Paint stripper can be used for a number of projects whether you are removing paint from brick, refinishing an old table or repainting a classic car there are times when using a liquid stripper is both faster and more effective then sandpaper or other mechanical methods of paint removal.
Because there are so many different types of coatings from varnish to urethane paint there are different formulations and methods to tackle each project. First we should understand what stripper is and the basic types available.
Gel, Liquid or Paste
It is expected that 90 percent of the work you do will be with a Gel or thickened stripper. Gel type strippers will stick to the surface they are applied to and will work fairly well on vertical surfaces but their biggest benefit is that they don’t splash as much.
Liquid strippers can be used on varnish or light finishes and can be applied with a rag instead of a brush but liquid is really better for dipping.
Paste type strippers which look similar to cake frosting can be applied to wood products to remove lead on moldings and other items while they are in place. This is a decent feature when removing the part will damage it but you will still need a drop cloth and protection while you work. It is also much more expensive.
What Is Stripper
Most people understand what an acid is and that it can be used to dissolve metals and other products. Well stripper is exactly opposite it is a strong alkaline. You can think of it as a lemon being acid and sugar being an alkaline.
The reason an alkaline like methylene chloride is used instead of an acid is because finishes are resistant to acids and the materials that they protect are not. If you were to use an acid strong enough to eat the paint off of a car fender it would also quickly eat the metal of the fender. This is not to say that Alkalies can’t also eat through metal because they can and the easiest metal for them to eat through is aluminum. Unless you know what you are doing you shouldn’t use strippers on aluminum. Stripper on aluminum can actually cause a fire so don’t throw the foil wrapper from your burger at lunch into the stripper waste container.
Strippers can cause very serious chemical burns. Unlike fire or electrical burns, when chemical burns start you don’t feel it until its too late. You should always use rubber gloves, full length clothing, have proper ventilation or a respirator and ALWAYS use protective goggles that will seal completely around your eyes. Don’t think that basic safety glasses are enough. If stripper gets in your eyes it will continue working for hours and there is a high likelihood that you will go blind. For this reason unlike any other project bad safety when using stripper is as bad or worse then using a cutting torch without eye protection.
NOTEthere are some non-caustic strippers out on the market. Their performance will vary and read their directions for safety procedures.
There are many times when you need to get your work done fast and stripper can remove all of the finish in less time and with less damage then any mechanical paint removal process.
There are also times when stripper can be used to remove lead based paints from decorative moldings and other detailed pieces leaving the part safe for your home.
The Basic Rule of Stripper
Brush it on in one direction, with one stroke and don’t disturb the area again until the stripper has done its work. The best thing to do is allow the stripper to stay on the part as long as you can or until it has removed the finish.
To work the stripper must remain wet so never work in direct sunlight or on a hot surface. Some people put a heavy plastic painters tarp over the stripper to keep it wet overnight but it becomes pretty messy.
Always work out of a plastic work container not the original container.
Plastic brush bristles will melt and natural fiber brushes will be ruined so use cheap disposable brushes.
Stripper should take a couple hours not minutes to work so let it be.
You can test how the work is progressing with a plastic scraper. If not immediately then within about an hour the paint will start to lift and bubble. If you have primer under the paint then it will require more time to eat through that.
Once most of the paint has softened you can use a plastic scraper to remove the bulk of the paint. A cardboard box with a plastic bag in it will be helpful for getting rid of the stripper and to clean the scraper on the edge of the box as you work.
More then likely there will places that need a second coat. Repeat the process of applying stripper and scraping the finish off.
Once you are pretty happy you will need to neutralize the stripper with water. You should understand that water will lift the grain on your wood making it rough but the stripper needs to be deactivated or it will cause you problems when you apply your new finish and may also damage the part.
On Metal Products some people suggest that after the water bath you wipe the area down with metal prep which has an acid in it. This is a good idea but you should really wait until after you have gone over the area with sandpaper to remove all residue and prepared the metal for primer.
Wood chairs and other small items can be placed in a stripper bath to remove old finishes. This is usually only done at a professional shop because of the volume of chemicals needed. Finding someone that can do the work is also getting more difficult as more restrictions and safety procedures have put a lot of furniture restorers out of business. If you have an expensive mantle or picture frame it may be worth the effort and cost.
Ok so I hope that I have scared you away from using strippers because they are a dangerous product. The fact that you will go on and actually use them means need to and don’t want to and this is how it should be.
Strippers are a great tool and will help you get work done that you just can’t get done with sanding or heat guns and scrapers. They are also an option when media or sand blasting isn’t.
But you should think of stripper as you would walking through a swimming pool with a plugged in radio over your head. If you make it… then you’re in the pool you got your music and everyone is happy. If you have a few beers before you cross that pool… well its not going to be pretty.
The YouRepair Store Sells a variety of different paint removal tools and stripper products.