FURNITURE TIPS - Painting over an existing finish

To paint over an existing finish, there are a few things to consider. One is the overall condition of the original finish. Most factory finishes are done in lacquer and older finishes tend to lose their plasticity and get hairline cracks running through it. If this has happened to your piece or you have bare or worn spots, it may be worthwhile to go ahead and strip the old finish off. Otherwise the cracks will show up in the finished project.
If your finish looks sound, where you need to start is by removing all the hardware. Any parts that also come off may make the job easier.
Grab some naphtha or mineral spirits and some clean cloth rags, and wipe the whole piece down once or twice. This will remove any furniture polish or body oils that may still be present. If there is any organic matter left on it, you may have to use a damp rag to remove it before moving on to the next step.
In order to provide the new finish tooth to adhere to, you will need to do some sanding with 400 grit wet or dry sandpaper. sand it until you have removed all traces of the original sheen. To get into some nooks and crevasses, a general purpose Maroon scotch-brite pad works well. Once you are done with the sanding, give it a good blowing off with compressed air (Wear your particle mask) or vacuum up the dust followed with a damp rag.
With all the prep work done, give it a final wipe down with naphtha and let it dry for at least 30 minutes prior to applying your first coat of paint. Make sure you doing it in a dry dust free environment if you can. A tack rag is a very important finishing tool. Oil based finishes are going to be the most compatible to the lacquer, and hold up the best. They do require paint thinner for cleanup instead of water. Make sure you follow the instructions on the can.