One of my biggest things is YMMV (your mileage may vary), so while this is ONE way to prep, it’s not the end all be all! Some of you out there prep amazingly well, and never have issues, so this post is more for the beginners, who don’t really know all that goes into prepping a piece for the best foundation. So many people don’t prep at all. THAT is totally fine if you’re doing a piece for yourself and don’t care if your finish fails. BUT if you’re doing work for customers, you really want your finish to stand the test of time. In the end, all we really have is our reputation. One failed finish will be more remembered than the beauty of all of your other pieces.
The very first thing I do when I get a piece (after removing hardware if appropriate) is scrub it down really well, if I’m not stripping the existing finish off. I tend to get migraines from strong smelling or overly chemically (is that a word?) things. So my go to for cleaning furniture is something like Simple Green or Krud Kutter, but a 50/50 mix of vinegar and water works well too. These clean the piece and help to remove any build up of oils, etc. Other things that are great to use are Dixie Belle White Lightning (TSP hybrid), Fusion TSP (not really TSP) or real TSP (harsh). IF you will be using any shellac based product for bleed through or smells, do NOT use any product with TSP. TSP and shellac react on a chemical level and can cause adhesion problems.
I seriously clean a piece over and over until my rags or shop towels aren’t nasty anymore, using a green scrubby is a great way to get buildup off. I then use clean water to give it a good rinse. I let it dry really well. Then I inspect my piece, looking for areas that may need repair, or have gunk stuck on them.
Some people may ask me why I clean it so well if I’m going to sand it anyway. My answer is simple… I don’t like my sandpaper getting gunked up quickly. It’s more time consuming to have to keep changing my paper, and costs more money as well. Also, the friction of sanding can force any grime and oils into the grain of the wood, and can lead to adhesion issues later. ALWAYS sand a clean piece!
After I’ve inspected my piece (and it’s clean), I get to any repairs that may be needed. Filling gouges, missing veneer, gluing, whatever.. I take care of it now. Once all of the repairs are done, I sand. Now if I’m staining the piece, of course I sand it all the way down (or strip it). If I’m painting it, I make the decision based on the condition of the existing finish. If it’s a well done finish (no chips, runs, drips, smooth, etc.) I will just do a scuff sand with a higher grit sandpaper (120-220). This is done to give the paint some tooth to grab onto. After I’ve done my sanding (to whatever degree), I then clean the piece again. This cleaning isn’t as intensive as the initial cleaning, as you’re just getting off all of your sanding dust, etc. Usually for me, a good rinsing is all it needs. I let it dry and then go over it quickly with a damp cloth to make sure all the dust is gone. Now your piece is ready to become beautiful!
Keep in mind, different techniques or different substrates call for a different cleaning regimen. This is just for the standard everyday piece of furniture you may be refurbishing. Once again, this is not the law of the land, only a suggestion for an amazing foundation, because YOUR finish is only as good as the foundation you put it on!