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Spectrum™ Sludge Deadener

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Looking for a sound deadener to help create a bubble of comfort inside your vehicle? The first step is a liquid sound deadener like our Spectrum Sludge, the thickest noise and vibration paste on the market. Ordering Spectrum Sludge still gets you the Spectrum product, but we also include a bottle that contains our "Activator" formula. By stirring in the activator to Spectrum, the viscosity changes from comparable to chocolate syrup to more like peanut butter. All engineered to absorb vibration energy and reduce the transmission of structure borne noise in vehicles.


  • High heat, water based viscoelastic paste
  • Choose your thickness. Apply up to 2mm per layer
  • Excellent for hard to reach parts of your vehicle (undercarriage, wheel wells)
  • Comes with 2 containers – 1 gallon of Spectrum and 1 bottle of Sludge Activator
  • Temperature rated up to 400 F
  • Apply with a paint brush, putty knife, trowel, or gloved hand
  • Made in the USA


Product Usage Tips

  • Clean up with water within 30 minutes of application. Do not wait longer or Spectrum Sludge will dry.
  • If applying multiple layers of Spectrum Sludge, wait 30-60 minutes for the product to cure and change color from blue to black.
  • It must be above 50°F for the entire 24 hours cure period after applying Spectrum Sludge. Dry times increase with low temperatures and high humidity. If you expect longer than usual dry times, we recommend thinner layers (0.5mm instead of 1mm) to the same total thickness.
  • Spectrum Sludge is designed to adhere to metal. Do not apply to plastic or fiberglass without the proper primer. If applying to a high gloss wax coat, you must sand down and apply a primer.
  • Do not freeze Spectrum Sludge! If it does freeze, do not mix, shake, or move until it has completely thawed.
  • Wait 24-36 hours (depending on humidity) before putting upholstery back in the vehicle. Wait 7 to 10 days before painting or applying a bed liner.
  • As Spectrum Sludge cures, its deadening properties will continue to increase. Vibration damping doubles from 4 hours --> 48 hours, and continues improving for 7 days.
  • Spectrum Sludge is not a bed liner. Even after it has cured, it can be damaged by heavy impact.
  • Shelf life of 1 year when stored at room temperature


Second Skin Spectrum Sludge car application surfaces and square footage


Application Instructions

  1. After upholstery or carpet is out, remove loose debris, rust, dirt, and waxy oils to insure a solid contact surface. Most new cars will not need much prep work, while some older vehicles should be treated with denatured alcohol.
  2. Spectrum Sludge is a two-part system. The first part is a bucket of our original vibration coating, Spectrum. The second part is a 6 oz bottle of Sludge activator – the catalyst that turns Spectrum into the sludge-like paste. The more activator you add, the thicker Spectrum gets.
  3. Slowly mix one 6 oz bottle of Sludge activator for each gallon of Spectrum while stirring rapidly. A paddle mixing drill bit will work best. Do not mix the entire bottle of Sludge activator all at once. The entire process should take about 90 seconds while using an electric paddle. If mixing by hand, the process should take about 5 minutes.
  4. Once thoroughly mixed to a consistent viscosity, apply Spectrum Sludge to the metal surface. It must be applied at least 1mm thick to properly deaden the metal. We generally recommend a 2mm thick application. At 1mm thick, a gallon will cover about 40 square feet.
  5. Do not apply more than 2mm in one layer. Spectrum Sludge will skin over and turn from blue to black over 30 to 60 minutes depending on the temperature and humidity. Additional layers can be applied after it has changed color to black.
  6. Spectrum is easy to clean up with water if done within 30 minutes of applying the product.
  7. Allow 24-36 hours before another product or upholstery is installed. Spectrum may be painted or covered with a bedliner after 10 days.


Spectrum Install Guide


Second Skin Spectrum Sludge product specs


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Product Category:
Material Type:
Vibration Damping