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Spectrum Sludge - 1 Gallon * MADE IN USA*

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Product Description

Spectrum Sludge - 1 Gallon


Spectrum Sludge™ is the thickest noise and vibration paste of its kind specifically formulated by Second Skin with Mica, Talc, Calcium Carbonate, and crushed rubber. Sludge comes with a base gallon of Spectrum and  a separate container of  a thickening  additive. By increasing the amount of the additive mixed into Spectrum, the viscosity will change from a chocolate syrup thickness to a peanut butter thickness. Sludge may then be installed with a gloved hand or trowel. 

Spectrum Sludge is a high temp water based viscoelastic polymer damper designed to be installed on the interior or exterior of prepared sheet metal, fiberglass, carbon fiber or aluminum. Stopping the vibrations is like holding a noisy wind chime or bell with your hand. Once the vibrations stop the noise stops. Spectrum Sludge kills vibrations in a similar way - It stops the structure from vibrating, thus, reducing noise.

Each gallon of Spectrum will cover 10 sq ft at the recommended 3 coats for a total thickness of 3mm. Each coat should be applied at 1mm thickness 30-60 minutes apart. Once the final coat has been installed, allow 24 hours before the next layer of product or upholstery is installed. Spectrum may be painted or covered with a bed liner after 30 days.  

The next step is to reduce air borne noise by installing a noise barrier MLV (Mass Loaded Vinyl) Luxury Liner Pro on top of Spectrum

 A water based primer must be installed to plastic, aluminum or fiberglass prior to installing Spectrum.

Application surface should be dry and free from rust, oil, dirt and debris. Denatured alcohol works well to pre-clean leaving no film. For high rust climates and previously rusted metal install POR 15 first. 

*Spectrum Sludge cleans up with water*

 * 400 degrees heat rated*

  *Do not freeze* If product freezes do not mix, shake, or move until completely thawed. 

*Do not apply product in temperatures below 50 degrees Fahrenheit.

*Spectrum and Spectrum Sludge are not bed-liners and may be damaged by foot traffic*

Spectrum has a shelf-life of six months, provided it's stored at room temperature. 

Noise Reduction Uses

  • Under Carriage
  • Wheel Wells
  • Truck Bed (Before a bed liner)
  • Door Skins - Outer Skin & Inner Door Frame.
  • Floor - From the front firewall to rear deck.
  • Firewall - Cabin side or engine side (450 degree heat rating). 
  • Van/Semi/SUV Panels 
  • Pillars - A, B, and C pillars. 
  • ATV's
  • Trunk
  • Generators (Must be 2" away from  heat sources)
  • Computer towers
  • Metal Screen Doors 
  • Coin Counting Machines 
  • Warehouse/Hospital Carts or Tables 
  • H VAC Ducts
  • Elevator Shafts 


Weight per wet gallon = 12.5 lbs.

Weight per cured gallon = 11.0 lbs

Coverage: 1 gallon = 40 sq ft @ 1mm thickness

Coverage: 1 gallon = 10 sqft @ 3 mm thickness (2-3 Coats) Recommended

Appearance & Physical State        Pigmented liquid/paste

Color                                             Wet Blue/Black once cured

Odor                                              Very Mild Solvent/None when cured

Viscosity                                        4000 centipoise

Specific Gravity (water = 1)         1.45

Vapor Density (air = 1)                 >1

Boiling Point                                  >400 Degrees Fahrenheit

Solubility in Water                         Soluble  

Percent Volatile                             25

Layer Thickness                             1 mm or 0.040"

Thermal Insulation

Spectrum Sludge contains Mica, Talc, Calcium Carbonate, and crushed rubber. All of these ingredients help stop thermal transfer.


 What is the difference between Spectrum & Sludge?

Spectrum and Sludge are nearly identical products. The only difference is the viscosity: Spectrum has the consistency of heavy chocolate syrup and is easy to spray, brush or roll on. Sludge has the consistency of peanut butter and is too thick to spray, but can easily be applied with a putty knife, trowel or gloved hand. 

How long does Spectrum take to cure?

A 30 full days to fully cure but will be dry to the touch in 30-60 minutes depending on the ambient temperature and humidity.

When can I put my upholstery back in place?

24 hours is recommended. 

What is better, Spectrum or Damplifier?

Both products are designed to do the same basic function: Reduce noise through the reduction of vibrations. Both have their place, and both excel at specific frequency ranges. This is why we suggest using a combination of damping mats and coatings. For example: 
Install Damplifier Pro on interior sheet metal then use Spectrum for the hard to reach locations. Or, install Spectrum to the underside of the cars floor pan and wheel wells. This will sandwich the sheet metal between Damplifier Pro & Spectrum.

Suggested Thickness:

 Minimum = 40 mils (1mm)

Recommended thickness = 118 mils (3mm)
Maximum = 196 mils (5mm)







Product Videos

Making Second Skin Spectrum Sludge Sound Deadener 05:01

ANT shows us how to turn Second Skin Spectrum in to Sludge sound deadener

  • Making Second ...
    ANT shows us how to turn Second Skin Spectrum in to Sludge sou...
  • The effectiven...
    Here I show how effective Spectrum Sludge is at reducing vibra...

Product Reviews

Write Review

  1. needs to be applied thick 3 Star Review

    Posted by on 21st Oct 2015

    It does work to dampen resonant body parts, but it needs to be applied thick, at least 3 mm to be effective.

  2. Good for auto applications 5 Star Review

    Posted by on 14th Nov 2013

    I used this on my 1970 Mustang, particularly the rear wheel wells to recreate the "factory" sound deadener look. The product arrived promptly and was easy to use. I used a paint brush to apply it with and without the activator. With the activator, it firmed up well, and quickly. One advantage as well is that it is not really smelly like other products. It dried nicely (takes several days if applied heavily like I did) and looks like I wanted!

  3. BMW M3 Sound insulation 5 Star Review

    Posted by on 16th Jul 2013

    I had to change the trans on my 98 BMW M3. It had a fabric sound insulation there which breaks down after a few yrs and then it starts to sag and starts rubbing against the drive shaft. I wanted something better that wasn't going to break down and came to know of the Sludge. I had the installer put it on and it dried within 20 mins. When I drive I hear no excess noise. Very happy w/ the product and highly recommend. Just wish the shipping was a little cheaper.

  4. Great!!!!! 5 Star Review

    Posted by on 4th Jun 2013

    This product is great but the only downside is it takes a full week to dry....

  5. Sludge is the way to go 5 Star Review

    Posted by on 8th Feb 2013

    After watching the Second Skin video on Sludge I thought this stuff is too good to be true. But it isn't. It is amazing stuff. It was applied to the floor pans of my 1967 Mercedes where it not only lessen the outside noises but appeared to strengthen them. I definitely would recommend Sludge and any other products from Second Skin. Customer service is awesome as well.

  6. After reading what everyone is saying on the forums... 5 Star Review

    Posted by on 6th Nov 2012

    I purchased Second Skin Sludge. After reading what everyone is saying on the forums, seeing the prices and liking the website, I figured I’d give it a shot. Customer service is awesome. Before ordering, I sent several emails regarding the various products and all of my questions were answered. Installing the product was simple enough. I will be ordering a couple gallons more of sludge and some Damplifier Pro so I can line the doors, roof and wheel wells before I have my system installed. Great product and great customer service. Good job Ant.

  7. How quiet the car has become 5 Star Review

    Posted by on 6th Nov 2012

    Man o Man.... Anthony.... Thank you so much for your recommendation to go for the sludge product.... I just completed doing the 4 wheel wells in my 2001 maxima GLE. I used one gallon of sludge and did not even do the full wheel well. I just did the passenger compartment facing sheet metal upto the strut tower where the passenger compartment ends. I also made sure I laid the sludge kind of thick I know its more than 3mm. I took her out for a drive today and man I'm blown away. The tire noise from the back of the car has disappeared. Even my wife today commented as to how quiet the car has become. Thank you once again sir. I think I am going to go ahead and save up some money to sludge the wheel wells of my 330ci next...