
Paint stripper or paint remover is a chemical product designed to remove
paint
Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are ...
,
finishes, and
coating
A coating is a covering that is applied to the surface of an object, or substrate. The purpose of applying the coating may be decorative, functional, or both. Coatings may be applied as liquids, gases or solids e.g. powder coatings.
Paints ...
s, while also cleaning the underlying surface. Chemical paint removers are advantageous because they act on any kind of geometry and they are cheap. They can however be slow acting.
Paint can also be removed using mechanical methods (scraping or
sanding
file:Schleifpapier verschiedene Sorten.jpg, upright=1.35, Sheets of sandpaper with different grit sizes (40 (coarse), 80, 150, 240, 600 (fine))
Sandpaper, also known as coated abrasive or emery paper, is a type of material that consists of sheet ...
) or heat (
hot air
''Hot Air'' is a conservatism in the United States, conservative American political blog. It is written by Ed Morrissey, John Sexton, and David Strom. Karen Townsend and Jazz Shaw wrote for the blog until their deaths in 2024. The pseudonymous ...
,
radiant heat
Thermal radiation is electromagnetic radiation emitted by the thermal motion of particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation. The emission of energy arises from a combination of electro ...
, or
steam
Steam is water vapor, often mixed with air or an aerosol of liquid water droplets. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization. Saturated or superheated steam is inv ...
).
Types
The selection of chemical paint removers is based on the chemical bonds that form the paint's binder. Two basic categories of chemical paint removers are caustic and solvent.
Caustics
Caustic paint removers, typically aqueous
sodium hydroxide
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions .
Sodium hydroxide is a highly corrosive base (chemistry), ...
(also known as lye or caustic soda), work by breaking down the
chemical bonds
A chemical bond is the association of atoms or ions to form molecules, crystals, and other structures. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds or through the sharing of electrons as ...
of the paint, usually by
hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...
of the esters that comprise the paint film.
[ Caustic removers must be neutralized or the new finish will fail prematurely. In addition, as caustic paint strippers typically include corrosive active ingredients, several side effects and health risks must be taken into account in using. Caustic aqueous solutions are typically used by antique dealers who aim to restore old furniture by stripping off worn ]varnish
Varnish is a clear Transparency (optics), transparent hard protective coating or film. It is not to be confused with wood stain. It usually has a yellowish shade due to the manufacturing process and materials used, but it may also be pigmente ...
es, for example.
Solvents
Solvent-base paint strippers can be complex mixtures of various organic solvent
A solvent (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for p ...
s, emulsifier
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Althou ...
s, thickening agents, alkaline or acid active ingredients as well as evaporation and corrosion inhibitors. Dichloromethane
Dichloromethane (DCM, methylene chloride, or methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odor is widely used as a solvent. Although it is not miscible with ...
, also called methylene chloride, is a popular solvent, but its use has been declining because of health concerns.[ Traditional solvent paint strippers penetrate the layers of paint and break the bond between the paint and the object by swelling the paint.]
Aside from dichloromethane, some popular stripping solvents are N-methylpyrrolidone, dimethylformamide
Dimethylformamide, DMF is an organic compound with the chemical formula . Its structure is . Commonly abbreviated as DMF (although this initialism is sometimes used for 2,5-dimethylfuran, dimethylfuran, or dimethyl fumarate), this colourless liqui ...
, benzyl alcohol
Benzyl alcohol (also known as α-cresol) is an aromatic alcohol with the formula C6H5CH2OH. The benzyl group is often abbreviated "Bn" (not to be confused with "Bz" which is used for benzoyl), thus benzyl alcohol is denoted as BnOH. Benzyl a ...
, and dimethyl adipate. None of these are chlorocarbons.
Paint strippers come in a liquid, or a gel (" thixotropic") form that clings even to vertical surfaces.
Solvent strippers may also have formulations with limonene
Limonene () is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the essential oil of citrus fruit peels. The (+)-isomer, occurring more commonly in nature as the fragrance of oranges, ...
(obtained from orange peels) (or other terpene
Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n for n ≥ 2. Terpenes are major biosynthetic building blocks. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predomi ...
solvents). Nitromethane
Nitromethane, sometimes shortened to simply "nitro", is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a polar liquid commonly used as a solvent in a variety of industrial applications such as in ...
is another commonly used solvent. Dimethyl sulfoxide
Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula . This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is ...
is a less toxic alternative solvent used in some formulations. Unfortunately, these alternative stripping formulas are less effective compared to those based on dichloromethane.
Alternatives
Heat guns are an alternative to chemical paint strippers. When heated, softened paint clumps and is easier to contain. High-temperature heat guns at or more create toxic lead fumes in lead-based paint, but low-temperature heat guns and infrared paint removers do not create lead fumes. Fire is a possible hazard of using heat guns.
Steam can be used on large surfaces or items to be stripped, such as window sash, can be placed inside a steam box.
Safety
A product's material safety data sheet
A safety data sheet (SDS), material safety data sheet (MSDS), or product safety data sheet (PSDS) is a document that lists information relating to occupational safety and health for the use of various substances and products. SDSs are a wide ...
can provides more safety information than its product label
A label (as distinct from signage) is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product. Labels are most often affixed to packaging and containers using an adhesive, or sewing when affix ...
s.
Many traditional paint strippers were or are based on dichloromethane
Dichloromethane (DCM, methylene chloride, or methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odor is widely used as a solvent. Although it is not miscible with ...
, which can pose serious health risks and is banned in the United States and European Union for consumer use. Despite this, deaths from dichloromethane are extremely rare at fewer than 2.4 cases per year and associated mostly with users applying large amounts in confined, poorly ventilated spaces. When applied in reasonable amounts and with typical levels of ventilation, or outdoors, it is generally safe to use.
Removing old lead-based paint can disperse lead and cause lead poisoning
Lead poisoning, also known as plumbism and saturnism, is a type of metal poisoning caused by lead in the body. Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, infertility, numbness and paresthesia, t ...
, leading several US workplace and environmental regulations to address removal of old paint that could contain lead.
See also
* Distressing
* Nitromors
References
External links
JAIC 1993: The composition of proprietary paint strippers
Old-House Journal article on paint removers starts on page 58
a paper on the history of NYC graffiti.
"How To Use Paint Stripper"
an explanation on usage of paint strippers
Remove Old Paint from Walls
{{Woodworking, expanded
Household chemicals
Industrial processes
Painting materials
Woodworking