matters, I was going to use quikrete crack-resistant concrete, but am totally open to ideas.

2 Answers 2


Yes, you could use 3" PVC schedule 40 pipe such as This one from The Home Depot. Cut it to length, then cut it lengthwise on one side and use duct tape to hold it together... This single cut will keep the round shape and when it has set, it will give you the ability to flex the pipe enough to have your cast come out. I would not use a PVC end-cap, but I would just make a duct tape one. Cutting ten foot length pipes will make you six molds per pipe @ ~$9 per pipe.. 100 casts in 8 batches for < $20.

  • Do you recommend prepping the inside surface of the PVC with a mold release? Or is PVC slippery/smooth enough that the concrete will come out of its own accord? Commented Jul 10, 2012 at 13:22
  • 1
    With the relief cut on one side, it should be smooth enough to come out on its own; however, if you find it is starting to have issues after a few batches, you could use something to lubricate the inside... You'll want to select a lubricant that won't cause your concrete to prematurely deteriorate.
    – ShoeMaker
    Commented Jul 10, 2012 at 17:00
  • We ended up not going forward with this idea at all, so it was a great idea, just never got implemented. Thanks again.
    – jcolebrand
    Commented May 18, 2014 at 20:15

Consider using a super-plasticizer, also called a water reducing agent. This makes the concrete highly flowable with very little water, so it maintains its strength.

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