sanding drywall

So.. you wanna know about sanding drywall?

Most people OVER SAND…

What does over sand mean?

It can mean one or more of several things…

  1. Use the right grit sand paper… many people use too coarse of a grit of sandpaper. Example: 80 grit sand paper would not be your best choice for normal pole sanding of everything. (although you could use it to sand green mud on the angles before your finish coat)
    1. Orbital sander may need 240 grit. Experiment to find your sweet spot. Too low of a grit, may chew up too much of your good mud. I know it sucks to change the sand paper more often but choose the lesser of the evils.
    2. You can get by with 100 grit for most pole sanders, some prefer to go with 150 grit, pick your poison.
      1. The problem with too low of a grit can lead to raising of the fibers/hairs of the paper of the wallboard.
    3. If you do raise the fibers, don’t worry, it’s not the end of the world crashing down on you… But you will need to lay them back down. How do you do that?
      1. You can mop or sponge with water will do the trick. Rinse as the dust stops coming off. A 5 gallon bucket works well for holding the water.
      2. You can prime. My choice is to use a paint sprayer (unless you are doing a remodel, then you may wanna brush n’ roll so you don’t ruin the carpet or maybe turn the pressure down on the paint sprayer when you are spraying by the carpet)
  2. Too many swipes of the paper – obviously repetition where you over do it, could lead to raising of the fibers
  3. Too much pushing/force behind the sander. You will need to push harder as your sand papers wears/loses it’s grit. So at first you wanna gently let the grit do the work & then as the grit gradually wears away, put more pressure on your pole sander/sponge sander.
  4. Some people choose to touch up with mud, instead of using the sponge sander (sander block). This is not my favorite trick, but I could see doing it where you are going for the smooth texture as there is less chance of raising the fibers and seeing problems come through the finish paint.
  5. The joints that tend to be the most visible are the flats (if you are striving for a lemon peel). So you could skim the flats with say a 14″ trowel and therefore eliminating most or all of the sanding of the flats and also eliminating ridges, lap marks, etc.
  6. You can wet sand. What is this? It is where you dunk your sponge/sander sponge in water. Again, when the sponge needs more moisture, give it a dunk in your 5 gallon bucket. (this is usually done when you need to keep the dust down) You may need to skim coat your ridges/edges as you can’t have thick ones for this to work.
  7. Lighting is also a factor. You will need ample light in order to see good enough to sand. Of course there are variables
    1. Are you doing new construction or are you working on a remodel where your are mudding into existing texture. Sanding into existing texture you will need the light closer to your work.
    2. Often for new construction if you set the 500 watt halogen light on the floor land angle it slightly so as you can shine it down the wall (up to say 14 feet). Is usually good enough.
      1. You will want to keep the glass on the halogen scraped clean (use a puddy knife or 3 in 1 paint scraper to scrape it off if it’s dirty.)
      2. You can hang a 300 watt light bulb from the ceiling to light up a whole room. (hang it from the wires of where the light fixture will be)
    3. If you’re on stilts you can use a sander pole to drag the light around.
    4. You can use an Orbital Sander to reduce dust in the air, on the wall and through out the house. It also takes a lot of the bull work out of it.
  8. The round pole sanders work best between coats of mud. The rectangular pole sanders work best for angles. The orbital sander works best for final sanding (of the finish coat).
    1. If spraying knockdown texture on ceilings and orange peel on walls, I like to use pole sander to buzz off the over spray that is on walls.
  9. You don’t need an orbital sander but you may be faster with one.