Skip to Content

How To Mix And Use Bondo Wood Filler

Wooden doors and windows can rot when exposed to different weather conditions. Constant use of wooden furniture leaves damage on the surface. How do you repair or restore wooden items?  Can you use Bondo Wood Filler, and how do you mix it? Well, we found the answer for you. 

Disclosure: We may get commissions for purchases made through links in this post.

Mix the Bondo Wood Filler with a cream hardener. After mixing, these are the steps on how to use it for wood repair:

  1. Clean the surface
  2. Apply wood filler
  3. Smoothen the surface
  4. Paint or stain the wood

If this is your first time with such a DIY project, we are here to help you. So let's get started discussing Bondo Wood Filler and how to use it in more detail.

wood filler and brush on top of a working table. How To Mix And Use Bondo Wood Filler

What Is Bondo Wood Filler

Bondo Wood Filler is a durable mixture that can be used to repair the damaged parts of a wooden window, door, floor, furniture, or other wooden surfaces. It does not shrink, making it suitable for interior and exterior use.

Finishing a wood repair project with the use of a Bondo Wood Filler is quick. It adheres to the surface right away. Also, the waiting time for it to dry is short.  

Check this Bondo Wood Filler on Amazon

How To Mix Bondo Wood Filler

Bondo Wood Filler comes in two parts: the filler and the cream hardener. Mix the wood filler and hardener on a clean non-porous surface.

A good mix would be 1 part hardener with 3 parts filler. Mix this thoroughly to get a uniform color. Quickly mix the two components, as it hardens within 5-7 minutes of mixing. This means that you need to work fast on the application as well. 

How To Use  Bondo Wood Filler

A DIY wood repair with B0ndo Wooed Filler will only take 30 minutes. Here are the steps to filler application: 

1. Clean the Surface

The wood has to be prepared for repair. Remove any rotten or loose part of the wood with a screwdriver or hammer and chisel. Smooth the area with sandpaper to ensure the filler will adhere to the surface.

Clean the surface to remove dust and oil. Use warm water mixed with dishwashing soap. Alternatively, a surface cleaner can be used. A clean cloth should be dipped or sprayed on with either cleaning material. Then rub around the area so it is spotless.  Allow it to dry before proceeding to the next step.

Check out this all-purpose cleaner on Amazon

2. Apply Wood Filler

Spread the mixed wood filler with a putty or paint spreader. Apply the wood filler to the hole or gap generously until it is flat on the surface. You should not leave a thick coating of it on the surface, as it will be hard to sand. 

Also, use pressure so the mixture will adhere to the surface properly. Allow the filler to dry before smoothing the surface to avoid lumps or rough texture. 

3. Smooth the Surface

Sand the wood once the wood filler is completely dry. Use sandpaper to achieve a smooth surface.  100-grit sandpaper is good to remove the uneven application of the filler as well as smoothen rough edges. 

In between sanding, clean the surface with a soft-bristled brush or clean cloth. This will help in checking if the wood is level and avoid over-sanding. Also, cleaning the surface will make finishing easy. 

Check out this 24 pcs sandpaper variety pack on Amazon 

4. Paint or Stain the Wood

Bondo Wood Filler is stainable and paintable. This makes it easy to finish the area according to the color of the wood.  The repaired area will be unnoticeable and will have a more cohesive look.

Prime the surface before finishing the wood. This will help the filler to absorb the stain or paint evenly. Non-primed wood will absorb the paint more. The repaired area will be darker and more visible. 

For staining, apply on a small area first to see how much it will absorb. This is to avoid over-staining and an uneven look of the wood. 

Check out this water-based wood stain on Amazon

Here is a video tutorial to give you a better idea of wood filler mixing and application:

Bondo Wood Filler Tips

Bondo Wood Filler fixes non-structural damage in wood. It hardens but does not give structural integrity to the wood. However, it fixes the wood to make it look new again. We have some tips on how to use this wood filler successfully.

Safety Precautions

Make sure to follow safety precautions when using this wood filler. It has a strong chemical smell, so a face mask is a must. If working indoors, open the windows to make the area well ventilated. 

Since it bonds to itself, protect your hands by using rubber gloves.  Do not use your hands when mixing and applying, as this material will stick. Use a plastic spoon or wood spreader.

Prepare the Wood

The mixture will not adhere to damp wood. You can use a blow dryer to speed up the drying time of the wood before repair. 

Another option is to use a wood hardener, especially for wooden surfaces damaged by water. The liquid sealant penetrates the wood and stops further decay. Since the wood will not retain moisture, it will be a good base for wood filler. 

Check out this wood restore liquid hardener on Amazon

Use Small Quantity

Bondo Wood Filler dries quickly. This makes the repair work faster. Mixing a big amount of filler with the hardener will still dry fast. It is advisable to mix in small quantities. This will allow you to take your time in spreading the filler. Smaller quantities prevent wastage too.

Colored Hardener

When mixing Bondo Wood Filler with a hardener, you may opt to choose a different color instead of white. The wood filler comes with a small tube of white cream hardener. Bondo Creme Hardener also comes in red and blue colors. This is sold separately if more hardener is needed. 

Mixing the cream hardener well with the filler ensures it will harden upon application. Using a colored hardener will be a good indication if it is evenly distributed. There should not be any patches of red or blue. It will show too if you need more hardener.

Check out this red creme hardener on Amazon

What are the alternatives to wood filler?

There are other choices for filling in wood gaps. They may not be as durable as a wood filler.  However, they can be used to make small wood repairs such as nail holes and wood joints. 

Caulk

Caulking is a durable sealant that is used to fill gaps and cracks. This sealant gives protection from water damage because it is waterproof. It comes in different colors, so it is easy to match the wood finish.

Since it is easy to use, it still is a popular choice especially to fix wood edges and corners. The problem with caulk is it shrinks over time. It hardens after application but won't have a flat finish. It can't be smoothed with sandpaper.

Cleaning of the wood area has to be done too. You will need to put the caulk in a caulking gun for application. Once you do that, point the nozzle and fill the hole to the surface. 

Check out this waterproof caulk and seal on Amazon

Wood putty 

Wood putty can also be used to fill the gaps in the wood. It can be used to fill the joints on wooden walls and baseboards. Nail holes and minor blemishes can be repaired with wood putty.

It is made of an oil-based and plastic chemical mixture. Unlike wood fillers, this mixture will not harden when used to cover holes. So as the wood contracts and expands, it will also adjust. It is ideal for exterior uses.

The wood putty can only be applied after the wood is finished. Its chemical content can damage the wood. It is easy to blend with the wood surface because it comes in different wood colors.

Check this cherry wood putty on Amazon

DIY wood filler alternative

Wood glue and sawdust are DIY alternatives for filling in small gaps. Wood glue is readily available. Mix this with sawdust. Choose the sawdust that is close to the wood color of the item being repaired. Spread this on the gap and let it dry. Once dry, this can be sanded to have a smooth surface. 

To Wrap Things Up

Bondo Wood Filler is suitable for wood repair. It comes in two parts: the filler and the cream hardener. It is easy to mix and use for your next wood repair project.

Check out these related articles before you go:

How To Repair And Smooth A Splintered Wood Deck

How To Repair Spider Cracks In Cultured Marble Sink