Wood Filler vs. Bondo (How To Use Bondo Body Filler On Wood)

The term wood filler is always used interchangeably with the word “wood putty”, although professional woodworkers made it known that there are key differences between both. Wood filler is a product widely used among woodworkers to ensure that their wood surface is smooth and free from holes.

These holes may be a small gap in the wood grain, and thus the need for a wood filler to make sure the finishing process of your wood is smooth together with the absorption of the finish and sealant. You can actually choose wood filler vs. bondo as they are both used in concealing the head of the nails used for finishing in woodwork.

Wood fillers generally contain pulverized wood byproducts – like sawdust suspended in some kind of binder that dries rock hard. Wood fillers are for different purposes: to smoothen wood grain, fill holes, and repair furniture.


Different Types of Wood Filler

There are several kinds of wood filler that can assist you in filling out cracks and holes in your wood surface. They may be water-based or solvent-based fillers.

  1. Water-based wood fillers

Water-based wood fillers are composed of organic substances like wood fiber, minerals, and cellulose. They get dissolved in water quickly and thus, are very effective for wood projects that require a thinner wood filler. So, regard them as a top priority when you compare them with a solvent-based wood filler.

They also get dry easily in about 15 minutes which makes the whole process fast and simple. Besides, they contain lower amounts of volatile organic compounds (VOCs) which enables them to release less odor when working with them.

  1. Latex-based wood fillers

Latex-based wood fillers are categorized under solvent-based wood fillers and are used for filling gaps and dents in wooden floors, cabinets, and furniture. They are available in various colors in the market, which makes it easy to use a wood filler that is compatible with a particular wood shade.

To use this product, you will need to work with a putty knife. After applying and leaving it dry, you need to sand the filler to smoothen it out. However, latex-based wood filers have a disadvantage as their structural strength is little. So, you need to avoid using a nail or screw in the applied spot not to make it crack again.

  1. Epoxy wood fillers

When choosing a wood filer with a high structural strength to fill wider gaps or cracks, epoxy wood fillers are the one to go for. It is available in two package versions, either as a can or tube that has a colored or clear option based on what you need.

Unlike the other fillers, sanding is not feasible once the product is dry so careful application is very important. They become stronger than the wood itself once dry, so you can safely use a nail or screw on it. However, we recommend you use them only in hidden areas due to their plastic-like appearance.

Wood Filler vs. Bondo

What is Bondo body filler?

Bondo body filler is a polyester resin filler product that initially originated in America for automotive body repair. Although Bondo was originally made for auto body repair, it contains typical properties ideal for wood repair. This product is cheaper compared to other wood fillers, has strong adhesion force, and gets dry quickly.

As much as wood filler vs. Bondo are both used to conceal wood holes. Bondo Body Fillers are effective at fixing chipped furniture, scratched, cracked, or missing veer and edges. They are also used in filling hardware holes, repairing gouges, and several other woodworks.

Bondo body fillers are used to make permanent repairs to both indoor and outdoor furniture. The product is known for its durability.


How to use Bondo Body Filler

Materials Needed : 

Before working with this product, you will need to prepare the wood surface. Make use of 220grit sandpaper to sand the surface, it will help with adhesion. Avoid scraping off excess material since it will increase the amount of layer you need to apply. Then, blow off the sawdust and wipe the surface clean.

Measure the area that needs to be fixed, so you decide the amount of body filler needed. Then, mix the body filler well with a wood hardener before applying the filler to the affected area. Apply the filler to the area, allow it to dry, and then sand away the extra.

  1. Clean and get rid of old materials

Firstly, scrap out loose and weak materials from the wood furniture. You can use a hammer, chisel, or a small pry bar to get rid of loose materials. As earlier mentioned, avoid removing a lot of materials as this will only result in needing more products to be applied. Blow off the scraped materials and make sure there are no remains on the wood. When done, wipe the wood surface with a dampened cloth. All these preparations will help Bondo to adhere well. After blowing off the materials and cleaning, make sure the wood surface is left to dry.

2. Apply the body filler

After ensuring that the wood surface is dry, the bondo body filler is ready to be applied. Apply it with the use of a putty knife and ensure to apply with pressure on the affected area, this will aid optimum adhesion. How deep the hole on your wood surface determines how much Bondo body filler is required.

After application, scrape off excess resin to reduce the effort required during the sanding stage. Be quick with your work since Bondo dries quickly.

3. Prepare the wood surface

Now, sand out the wood surface until it appears bare. Measure the surface that needs fixing as this will help in deciding the amount of Bondo required. If the gap is too wide, fill it using a piece of wood. Wipe the surface clean after.

4. Mix Bondo body filler

Wear your safety mask and goggles before you start working especially if you have respiratory diseases. Since Bondo dries quickly, start by mixing a small amount. Knead the hardener before squeezing it out over the putty. Use a stick to mix thoroughly until the resin is uniform. Depending on the type of hardener used, the final color you get is either pink or grey.

5. Sand Bondo body filler

Rough and medium sandpapers are needed at this stage. Finesse your edges until you get what you want. Start with the medium sandpaper to smooth the surface and then end it with the rough sandpaper. Sand until the filler and the surface level is the same.

Also Read: Top 5 Best Sealer for Outdoor wood furniture

How to use Wood Filler

  1. Mix the wood filler

Start by mixing the wood filler in its container using a putty knife. Mix until the paste is smooth with a uniform color and texture.

2. Apply the wood filler

Solvent-based wood fillers harden faster compared to water-based wood fillers, so you will need to work faster. Apply pressure when applying the filler into the crack. Remove excess while making sure not to gouge the putty knife into the fixed area.

3. Smoothen the surface with your fingers

Apply more pressure and press the wood filler into the crack with your fingers, and remove excess from the wood. To get rid of wood filler from your fingers, wipe it with a dry cloth or towel. In case of leftover, rinse with water (water-based variety) or mineral spirits (solvent-based variety). Clean your putty knife with a rag and water or mineral spirits.

4. Sand the wood filler

Allow the wood filler to sit for about 30 minutes or more so it can harden, or probably leave it for an hour. If your wood filers turn out very hard, make use of an oscillating sander, starting with medium-grit sandpaper followed by 220-grit sandpaper. Rub the sandpaper at the filled area in the same direction as the wood grain.

5. Wipe the surface with a tack cloth

If there is sanding dust left on the surface, it can lead to some difficulties during the staining or finishing process. The liquid will mix with dust and generate a lumpy grainy surface, definitely what you don’t want. To avoid this, use a tack cloth to remove dust without creating more mess. Making use of water to clean will lead to nothing but a total mess.

6. Finish the wood

Finally, the filled area is ready for staining and finishing. Staining will help to match the color of the filler and the wood but do not expect the filler to be totally invisible.

Wood Filler vs. Bondo

Conclusion: Wood Filler vs. Bondo 

For every woodworker, they would have had cases where they need to work with either wood filler or Bondo body filler. If you are a beginner, be aware that the key to achieving a perfect woodwork project is to use the right type of wood filler.

In this article on wood filler vs. Bondo we have covered what wood filler and Bondo is. We have also talked about how to use both products correctly with the necessary materials required.