What is it?

SLUDGE is the newest Tri-Art acrylic to hit the shelves. It is a by-product of acrylic paint manufacturing. It is the combination of the precipitated solids amassed from our wash water, which has then been re-processed into thick and thin acrylic paint formats.

The waste solids are made up primarily of assorted pigments, additives (such as calcium carbonate, coloured Mylar and matting agents) and dried acrylic particulate. These act as the colorant in this product. SLUDGE has the same handling qualities as regular acrylic paints and can be used as a paint, primer or paint medium. It is manufactured with 100% acrylic emulsion, is semi-opaque and contains a fine particulate giving it a lightly toothy texture.

Sludge is produced from the accumulated wash water from production. SLUDGE is predominantly neutral grey in tone as the combination of colours produced in the factory during this time period dictate its hue. Occasionally we use off-spec or factory spills to obtain the batch colour. No two batches are alike, thus we do not assign a colour name but rather refer to each edition by their Batch #.

How is it made?

SLUDGE is made through a process of flocculation, separation, pressing, filtration, re-dispersion, production and packaging.

100% of water used in the factory for clean-up processes goes into a waste pit and is then pumped into a storage tank. The water is chemically processed every two weeks by flocculating the washwater. The accumulated solids sink to the bottom of the tank (1). The clear water is then siphoned off and re-introduced into the plumbing system and used for cleaning. The remaining semisolid material is then pumped into a filter press (2) that compresses it at 9000 psi into what is called press cake. These cakes are then broken up and re-disperse into water to form an aqueous dispersion. The aqueous dispersion is re-filtered and is introduced into thick and thin acrylic paint bases. The resulting SLUDGE is then packaged, labeled and is ready for use.

Breathe it - or paint with it.

Tri-Art endeavors to make the most efficient use of its equipment, people and resources while staying in tune with environmental issues. At this point in the company’s development, every effort is being made to re-use and recycle whenever and wherever possible.

The production of acrylic paint generates a significant quantity of wastewater, as all of our equipment and tools are cleaned with water. By producing SLUDGE, we are able to keep 100% of the water used in cleaning out of the local sewage system. This amounts to more than 1500 US gallons per every two-week period.SLUDGE is our most expensive and time-consuming product to process and manufacture; however, by doing so we are keeping our liquid waste out of our water system and our solid waste from being incinerated. We are offering SLUDGE as a commercial paint product so that you can help us in our efforts to be responsible.

What can you use it for?

SLUDGE is an economical alternative to both a neutral ground and neutral colour. It can be used in the place of gesso when a muted base is desired. SLUDGE is semi-opaque and although grey in tone, can be used in small quantities as an opacifier or medium toned colour extender. The Thick SLUDGE has similar texture holding capabilities as our High Viscosity colours, while the Thin version is comparable to our Liquid line. There is a quantity of solid particulate in the paint, giving SLUDGE a light tooth that make it a suitable ground for mixed media applications. As this is paint made with 100% acrylic emulsion, it is comparable in character to other acrylics. Hence it is highly adhesive to a variety of surfaces, dries to a water resistant, semi-gloss finish and can be easily applied with painting tools.


Sludge may contain every product we manufacture. Each batch is sent to a lab for content testing. If there are traces of Cadmium or Nickel, this will be noted on the label as with all our other products containing these minerals.

Glossary of terms

Process by which clumps of solids in water or sewage aggregate through biological or chemical action so they can be separated from water or sewage.
Aqueous dispersion:
A liquid system in which very small solid particles are uniformly dispersed in water.
The destruction of solid, liquid, or gaseous wastes by controlled burning at high temperatures. Hazardous organic compounds are converted to ash, carbon dioxide, and water. Burning destroys organics, reduces the volume of waste, and vaporizes water and other liquids the wastes may contain. The residue ash produced may contain some hazardous material, such as non-combustible heavy metals, concentrated from the original waste.
Acrylic emulsion:
A water dispersion of polymers or co-polymers of acrylic acid, methacrylic acid, or acrylonitrile. Acrylic emulsions dry by evaporation of the water and film coalescence.

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