Chemical paint remover work only on certain type of finishes, and when multiple of finishes may have been used on any particular surface, trial-and-error testing is typical to determine the best stripper for each application. Two basic categories of chemical paint removers are caustic and solvent
Caustics paint remover, typically sodium hydroxide ( also known as lye or caustic soda ), work by breaking down the chemical bonds of the paint, usually by hydrolysis of the chain bonds of the polymers forming the pain. Caustic removers must be neutralized or the new finish will fail prematurely. In addition, several side effects and health risks must be taken into account in using caustic paint removers. Such caustic aqueous solutions are typically used by antique dealers who aim to restore old furniture by stripping off worn varnishes, for example.
Solvent paint strippers penetrate the layers of paint and break the bond between the paint and the object by swelling the paint.
The principal active ingredient in common solvent paint strippers is dichloromethane, also called methylene chloride. Methylene has serious health risks including death and is likely a carcinogen.
Solvent strippers may also have formulations with orang oil ( or other terpene solvent ),
n-methylpyrrolidone, esters such as dibasic esters (often dimethyl esters of shorter dicarboxylic acids, sometimes aminated, for example, adipic acid or glutamic acid), aromatic
hydrocarbons, dimethylformamide, and other solvents are known as well. The formula differs according to the type of paint and the character of the underlying surface. nitromethane is another mommonly used solved. Dimethyl sulfoxide is a less toxic alternative solvent used in someformulation.
Paint strippers come in a liquid, or a gel (“thixotropic”) form than clings even to vertical surfaces.
The principle of pain strippers is penetration of the paint film by the molecules of the active ingredient, causing it to swell; this volume increase causes internal strains, which, together with the weakening of the layer’s adhesion to the underlying surface, leads to separation of the layer of the paint from the substrate