The job of the vibratory feeder bowl is to sort and line-up igniter bases for the next step in the manufacturing process. Two inch aluminum discs are dropped into the bowl in bulk. It then vibrates the parts, getting them move up the ramp in single file to be picked up by a conveyer belt. A pair of large motors are attached to the bottom of the bowl to create the fast movements needed to get the parts moving up the ramp.   

 
The easiest way to apply Noisekiller liquid is to spray it. However, because this was a semi 'clean-room', we weren't able to spray. NoiseKiller liquid is just as easily applied with a brush or a roller like regular paint. The feeder bowl's thickest metal was on the bottom. Here we applied four coats to a total thickness of approximately 0.060". The remaining areas were given three coats totaling 0.045" thick. Total time for this job was approximately four hours including prep work and waiting about 25 minutes in between coats.
 

Once the last coat was applied, final cleanup was done with a sponge and water. No solvents or chemicals are needed to remove unwanted Noise Killer because Noise Killer liquid is water based. The job was dry to the touch in less than 30 minutes, but it takes a minimum of 24 hours for the Noisekiller liquid to begin damping effectively. This is because it needs to cure, evaporating the water out of it as it goes. When fully cured, Noisekiller liquid is waterproof as well as gas and oil resistant. This seals the surface from contaminants and greatly reduces any chances for rusting.
 

without NoiseKiller

with NoiseKiller

   
Here's an octave band response of the feeder bowl before and after (bottom line) treatment with NoiseKiller. It's most effective where your ear is most sensitive.

The results speak for themselves. Before NoiseKiller was applied to the feeder bowl, the average noise level in the room was 101dBA. Two days after the NoiseKiller application, the noise level was reduced to 89dBA, a reduction of 12dBA. Since sound is logarithmic and not linear, this represents a sound reduction of 16 times less sound.

A metal enclosure was constructed and lined with airborne sound absorbing material to further lower the noise level to the OSHA limit of 85dBA.
Hearing protection used to be a requirement in this room. Now an employee can enter at any time without restriction.