Methods on Removing Paints
View more related buyers guides
Published by TOP4 Team
The traditional way of removing paint is by abrasion, normally in the form of abrasive paper. A number of materials are available and, in the main, abrasive materials are for small surfaces, or for finishing and smoothing off after the major part of the paint has been removed by other methods.
Sandpaper is best used with a cork or softwood block, to ensure smooth surfaces. It tends to clog up with paint, but is available as ‘Openkote’ or ‘No Fil’, meaning that particles are spaced further apart, thus stopping early clogging with paint debris.
Sandpapers can also be fixed to machines such as orbital sanders or belt sanders. The orbital sander takes sheets of paper, but should be considered as a finishing sander only — it doesn’t do a great job of removing thick coatings of paint. The belt sander uses a continuous belt of abrasive fabric, and cuts very quickly indeed.
A number of grit sizes are also available. The coarse ones will tend to deeply scratch surfaces and the finer ones polish surfaces. For most jobs sizes will be useful.
Scrapers are available in a number of forms for removing paint. These tend to skate over good paint surfaces, so are not easy to use on paint with few blemishes. A shave hook is a triangular or multiform scraping tool with a handle, which is great for smaller jobs such as windows and mouldings. All forms of scrapers work best if the paint is first softened by heat or chemicals.
A number of mechanical strippers are available. Electric disc sanders, belt sanders, wire brushes, and purpose-made sanding machines are all common enough. In some instances, such as concrete or masonry, an angle grinder may even be considered. Wire brushing is mainly used for stripping paint off metal and masonry.
Using Heat to Remove Paint
It has long been known that heat will soften paint to make it easy to scrape. However, softening doesn’t mean burning, which is what easily happens with a blow torch.
Blow torches, which can create a fire hazard, should be used with great caution. The problem is that scrapings already warm or hot from heating are highly flammable, and a blow torch has an actual flame. So, don’t use a blow torch without some kind of extinguisher close by.
Hot air guns are a fairly recent innovation. They were originally developed for the plastics industry, where they are useful for bending and welding plastics. But they can also melt paint films. They are available from better handyperson hire centres.
The only other thing you will need is a scraper to remove the softened paint. If the project is large, sharpen the scraper edges regularly so that removal is easier. For smaller areas a shaving hook is also useful.
Chemical Stripping of Paint
Chemical paint stripping is not economical over large areas of a house, unless bulk caustic soda, a dangerous substance, is used. It is more suited to small, detail work, or where heat or mechanical abrasion is impossible.
The two main chemicals used are caustic soda, and methylene chloride-based, strippers. Caustic soda is bought as crystals which are dissolved in water. This generates heat, and the solution can burn skin, so extreme caution is necessary.
Methylene chloride is the proprietary type of paint stripper, and not quite as nasty. Both materials may cause minor burning of timber, and the timber can end up somewhat greyish.
For both, wear gloves and other protective clothing. Store materials away from where any non-readers of labels are likely to interfere with them. Both are applied to the paint with a brush, and after a short period, the softened paint can be scraped off and discarded. Caustic soda will destroy bristle brushes.
Where chemical paint stripping has been used, it is important to neutralise the surface before repainting. Otherwise the residue of the stripper will simply cause the new coating to flake off. Neutralisation can be carried out with white vinegar or mineral turpentine.