3-Step Form using US-900 Electric
with UW-2 Wedge Bracket.

Concrete steps are generally poured either upside-down or straight up. Either way, our high frequency Model US-SOC or US-1600 is the most frequently used electric vibrator. The SVR-4000 can be used if air vibrators are desired. They are placed on form stiffeners on the inside transmitting the vibration to the form side. The same general rules for obtaining strong and smooth surfaces as for septic tanks apply.

Internal vibrators are used on many forms. The general disadvantages are that they tie up one man moving the vibrator around the form. They push air bubbles against the form side where they stick, leaving the surface pitted and unattractive to look at, sometimes leaving the customer believing the product is inferior. The external vibrators, by design, can be left running in the bracket, releasing the operator to do other work until the vibrator is turned off or moved. The vibration travels along the form side pushing the air bubbles away from it, up and out of the mix, leaving a void-free, smooth and attractive surface. For an especially smooth surface, sometimes a minute or so of vibration just before the concrete sets (after vibration) gives excellent results.