How to Paint Latex Paint over Oil-Based Paint
The seemingly simple task of applying a coat of paint over an existing one can get a little bit complicated if you are painting over an oil based paint with latex paint product. The two simply aren't compatible. Problems arise because the oil component of the base paint has a tendency to repel the latex paint. This can result in the cracking and pickling of the painted surface. However, the task can be done effectively if you prepare the surface that is oil painted beforehand to stop the bubbling and peeling occurring.
Step One – Cleaning the Area
First, make up a cleaning solution in a bucket. Fill the bucket with cool water and add a few squirts of washing up liquid. The mix should be soapy but not overflowing with suds. Clean all the surfaces that are to be painted by sponging them over. If the job is an exterior one, you may need to clean the area more thoroughly so use the wire brush on any stubborn areas where dirt or stains have built up.
Step Two – Rinse and Dry
Discard the dirty soapy water and refill your bucket with clean water. Rinse all areas until all residual soap and dirt has gone. Dry thoroughly with kitchen towel or dry cloths. Mask up any adjoining surfaces such as walls or frames that you do not want marked before you actually begin applying paint.
Step Three – Applying Oil Based Primer
An oil based primer will act as a barrier between the two incompatible types of paint and isolate them from each other. As with all oil based products, oil based primer has a tendency to separate in the can so before you open it, give it a really thorough shake.
Open the can; if there appears to be separation of the product, use your stirrer or a wooden spoon end to mix the contents together. Wipe the stirrer with kitchen towel. Paint the area with a thin layer of the oil based primer and allow this to dry thoroughly. When it is completely dry, apply a second coat.
Step Four- Applying Latex Paint
Latex paint also has a tendency to separate in the can so give it a good shake before opening. To be sure the product is well mixed, give it a stir with your stirrer. Now, you are ready to apply a layer of latex paint to your prepared surfaces. You will probably need to apply at least two coats to give a really durable finish. This will usually depend on the color of the paint. If the area is external, it’s a good idea to apply an additional layer to ensure the paintwork lasts for longer.
Step Five – Unmask the Newly Painted Area
Remove the masking tape. It’s best to remove this while the top coat is still slightly flexible. Leave the paint to dry too much and you may find the tape hardens and is difficult to remove. Hardened masking tape can peel away part of your paint finish when removed so act swiftly once the final coat has been applied.