Soundown’s DC-3 Damping Compound is a viscoelastic, sprayable liquid sound damper. It has been found to be highly effective in reducing vibrational resonance conditions in structures such as passenger rail cars, elevator cabs, marine passenger and cargo vessels, stainless steel sinks
and other plumbing fixtures, sheet metal panels, floor housings, and a multitude of other applications. DC-3 dissipates structure-borne vibrational energy and reduces radiated air-borne noise.

DC-3 is resistant to water and a variety of solvents, acids and corrosive gasses. It is non-toxic, non-flammable, almost odorless and exhibits exceptional aging characteristics.

Water based and non-toxic, DC-3 offers an efficient and effective alternative to solvent-based sprayable damping products, as well as sheet applied damping materials. DC-3 can be sprayed or toweled directly from the drum without thinning. After application, DC-3 cleans up with water.

A typical setup to spray. DC-3 consists of a 30:1 airless pump, a reverse-a-clean airless gun with a tip size of 0.043", a ram and a surge tank.

DC-3 exhibits exceptional adhesion to a variety of materials when properly applied, and air-dries within 24 hours at room temperature. The drying time can be accelerated through oven drying using moderate temperatures. Its normal "tan" color may be varied for decorative purposes.


  • Sound Deadening Properties - OBERST BAR (SAE J-1637) METHOD - Composite Loss Factor of 0.036 @ 150 Hz, 25°C. Steel thickness 1.6 mm. Coating thickness 1.6 mm.
  • Cold adhesion - when DC-3 is applied to a 10" x 10" x 0.035" panel of primed cold rolled steel at the rate of 0.5 lbs.Isq. ft. (dry weight), shows no loss of adhesion when subjected to two 25" lb. impacts from a two inch diameter, 1% lb., steel ball at -20°F.
  • Fire Retardant - Passes ASTM E-162 "Surface Flammability of Materials Using a Radiant Panel Heat Energy Source."
  • Passes National Bureau of Standards and NFPA 258. Flaming and smoldering tests were conducted in an Aminco NBS Smoke Density Chamber, Cat. No. 4-5800.


Surface must be clean and free of oil and foreign matter. Adhesion is very good on stainless steel, bonderized steel, primed steel, wash-primed galvanized sheet metal, and wash-primed aluminum. Airless spray mastic type equipment is recommended for application.

Airless Spray - 0.043" to 0.051" spray tip, appropriate i.d. material hose, a Graco Bulldog@Pump 30:1 ratio or higher.


1/32" (32mils) wet film at room temperature dries hard in 3-4 hours.
9/64" (140 mils) wet film at room terperature dries hard in 24 hours.
Where faster drying time is required, use forced ventilation, heat or infrared light.


Product is ready for use as received. If conditions should require thinning, use water sparingly.


After use, equipment may be flushed with water.

  Viscosity Sparable Mastic Consistency
  Solids by Weight 55%
  Solids by Volume 40.8%
  Weight/Gallon 10.95
  Flash Point None
  VOC (EPA Method #24) 0 lbs.lgal. (water-based coating)
  Non-Bleeding Non-Asphaltic
  Odor After Drying None
  Chemical Resistance Resistant to dilute acids, alkali, grease, gasoline,
    and aliphatic oils.
  Latex Emulsion Protect From Freezing
DC-3 is not intended for direct outdoor weathering. The weathering resistance of DC-3 can be improved by painting.

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