Prepping Furniture For Paint or Stain
By now we have all heard there's "No Prepping, No Sanding, and No Priming" involved with chalk paint, but that's not the always the case. There are exceptions to every rule, even in chalk painting, and most of us have learned this the hard way. Prep doesn't have to be long necessarily, but it does need to be thorough if you want a smooth, even paint finish that actually sticks to the wood and doesn't peel off once you start waxing.
To sand or not to sand? I'm a firm believer in sanding. The picture above is of my vintage Ethan Allen trestle table. As you can see, it had a very slick finish that was damaged and a dark stain that's known to bleed through light colors. Right off the bat I knew there will be lots of prep work for this table. Since I was planning on applying a new stain to the top only, then the old varnish needed to be completely removed until I was down to bare wood.
For surfaces that aren't as glossy and slick as the table, you can do a quick scruff sanding on the areas you plan on painting. This will provide a smooth surface, but it will also help the paint adhere to the existing finish. For this little cabinet, I used a sanding sponge and it took me less than 5 minutes.
For bigger projects I use my electrical palm sander. Remember to wear a proper protective mask designed for paint projects since many old finishes are toxic when being removed. After you have finished sanding (scruff sanding or down to bare wood), run your hand over the piece to see if there's any old paint drips or rough places that you might have missed.
When I'm satisfied with my sanding job, I vacuum the entire surface using a brush attachment. Next, I wipe it down with Dawn dishwashing liquid and water and then I rinse it to remove any soapy residue. Once it's dried completely, I wipe down with a clean tack cloth to remove any remaining dust or lint. A quick scruff sanding, followed by vacuuming, wiping it down with Dawn and a tack cloth will only take about 5-10 minutes, but can save hours of having to re-do a project.
To prevent tannin bleed through when using a light colored paint (chalk paint, latex, etc), you will need to use a good primer specifically designed to prevent bleed through.
For more tips and specific products I use, check out http://www.thetatteredrabbit.com/how-to-prep-furniture-for-painting/