Painting over oil-based paint can seem daunting, but with the right preparation and materials it can be done successfully. Properly preparing the surface and choosing the appropriate type of paint are key to getting great results when painting over oils. This comprehensive guide will walk you through all the steps needed to paint over oil-based paints on walls, wood, and metal surfaces.
Determine if the Existing Paint is Oil-Based
The first step is to determine if the existing paint that needs to be covered is an oil-based paint or enamel. There are a few ways to test:
Check the Paint Can Label
If you still have the original paint can, check the label for indications that it is an oil or enamel paint. Key terms to look for are “alkyd”, “oil”, “oil-based”, “gloss enamel” or “alkyd enamel”. Any of these terms mean you are dealing with an oil-based paint.
Rubbing Alcohol Test
A quick test is to use a cotton ball or pad with rubbing alcohol and gently rub it on a small inconspicuous area of the painted surface. If the paint softens or dissolves, it is likely a latex or water-based paint. If the paint does not react, it is likely an oil or enamel paint.
Flame Test
Carefully waft a piece of sandpaper over a flame, then gently swipe the smoked/blackened side over a small area of the paint. Oil-based paints will leave a sooty, dark smudge. Latex paints will not smudge.
Once you have determined that the existing paint is indeed an oil or enamel, follow the steps below to prepare for painting over it.
Prepare the Oil Painted Surface
Proper surface prep is essential for the new paint to adhere well. Glossy surfaces need to be dulled, and all surfaces should be cleaned and lightly sanded:
Clean and Remove Loose Paint
Wash the walls with a diluted solution of TSP cleaner and warm water to remove any grease, dirt or grime. Use a plastic scraper and steel wool to remove any loose, flaking or peeling paint. Wipe clean with a tack cloth.
Sand the Surface
Lightly sand to dull and roughen any glossy areas. This will help the new paint adhere well. Use 120-150 grit sandpaper on walls and 220 grit on wood or metal. Vacuum up any dust.
Spot Prime Bare Areas
For any bare spots where old paint has been removed, spot prime with an oil-based primer to seal and prepare those areas for the new paint. Allow primer to dry per manufacturer’s instructions.
Tip: On walls, spackle small holes and sand smooth before spot priming.
Degloss and Etch Metal Surfaces
For enameled metal surfaces, use a deglosser/etcher solution to dull and create microscopic texture. Rinse and let dry before priming or painting.
Choose the Right Type of Primer
Priming over oil paint before painting is highly recommended. The right primer will block stains, provide grip for the new paint, and prevent potential reactions between incompatible coatings.
Oil-Based Primer
For best results, use a high quality, oil-based primer meant for covering glossy surfaces. Alkyd-based primers are excellent for sealing in stains from oil paints and creating a solid, uniform surface for painting.
Bonding Primer
Bonding primers are another good option as they are formulated to stick tightly to slick surfaces like enamel paints. They work well on walls, wood, concrete, metals and other glossy surfaces.
Tip: Tinting the primer close to your finish paint color helps increase hiding power and coverage.
Be sure to allow the oil-based primer to dry fully as indicated on the can before painting over it with latex or water-based paints. The recoat time is usually overnight.
Use the Right Topcoat Paint
Choosing the right paint finish and sheen is also key for long-lasting results painting over oils:
Latex or Enamel Paint
Use a high-quality latex or water-based paint as your topcoat over an oil-based primer. The exception is for metal surfaces, where an oil-based enamel paint is recommended for durability.
Satin or Semi-Gloss Sheen
Choose a satin, eggshell or semi-gloss finish, rather than a flat sheen. The subtle sheen helps resist stains and makes the surface washable. Gloss is difficult to apply evenly over old oil paints.
Stain-Blocking Paint
For covering stubborn stains that bleed through primer, use a latex paint formulated to block stains, usually called “stain-blocking paint” or “priming paint”.
Tip: Add a paint extender or floetrol to latex paints to improve flow and leveling over glossy or textured surfaces.
By using the right combination of primer and paint suited to the oily surface, you can achieve long-lasting results.
How to Paint Over Oil-Based Wall Paint
Painting over oil-painted walls in your home provides a fast way to revitalize a room with color. With proper preparation and application, you can easily paint over existing oil-based wall paints:
Fill Holes and Imperfections
Use a lightweight spackle to fill any small holes, cracks or surface defects in the walls. Allow to dry and sand smooth.
Sand Glossy Areas
Lightly sand any slick, glossy areas to dull and roughen the surface so the primer and paint adhere well.
Clean the Walls
Use TSP cleaner and water, then rinse to remove any grease or dirt on walls. Allow to dry fully.
Apply Oil-Based Primer
Roller apply a thick coat of oil-based primer designed for covering existing glossy paint. Allow to dry overnight before painting.
Paint Two Coats of Latex Paint
Using a roller with a 1/4″ – 3/8″ nap, apply two coats of high quality latex paint in your desired sheen and color, allowing proper dry time between coats.
Remove Painter’s Tape
Carefully remove any painter’s tape used to protect baseboards or trim. Touch up paint if needed.
With the right prep and application methods, you can achieve beautiful, long-lasting results painting over oil-based wall paints.
How to Paint Over Oil-Based Trim and Woodwork
Oil-based paints used on interior and exterior wood trim, cabinets, doors and furniture can yellow over time and need refreshing. With careful surface preparation, oil-based primer, and latex paint, you can successfully paint over oil-based finishes on wood surfaces:
Clean and Remove Loose Paint
Use TSP or other cleaner to remove any dirt or grease from wood surfaces, then rinse. Remove any cracked or peeling areas of old paint with scraper, sandpaper or steel wool.
Sand to Dull the Finish
Lightly sand to de-gloss, roughen and dull any slick surfaces where paint is adhering well. Use fine 220 grit sandpaper. Remove any dust.
Spot Prime Bare Wood
For raw wood and areas where old paint was removed, spot prime with a quality oil-based primer formulated for wood. Allow to dry overnight.
Apply Oil-Based Primer
Using a brush, roller or paint sprayer, apply a uniform coat of oil-based primer to the entire surface. Allow to dry per manufacturer’s instructions.
Paint Two Coats of Latex
Apply two coats of a quality latex paint in the sheen of your choice, allowing proper dry time between coats. Water-based alkyd paints also work well.
Preparing wood surfaces properly and using compatible primer and paint ensures your freshly painted wood finishes will look great and last a long time.
How to Paint Over Oil-Based Metal and Aluminum Surfaces
Previously painted metal surfaces coated in oil-based enamels require special preparation and painting methods to achieve great results:
Clean and Remove Loose Paint
Clean metal with a degreaser, then scrape, sand or wire brush to remove any peeling, cracked or loose enamel paint.
Use Deglosser or Etching Solution
Wipe liquid deglossers or etching solutions over metal to dull, etch, and create a “tooth” for paints to adhere to. Rinse thoroughly.
Spot Prime Bare Areas
Prime any bare metal areas with a suitable metal primer before coating the entire surface with primer. Allow to dry per manufacturer’s instructions.
Apply Oil-Based Primer
For best adhesion over enamels, use an oil-based bonding primer made for metals. Apply a uniform coat and allow to dry overnight before painting.
Paint with Oil-Based Enamel
Use a premium quality oil-based enamel paint for the topcoat on metals. Apply two coats for complete coverage and long-lasting protection.
Proper prep and painting methods allows for successful results when painting over oily enameled finishes on metal and aluminum surfaces.
How to Paint Over Oil-Based Paint on Furniture
Refinishing wooden furniture with an oil-based paint finish can give it a fresh, updated look. To paint over existing oil-based paint or enamel on furniture:
Lightly Sand Surface
Use 220 grit sandpaper to scuff and dull the existing glossy finish. Remove any dust.
Clean and Remove Loose Paint
Wipe furniture with a degreasing cleaner. Use a plastic scraper to remove any cracked, peeling or flaking paint.
Spot Prime Bare Wood
For raw wood areas, spot prime with an oil-based wood primer. Allow to dry per manufacturer’s instructions.
Apply Oil-Based Primer
Use an oil-based bonding primer designed for covering glossy surfaces. Apply uniformly and let dry overnight.
Paint withLatex Enamel
Use a high-quality latex enamel paint for your topcoat. Apply at least two coats for full coverage and a durable finish.
With the right primers and paint, you can easily paint over existing oil-based finishes on wooden furniture and give it a vibrant new look.
Tips for Successfully Painting Over Oil-Based Paint
Follow these helpful tips and tricks for getting the best results painting over challenging oil-based surfaces:
- Only paint when temperatures are between 50-90°F and humidity is below 85% for proper drying and curing.
- In hot, dry conditions, oil-based primers dry extremely fast. Use a primer extender additive to increase open time.
- Allow at least 2 weeks cure time before washing newly painted oil-based surfaces.
- Use high quality applicators like Purdy or Wooster brushes and microfiber paint rollers. Avoid cheap rollers that can leave lint.
- When spraying oil-based primer, wear a respirator and filter mask rated for organic vapors to avoid breathing fumes.
- Work in sections when painting over oil finishes to avoid lap marks. Maintain a wet edge as you go.
- If covering very dark oil colors with light paint, tint primers towards finish color for better coverage.
- Use floetrol paint conditioner for better flow and leveling of latex paints over previously oil-painted surfaces.
Preparation is key, so follow these tips to get the best looking, long-lasting paint job over oil-based surfaces.
Common Questions about Painting Over Oil-Based Paints
Can you paint latex over oil-based paint without priming?
It is not recommended to paint directly over oil-based paints using latex paints without first priming. Primer creates a uniform surface for the latex paint to adhere to. Skipping primer risks poor bond, peeling, and potential reaction between the latex and oil-based coatings. Always use at least an oil-based primer before applying latex topcoats.
How long does oil-based primer need to dry before painting over?
Oil-based primers take longer to fully cure than latex primers. Typical dry times range from 6-24 hours before being able to paint over oil-based primer. Always follow the manufacturer’s recommendations for proper recoat windows. Painting too soon risks poor adhesion and lifting of the topcoats.
Should I sand before priming over oil-based paint?
Lightly sanding before priming will ensure a solid bond and smooth finish when painting over oil-based surfaces. It dulls and roughens slick, glossy areas so the primer adheres well. Use fine 120-220 grit sandpaper depending on the surface. Avoid over-sanding which can damage the existing paint adhesion.
How do you paint over stained oil-based paint?
For areas where stains bleed through oil-based paint, use a heavily pigmented stain-blocking primer or a latex primer/paint formulated to block stains before applying your finish coats. These primers contain resins that seal in tannins and other bleed-through stains. Oil-based alkyd primers also help block many stubborn stains.
What mistakes should I avoid when painting over oil-based paint?
Avoid using cheap paints and rollers, skipping proper prep work like sanding and cleaning, insufficient drying times between coats, applying latex directly over oil paints without primer, lack of ventilation while applying primers, as well as painting in non-ideal conditions. Careful surface prep and following best practices will ensure success.
Conclusion
Painting over oil-based finishes is made simple by following these fundamental steps – identifying the existing paint type, proper surface cleaning and sanding, applying a compatible primer, and using appropriate topcoat paints suited to the surface. With careful preparation to ensure good adhesion, along with high quality primer and paint, you can achieve lasting results painting over previous oil-based paints throughout your home. Use this comprehensive guide to prep, prime, and paint over challenging oil-based surfaces with confidence.