How to Fill Wood

Boards from the lumberyard rarely are perfect.

So if you want a smooth surface for your woodworking project, you will need to fill the imperfections in the wood with a wood filler. Another use for wood filler is covering nail holes in walls when you change your décor.

Test the filler on a piece of scrap wood to experiment with stain or paint so you can match surrounding wood. You can avoid any unpleasant surprises this way.

Decide whether you need to fill the wood with a hardening or non-hardening compound. Non-hardening compound, called wood putty or plastic wood, often is used for imperfections and nail holes. Hardening compound, called wood filler, is used for deep holes and knots.

Fill the wood with your chosen compound. With nail holes, a finger can do the job. With larger holes, a putty knife will give you a smoother surface and less sanding work later.

Apply your finish immediately if using wood putty or plastic wood.

Wait overnight if you're using wood filler, because it needs time to dry before it will take a coat of paint properly. .

Sand the wood filler and apply your chosen finish or paint.

Things You Will Need

  • Wood putty, plastic wood or wood filler
  • Putty knife
  • Sandpaper
  • Paint or stain


  • Non-hardening compounds such as wood putty or plastic wood easily take a stain.
  • Hardening compounds, called wood filler, are easier to paint.
  • Check the label on the compound to be sure that it can be stained.
  • Gel stains are easier for beginners to use.


  • If you're using a solvent-based filler, ensure that you have good ventilation in the area.