When starting a restoration project, a paint removal method is often one of the first decisions that need to be made. This choice impacts all the work the comes after, so it is an important first step that can lead to the best results or the worst, no matter the materials and coatings used afterwards.
There are many options, some that do more harm than good, so this article attempts to review them in turn, discuss both positive and negative attributes, as well as safety, surface prep, and the Earth and Flax recommendations when using the traditional, natural, oil-based finishes.
Listed below are the primary paint removal methods, starting with the least recommended and closing with the best suggestion, based on 20+ years of experience of the Earth and Flax team: infrared.
The mess after chemical stripping agents were used to remove paint on columns in VA.
Chemical Stripping Agents
Chemical paint removal options are the least preferred method of paint removal from the Earth and Flax perspective. The marketing for these products often pitch that they are "greener" and somehow safer to use than other methods, but any formulation that removes paint is not going to be safe or healthy to use.
Always wear gloves and proper safety gear.
There is also an assumption that these products are more economical and faster, requiring less time than other paint removal options. We would argue that is not the case. Multiple applications are often required to get down to bare wood. The application and removal of the paste or sheets of stripper are messy, often have a strong odor, and surfaces are hard to clean afterwards.
In addition to those factors, the primary reason we strongly discourage chemical strippers is that once introduced into a porous wood surface, you have forever changed the composition of the substrate. You can never truly extract that formulation from the wood once introduced, meaning it is very difficult to truly neutralize these chemical compounds. Even after washing, rinsing, and repeated cleanings, these stripping agents can leech out of the wood substrate, especially with temperature fluctuations and seasonal changes, damaging the painted finish. This is true if you use a modern, petrochemical-based paint or a natural, oil-based Linseed Oil Paint.
Pros: None. Maybe the only option on some substrate types such as metal or masonry, that must be stripped in situ.
Cons: Messy, inefficient, and damages the integrity of the substrate, especially a porous wood surface.
Paint Shaver or Grinder
Paint shavers and grinders are another method that is sold as being a faster, more efficient paint removal option but one that we would argue is not worth the potential damage and mess. While, some may be able to use these tools with care and get a decent result, most users will not be able to avoid removing some percentage of surface wood, impacting the overall integrity of the wood substrate in the process.
Some users have even found that these methods damage the fasteners or nails that hold the siding to the wall, leading to the need to reattach the boards. Tapping nails down before operation can improve results, but the other downsides make this method highly inadvisable.
Another drawback with this method is the texture created in the process since these methods are literally cutting into the wood surface. A shaver can show where the passes start/end or snipe. A grinder can create a highly noticeable swirl pattern. If sanding to even out the wood surface is required, any time savings for the project is lost. Sanding is highly inefficient and removes more wood from the surface in the process. If the patterning is left, no modern or traditional painted finish will cover this completely and the shaver or grinder method will be evident after restoration is complete (show in image above).
Finally, using such power tools is messy, causing chips and debris to become airborne, including potentially lead based debris, which consequently makes collection and disposal more difficult.
Pros: None.
Cons: Messy and damaging to the wood surface, often leading to the need for more sanding to avoid visible patterning or swirl marks.
Blasting (Sand, Particulate, Corn, Ice, Sponge, etc.)
While some types of blasting can be very useful for metal restoration products, old cast-iron radiators for example, it is not as common for wood substrates. This is partially the case because it is just not that practical to bring such equipment to a site, but it also has similar downsides to a paint shaver or grinder (above).
Blasting can remove or damage the wood surface, even if great care is taken, and can leave an unnatural patterning or pitting of the wood. Visually, this can be unsightly and it can greatly impact the integrity of the timber in the years to come.
It may seem faster but again, if excessive sanding is required to even out the wood surface, then it is not a timesaver and additional sanding removes even more wood in the process.
Finally, blasting can be a mess to clean up. Even if it is an environmentally-friendly particulate like sand or corn, it will be difficult for users to remove all used matter from the surrounding area easily. Many particulate or sponge blasting involves petrochemical polymers, which are almost impossible to clean-up after landing in the surrounding grass, contaminating green-spaces with high-levels of micro-plastic waste.
From the Earth and Flax perspective, blasting is just not worth the potential harm possible to a wood substrate. It is irritating at best for the homeowner and an environmental/human health risk at worst.
Pros: Appropriate for certain metal substrates, like cast iron radiators.
Cons: Messy and damaging to the wood surface, often leading to the need for more sanding to avoid visible patterning or pitting. Clean-up can be a concern, with some particulate options being a health and environmental hazard.
Steam (Steam Boxes or Hand-Held)
A very common paint removal method for window restoration over the last 10 years or so, steam is rarely used on large exterior restoration projects as it is just not that practical. Steam is seen as a safe and relatively gentle method to loosen old paint and putty with little damage to the old wooden sashes. Perhaps if operating temperatures are kept low and the sashes are not left to heat for long periods of time, this method can be used successfully. Some folks swear by it in their restoration work.
The hesitancy we have with this method is that steam is moisture and moisture is the enemy of wood in terms of preservation of the substrate over time. To use a method that craftspeople literally use to bend (steam bend) wood purposefully simply to remove old coatings, seems a little risky and counter-productive.
Our primary concern is the warping of the sash and this warping can occur over time. Even if the sashes, once fully restored, fit back into their openings without any issues, they may warp and bend in place over time after being exposed to such high levels of moisture. This is even more concerning if a modern, barrier-forming coating is used, like a conventional acrylic or latex, especially if the sashes do not have enough time to dry out completely after being exposed to high levels of heat/steam and before being painted with a conventional, modern coating.
Proceed with care and consider another method of removal. If you insist on the use of steam, be sure to allow the wood enough time, several weeks is ideal, to fully dry out before painting and completing the final restoration steps.
Final concerns for this method are that steam boxes can get very hot. Hot enough to cause lead fumes to be released. Keep boxes clean of paint chips and debris and keep track of temperatures to avoid hazards to human health during operation.
Pros: Does not generally cause physical damage to the wood surface during paint/putty removal as only gentle scraping may be required.
Cons: The main concern is the impact of moisture on a porous wood substrate and the potential for warping and bending now and over time. Another downsides is high moisture content if not enough time is allowed for the wood to dry out completely before proceeding.
Heat (Heat gun or torch)
The primary downside of a heat gun is that it only heats the surface of a small area at a time and can have a high risk of charring or burning the wood. Most heat guns have a high operating temperature and so therefore a high risk of vaporizing lead in the paint removal process. Most models are very loud (many similar to a hair-drier when in use) and consequently tedious to use for long periods of time.
To summarize, a heat gun is inefficient, loud, has a high risk of wood surface damage, and significant concerns in terms of human health.
There are heat gun models that have a built-in temperature gauge that allows for safer use. If you are just getting started, want to test a painted surface to confirm if the coating responds to heat before investing in an infrared tool, or if your project budget will only cover something in this price-point, a heat gun with a temperature gauge might be a good fit. Even with a temperature a gauge, we highly recommend using such a tool with caution.
A torch is similar but even more risky as it is an open flame. A major fire hazard and a method to avoid completely.
Do not use a torch - it is a major fire hazard.
Pros: A heat gun is cheap and if used with care, acceptable results are possible.
Cons: High possibility of burning the wood surface, inefficient, loud, and possible human health concerns based on the high operating temperature.
Scraping and Sanding
While we always recommend applying Linseed Oil Paint upon a bare wood surface whenever possible, some projects just do not have the time and budget to remove all of the old coatings. In this case, we would recommend a dry scrape and/or cleaning with a petrochemical-free liquid soap like Linseed Oil Soap. Scrub to remove dirt, dust, organic growth, any loose particulate, etc. and rinse well with hose water. Avoid power washing as it introduces too much moisture into a porous wood substrate. Once fully dry, you have the best possible scenario, given these conditions, to then apply several coats of Linseed Oil Paint.
Linseed Oil Paint is only as good as what it is applied upon, so if that old paint fails it will of course take the Linseed Oil Paint with it. Consequently, some touch-ups or a full restoration may be required in the years to come.
Sanding should always be limited as much as possible and sanding power tools should be avoided. Lead paint is of course a concern, as lead is the most dangerous to human health when it becomes a fine dust. We should also be concerned about the formulations of various other coatings that may be present on a project. The smaller that debris becomes, the easier it contaminates the environment, gets into the soil and ground water, gets tracked into the house and around the property/neighborhood. We want to try to keep debris in as large a form as possible, clean-up as we go, and dispose of waste in the appropriate manner. Always wear the proper safety gloves, gear, respirators, etc. when fine particulate is present, true for homeowner and professional alike. Be aware of your work clothes and shoes as well to avoid tracking dust and debris outside the work zone.
Note: Sanding paint, like the sanding of exterior wood cladding of an average house in North America, is banned in many states but rarely enforced. While awkward and uncomfortable, if your neighbor is sanding or has hired someone to sand the exterior of their house, we do highly recommend you ask them nicely to stop and pursue another paint removal method. Encourage them to consider the dust, especially if lead may be present but also a wide range of other possible particulates, that will blanket the neighborhood and get into adjoining yards, houses, cars, etc. especially where children and pets may be present.
This method is a signifiant danger for them as well and kind concern may be the best strategy to achieve a safer paint removal option moving forward. This is also probably your only option as acrimony generally only leads to poor neighborhood relations.
Overview: Always avoid sanding old paint. A dry-scrape and cleaning with Linseed Oil Soap is a possible approach to surface prep.
Pros: Scraping and cleaning is a inexpensive way to improve the appearance of a structure and potentially protect what is there, avoiding continued deterioration based on old coating/material failure.
Cons: Scraping and cleaning is often a stop-gap or bandaid solution and a full-restoration and removal of all old coatings may be required in the future. While decent results can be achieved with this method, an awareness of the limitations is important to understand before selecting this strategy.
Infrared Paint Removal
Infrared paint removal is the preferred paint removal method at Earth and Flax. Not only because it achieves a decent surface to then paint upon without cleaning, sanding, and further prep, but it also operates at a much lower and safer temperature, is almost soundless, and has a much lower chance of discoloring the wood surface.
Heat surfaces for an average of 30 seconds and scrape old coatings with a sharp scraper, preferably a long-handled scraper. Debris can range from large strips to medium sized chips of old paint that can be easily collected and disposed of properly. Do not over heat to the point the surface smokes or turns dark, as this is a sign you are heating too long.
Some small particulate is still possible, so always wear the proper safety gloves, gear, respirators, etc., true for homeowner and professional alike. Be aware of your work clothes and shoes as well to avoid tracking dust and debris outside the work zone.
Paint removal with infrared is still hard work and requires attention and patience to get the ideal result. It is importnat that the hard work that goes into this step of any restoration project gets you the best results possible without contributing to the deterioration or damage of the substrate you are working so hard to protect/preserve.
Read more about the infrared tools available at Earth and Flax, as well as dig deeper into benefits, operating suggestions, and videos on The Silent Paint Remover™ product page.
Pros: Safest, most efficient paint removal option based on the lower operating temperature and less risk of wood surface damage.
Cons: Takes time and patience to get the ideal result. See Tips & Tricks below to achieve best lifespan of the tool, as well as increase ease of use.
Infrared Tips & Tricks
To get the best results from your infrared tool be sure to keep your scraper blades sharp while you work – this is an important aspect to be as efficient as possible during the paint removal process. A dull scraper slows your work down considerably.
Be sure to let the unit rest from time to time, allowing the heat to escape (not flat on a surface such as a table or on the ground but with the bulbs reflected outwards) as this is the number one reason for tool damage and can be easily avoided.
Shield any surfaces you do not want to heat with aluminum tape or aluminum foil. A piece of cardboard wrapped in aluminum foil can be very helpful to protect glass, etc. Only the Putty Lamp does not require the shielding of glass.
Finally, if you have some stubborn dry paint, consider applying on some Purified Linseed Oil the night before paint removal as this will help reconstitute the old coating for easier removal, as well as to bind the dust for quicker disposal.
Usually, the more layers of paint the faster the infrared works.
Dampen and dispose of oil-soaked rags to avoid a fire hazard.
It is always advisable to wear proper safety gear, including a respirator. Dampen and dispose of debris as directed by your local community waste management location.
If you have questions always feel free to reach out: info@earthandflax.com.
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