I've used chemical strippers, heat guns, pressure washers, sandblasters, power sanders, scrapers and plenty of elbow grease to remove paint. Although some newer products are decidedly safer and specialty tools have improved, each paint removal path still has its ups and downs.
Paint is a little like body weight: It's a lot easier (and more fun) to put it on than to take it off. And there probably are as many approaches to shedding unwanted layers. The three types of methods for removing finishes are: chemical strippers, mechanical means and heat. To select the best strategy, consider these factors:
- The type and thickness of the coating
- The location of the workspace
- The orientation, intricacy and composition of the surface to be stripped
No matter the approach, paint removal is messy and potentially dangerous work. First, there's a 75 percent chance that pre-1978 coatings will contain lead, which can poison your brain and organs or create an environmental hazard if not handled carefully. Second, old-school solvent-base paint strippers carry warnings of cancer, skin burns, respiratory problems and flash fires.
Before using a power sander to remove finish from decking, sink the fasteners so they don't catch and tear the abrasive belts. When using a portable belt sander, hold the tool at a 45-degree angle to the wood grain as you move along each deck board. This speeds the process, creates a uniform look and produces enough roughness for the new finish to grab.
Softening coatings with chemical strippers and using various tools to scrape off the goo is the most common way to remove paint and finishes from furniture and intricate surfaces, especially if the coatings contain lead. For large, flat exterior surfaces such as wood decking or clapboard siding, power sanding and power planing are good options. (High-pressure sand blasting or low-pressure mist/volcanic glass blasting are best left to professionals.) Pressure washers are okay for removing loose (lead–free) paint; but never use one to strip adhered paint.
Using sanders and scrapers
I like to use a power sander to get old deck boards or flooring down to bare wood for refinishing. First you must set fastener heads, such as nails, below the surface. Use a walk-behind floor sander (typically used for interior floors) fitted with a dust collection bag and 80-grit abrasive to remove semi-transparent stains. (For a thicker paint film, start with 60-grit.)
There are specialized powered paint removal tools, such as the Paint Shaver-Pro that plane paint from the face and the butt of clapboards, sucking the chips and dust into a HEPA vacuum. (It can sheer off nail heads; so be sure to set the nails and limit the cut depth to the coating thickness.) Afterwards, smooth the surface with a random orbit sander.
A contractor experienced with the PaintShaver Pro shared these tips:
- For a smooth horizontal flow and uniform passes, work from a plank rather than a ladder.
- The cutter that shaves the clapboard butts can produce a wavy edge as you free-hand your way along the surface. To touch up uneven butts, dial the face-cut depth to zero and make another pass along the edge.
PaintShaver Pro is available at some rental centers, but if you're stripping paint from an entire house, it may cost less to buy one at $500 to $600.
Another powered paint removal tool that is easy to control and less expensive ($79), is the the Wagner PaintEater. It uses a tough fiber disc to safely remove paint without cutting into the substrate.
Using chemical paint strippers
The advantage of chemical strippers is that they can remove multiple layers of coatings without damaging the underlying surfaces or releasing dust or chips. Products vary in viscosity: liquid, gel or paste. The liquid strippers are suited for penetrating intricate, horizontal surfaces; a paste or gel stripper is best for flat or vertical surfaces.
Use disposable brushes to apply chemical strippers; then remove softened finishes with scrapers, stiff brushes and abrasive pads. Careful disposal of the residue is important, especially if the paint of varnish contains lead. Check your state's lead-disposal policies before you begin stripping.
Chemical stripper makeup - Finish removers all contain radically different chemicals, so be sure to read and follow instructions for the product you're using. Those made with flammable solvents, such as toluene or acetone, should always be applied outdoors. Their volatile organic compounds (VOCs) are heavier than air and settle in low areas. In a basement workshop, for example, the product's fumes can collect around a nearby water heater and cause an explosion.
To narrow your choice of stripping products, read the label's recommendations regarding appropriate work surfaces and finish coatings. If you are unable to work outdoors, be sure to use a nonflammable product.
If you must remove a finish indoors, cover the floor with plastic and newspapers and protect yourself with an organic cartridge respirator, chemical resistant gloves and eye protection. Always open windows and doors to allow for cross ventilation.
The safer strippers are made with caustic chemicals such as N-methyl-pyrrolidone (NMP) or with organic ingredients, such as soy. In general, the milder the ingredients, the longer it takes to break down a finish. In fact, the most effective ingredient isn't in the bottle or can; it's the patience you bring to the project. Some can take 24 hours to soften thick coatings; they may even take two applications or the use of different products to remove all of the layers -- especially when multiple oil-based layers lurk under water-based layers.
Chemical stripper technique - Although the manufacturer provides time guidelines, remember that stripping paint is a little like microwaving popcorn: You need to periodically check on the progress, but resist the urge to remove the softened coating until the chemical has done its job. Never let strippers dry on the surface; they work only when they are wet. While many products contain wax to retard evaporation, you can extend the dwell (working) time by:
- Applying a generous amount of product
- Moving the brush in only one direction to not disturb the surface
- Covering the freshly applied stripper with ordinary wax paper (or for large areas, inexpensive 2 mil painter's plastic)
On that point, Peel Away provides a paper mat to embed in the coating. The mat impedes evaporation while consolidating multiple layers of softened coatings for neater removal and disposal. This is particularly helpful when stripping coatings containing lead.
Softened finishes are best removed from flat surfaces with a plastic putty knife – particularly if you plan to stain or varnish the piece. Avoid using metal scrapers, which can burnish the surface and impede the penetration of oil stains. Keep in mind that sanding of fine antiques after stripping can remove the patina that gives the surface its aged character.
After one or two heavy applications, repeat with an additional (lighter) coat to soften and remove residue. With less material to eliminate, expect a shorter dwell time. With a soft brass brush, stripping pad or a toothbrush soaked in stripper, remove the last bits of finish. Neutralize and clean the surface using a product recommended by the stripper manufacturer (such as mineral spirits, acetone or vinegar) again, in adequate ventilation.
Using a heat gun
Never use heat to remove lead paint because it can turn the heavy metal into poisonous fumes that can be inhaled. Because of the potential for fire, heat guns are risky for stripping siding and trim. Infrared heat plates such as the Silent Paint Remover are safer, but they can be tiring to hold in place on vertical surfaces.
To avoid burn marks when stripping paint (only lead-free coatings) with a heat gun, keep the gun in motion while holding it near the surface. As soon as the paint softens and starts to blister, begin lifting the film with a metal scraper or putty knife.
This project is part of HANDY's Top 5 Collection: Painting Tips.
Click here to check out the other four painting articles in this collection.