Sound Damping

Heavy mineral-loaded sound damping coating reduces noise energy within aluminum and steel by as much as 10-12 decibels in the low, 150-1000 Hz frequency range.

That's a reduction of up to half the sound energy that can be reduced over and above noise reduction from use of sound barrier and absorptive soft mass materials. Sound damping coating replaces traditional damping tiles at a significantly lower application cost, longer service life and comparable performance.

Sound damping coating yields a 10-12 dB reduction in addition to the sound reduction provided by sound barrier (dense mass layer sandwiched between two soft mass layers) and absorbent soft mass. Performance testing are based on use of a ratio of 25% coating weight to plate weight with application on 70% of surface area between stiffeners. The chart below shows thicknesses (wet film and dry film thicknesses for various plate weights).

Best performance application surfaces for sound damping would be as follows with primary damping application areas:

  • Machinery/engine space overheads
  • Machinery/engine space forward bulkhead
  • Machinery/engine space sidewalls 
  • If engine stringers are solid mounted - application on both sides. 
  • Engine air intake duct surfaces 
  • Crew quarters/tank & gyro space bulkhead

 

Secondary damping application areas:

  • Forward chine where waveslap produces noise
  • Machinery/engine space aft bulkhead 
  • Fuel tank forward vertical face & tops (where exposed)
  • Lower sections of sidewalls on house. Basically a 1' band running along the base of the sidewall on the flat plate.

 

Sound Damping Coating Thickness Chart Based on 25% Coating to Plate Weight Ratio on 70% of Surface Area Between Stiffeners:

Aluminun Plate

Plate Thickness in inches

Plate Weight in Lbs.

Coating Weight @25% of plate weight in lbs.

Net weight per SF @70% surface coverage - lbs.

Mil Thickness indicated @0.0115 lbs/mil

Wet Film Thickness based on 70% solids content

Application coats @ up to 35 mils WFT following a 15-20 mil "tack" coat

Bottom - 5/16"

0.31

4.56

1.14

0.80

99

142

4

Engine Bulkhead - 1/4"

0.25

3.64

0.91

0.64

79

113

3

Engine Stringers - 3/4"

0.75

10.9

2.725

1.91

237

339

4 on each side

Deck Head - 3/16"

0.19

2.6

0.65

0.46

57

81

2

 

A coating weight to plate weight ratio of 25% on yields optimal performance according to extensive testing. On engine stringers, apply coating on both sides of the plate to reduce the overall thickness of the application. The mass will be the same.