About Paint Strippers

Paint strippers are a class of liquid or semiliquid solvents that soften and aid in the removal of paint so the underlying surface can be restored to its original state, or recoated like new. For decades, all paint strippers were very corrosive, and users had to be extremely careful to avoid contact with skin or mucous membranes. Modern paint strippers now come in a range of more environmentally friendly formulas, and many are gentler to the skin and surrounding surfaces while still being effective at removing layers of old paint.

Types

For many years, the main active ingredient in paint strippers was methylene chloride. Mildly corrosive to skin, it can cause chemical burns within a minute of contact. The main danger with methylene chloride is that it converts to carbon monoxide when inhaled and can cause carbon monoxide poisoning. It has also been known to cause heart attacks and is a suspected carcinogen. Despite this, it is still a widely used and effective ingredient in paint strippers, but there are now other choices. Strippers made with sodium or calcium hydroxide are known to be environmentally safe and have no significant health risks associated with their use. Orange oil, also known as limonene, is another fairly safe ingredient used in paint strippers today, and while it can cause skin irritation, it takes prolonged and repeated skin exposure to cause harm. When choosing paint strippers, read the chemical ingredient data on the container and follow all safety directions.

Function

All paint strippers work by dissolving and softening the paint so it can be either mechanically or hand-removed from the underlying surface. Primarily, the molecules in the stripper soak into the paint and cause it to swell or bubble up so it can be scraped away. Some paint strippers are heavy gels, designed to cling to vertical surfaces. All strippers must remain on the old paint for some time to work.

Considerations

The procedure for paint strippers is essentially the same, no matter what the active ingredients are. The stripper is brushed onto the surface, usually with a natural bristle applicator since it will melt synthetic bristles. It is brushed on quickly, in one direction only, because excess brushing allows the active ingredient to evaporate. It is left on the surface for 10 to 30 minutes, during which time the old paint will start lifting and bubbling. If there are multiple layers of paint, it can take several applications to remove it all. Depending on the underlying surface, a thorough cleaning with copper wool or soft scrub brushes is usually required to remove all traces of the stripper.

Effects

Paint stripper can be used on most coatings, not simply paint. It works as well on oil-based paints as on latex. It also works well for clear finishes like varnishes, lacquer and shellac. Some formulations of stripper will also penetrate deep into the wood to remove stain, although the successful outcome depends on the type of wood. Soft or open grain woods like pine and oak soak up more stain than harder woods like maple or cherry, and the end result may not be as pristine as new wood.

Warning

Always follow directions for the product you are using. Many paint strippers are highly flammable, and all must be used with adequate ventilation. For most, you must wear gloves and long sleeves to protect your skin from chemical burns. It is also wise to cover adjacent surfaces and flooring to protect them from inadvertent splashes of stripper.

Expert Insight

If it is impractical to use a chemical paint stripper, another alternative is a heat gun, which also can soften and lift old paint. This is a less-messy method, but it is usually more labor intensive. Additionally, great care must be taken when working around wood or flammable materials since the forced hot air can ignite dry wood.