Why would you ever want to make your own wood filler? At first glance, it seems to make no sense.
For a mere $5-$10, you can purchase a good, strong wood filler or putty in several basic tints. Some wood filler even includes tinting agents to change the color so that it is somewhat close to the color of the item you are patching.
The reason you want to do this yourself: "somewhat close" is not good enough.
You want the exact color, or at least as close as possible.
Where do you get the color of your wood? From the wood itself.
Often called "cabinetmaker's putty," this wood filler is made from fine wood dust mixed with a binding agent. It is a quick, convenient wood filler that closely matches your wood's color.
- Wood Dust: Take or make very fine wood dust--not sawdust and certainly not wood shavings--from the material you want to patch. Use edger or sander dust. Make sure that the dust is indicative of the area you want to patch. For example, you would not want to use dust from a knot, which is usually darker than the rest of the wood. Separate and discard large pieces of wood that may happen to get mixed in. Clean obvious impurities from the dust, such as metal shavings.
- Binding Agent (Glue): Most wood glues are lightly brown-tinted. If you can find white wood glue, you will have a better color match. The color of the glue will not influence the color of the putty.
- Latex Gloves: As long as you do not have a latex allergy, latex gloves will fit tighter on your fingers than nitrile or vinyl, making the mixing process easier.
- Mixing Surface: A disposable surface to mix the putty--a piece of clean wood, scrap of drywall, cardboard, foil, etc.
- Putty Knife: The knife that you will use for applying the putty is also used for mixing the putty.
- Gather Sawdust: Get a palm-sized portion of dust and place it on your mixing surface.
- Add Glue: Consistently add glue to the sawdust while mixing. If you are familiar with making cookies, the mix works much the same way. A majority will be dry, with glue slowly softening the mixture. Make sure that you do not use too much glue.
- Make the Dough: Form the mixture into a workable dough until it becomes a putty-like material that you can roll between your fingers.
- Apply: Push the putty into the gouge, scratch, or hole, removing as much excess material as possible. Work quickly.
- Clean: Glue-based wood filler is difficult to clean. So quickly wash off your putty knife.
- Sand: After putty has dried, sand very lightly with fine grit sandpaper. It will not take much effort to sand this putty; oversanding will only gouge your patch. Discard unused wood filler; it will not save.
Homemade wood filler is not perfect stuff. Because it is made only of glue and sawdust, it is not strong enough to bridge large gaps--small holes, cracks, and gouges.
Color will be close, but 100% accurate. As with any wood filler, you will not be able to match wood grain.
Finally, it is quite a mess to make, though the latex gloves and disposable mixing surface mitigate the mess.