I installed an aluminum fence using 80 pound yellow back Quikrete and after about 12 hours some posts were loose. Now after closer to 18 hours they seem better. How long does it take before the fence posts are totally secure? I did not see specifics for this on the bag.

We mixed the concrete per the instructions and videos I saw. It was like thick lumpy oatmeal and formable and certainly not liquid. We used a tamping bar but I was not sure how much or little to tamp it down with either end of the bar. What is the best way to work the concrete once it is in the hole?

  • OK, I'll be the first to say it, you should set the posts, then leave them alone for 24 hours. Wiggling them is like anti-tamping. May 23, 2021 at 15:37
  • I agree, that was a damaging blunder, and may not be recoverable. Like moving a solder joint before it's hardened, or manipulating epoxy before it's cured, or handling a painted part before it's dried. Don't let curiosity drive you to do stuff like that. May 25, 2021 at 7:00

1 Answer 1


Most of the concrete I've used wants 24 hours to cure. There are quick setting bags out there where you don't mix anything, you just pour the dry concrete in the hole and add water and they can set in 4 to 5 hours. If you mix it and then tamp it in, 24 hours is pretty standard but quit testing the poles, you'll just loosen them up. You want to tamp it in every 6". I've just used a piece of 2x4. Don't worry about over tamping.... have at it.

  • Thanks, what do you mean tamp every 6 inches? Do you mean tamp it down with the pointed end or the round end of the tamping bar?Thanks again. May 23, 2021 at 11:57
  • @ScottLittig You would dig with the pointed end and tamp with the round end. Tamp every 6" of poured concrete.
    – JACK
    May 23, 2021 at 12:05

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