Paint doesn’t adhere to silicone caulking well. But, that doesn't mean adhering paint to silicone is impossible. If you’ve already used silicone-based caulking in an area you’d like to paint, there are a few things you can do to make the paint adhere better.
Step 1 – Sand the Caulking
Because paint won’t easily stick to silicone, you must first roughen up the silicone surface with heavy-grit sandpaper. Make sure you don’t pull all the silicone up or off; just make the surface rough.
Step 2 – Apply Spackling Compound
Paint will easily stick to spackling compound. Apply a thin layer of spackling compound over the roughed-up silicone. If you don't have spackling compound on hand, consider making a homemade spackle. Then, apply the spackle with a putty knife. Allow the compound to dry completely.
Step 3 – Paint Over the Silicone
Once the spackle has completely dried, you can paint over the silicone. Use an oil-based paint for the best results. Eventually, the paint will peel from the silicone, but it should last 3-5 years. Take your time while painting. Paint in short sweeping motions with a small paintbrush, so that you can see your work as you go and catch any areas you may need to sand and spackle again.