Balloon Density Apparatus

Model: HM-66
Price: $708.00

Balloon Density Apparatus determines the in-situ density and unit weight of the soil when testing compacted earth fills. The Balloon Density Apparatus is a water-filled, calibrated vessel fitted with a hand-operated pump to pressurize the chamber. A thin, flexible membrane (rubber balloon) on the bottom displaces under pressure to fill a void.

Using the base plate as a template, a hole is dug in the surface, and the excavated soil is retained as a moisture specimen. To determine the volume of the hole, the density tester is mounted on the plate, the balloon is pumped into the hole, and fluid displacement from the vessel is noted. In-place density is computed by dividing the weight of the retained soil by the measured volume of the hole. A portion of the retained specimen is used to determine moisture content. Water volume is read from the double-graduated scale on the high-strength clear plastic cylinder. The selection of the Balloon Density Tester is determined by the top-size soil particles.

HM-66 has 1/20ft³ (1.6L) capacity and is used for soils with 1/2in (13mm) maximum particle size.

Each apparatus consists of a graduated cylinder (0.00025ft³ and 7cm³ graduations), base plate, pressure/vacuum pump assembly with quick-coupler, twelve balloons, and an integral gauge for controlling pressure during calibration and testing. The MA-26X Aqua-Check Moisture Tester for moisture determinations and HMA-8 In-Place Density Accessory Kit are recommended optional accessories.

Note: this method is not suitable for very soft, easily deformed soils or in a hole that will not maintain a constant volume.


  • A durable, clear plastic cylinder makes double graduations easy to read
  • Comes with all the components needed to measure the in-place density of soil
  • HM-66 model is used for soils with a particle size up to 1/2in (13mm)

Included Items:

  • Balloon Density Apparatus
  • Double-graduated cylinder
  • Baseplate
  • Pressure/vacuum pump assembly with quick-coupler
  • Pressure gauge
  • (12) Rubber balloons


  • HMA-5 Voluvessel Balloons are used to pump in the hole to fill the void, sold in a package of twelve
  • HMA-8 In-Place Density Accessory Kit includes sample bags, pocket thermometer, bristle brush, chisel, stainless steel spoon, and rubber mallet, all necessary for field density tests for Balloon Density or Sand Cone Density
  • MA-26X Aqua-Check Moisture Tester allows for fast, accurate testing of sand, soil, or other aggregates

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Estimated Shipping Weight

HM-66: 12.0lb (5.44kg)

HM-67: 13.0lb (5.90kg)

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Estimated Shipping Weight

HM-66: 12.0lb (5.44kg)

HM-67: 13.0lb (5.90kg)

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