How to make concrete fence posts and mail box supports

by Pete Scaffidi
(Medford, New Jersey)

Q. What is the best way to make multiple concrete fence posts 4" sq without having to make a lot of forms? What mix is best to use?

A. Depending on the length of your concrete fence posts you could use a sheet of plywood (for 4' length) or 2 sheets if longer and either rip down a 2x6 to 4" or use a 2x4 and add a strip of 1/2" plywood to one side to make it 4". Screw the 2x4 to one end of the plywood, measure over 4" and screw another 2x4 parallel to the first, repeat this until you reach the other end of the plywood. You should be able to make 17 - 4'x 4"x4" concrete fence posts per 4' x 8' sheet of plywood.

You can use Quikcrete 5000 with air-entrainment for a bag mix. Mix per instructions, Shovel the mix into the form, tap with a hammer to consolidate, and trowel off the exposed edge of the fence post. Drop in a 1/2" piece of rebar for reinforcement in each fence post before troweling. Cover with a sheet of plastic to help cure the concrete slowly, and let sit for 3 or 4 days before stripping the forms.