![Matching the size of the vibrator to the job and limiting the insertion spacing to one and a half times the radius of influence will minimize honeycombing and other form surface blemishes.](https://img.forconstructionpros.com/files/base/acbm/fcp/image/2012/06/cc-forming-figure-2_10726182.png?auto=format%2Ccompress&fit=crop&h=288&q=70&w=512)
Matching the size of the vibrator to the job and limiting the insertion spacing to one and a half times the radius of influence will minimize honeycombing and other form surface blemishes.
- Deposit concrete with a maximum lift thickness of about 20-inches. Make lifts level as possible and do not use the vibrator to move concrete horizontally.
- Plunge the vibrator vertically into the concrete. Use a uniform spacing not to exceed about one and a half times the radius of influence over the entire placement area.
- Let the vibrator sink by means of its own weight to the bottom of the lift and penetrate the previous lift about 6 inches.
- Manipulate the vibrator with an up-and-down motion for 5 to15 seconds to knit the two layers together. Do not worry about over-vibrating the concrete; most concrete is under-vibrated.
- Withdraw the vibrator gradually with a series of up-and-down motions so air bubbles are worked upward in front of the vibrator.
- Rapidly extract the vibrator from the concrete when the head becomes partially exposed. If the vibrator hole does not close, partially and quickly reinsert the vibrator a short distance away from the hole.