how to mix Bondo wood filler?

Bondo is a great tool to have on hand. It’s an easy way to patch up holes in your walls, cabinets, and other surfaces and make them look new again. However, if you mix bondo too much with water, it will take forever to dry out and become hard as a rock again! The trick is adding just enough water so that the bondo can be easily mixed together into a smooth paste or putty-like substance. You don’t want it too wet though because then it will never dry properly—trust me on this one!

get out your Bondo (obviously)

Once you have all the supplies and your room is cleaned up, it’s time to get started! First, mix up the Bondo with a plastic spoon or putty knife until it’s roughly equivalent to peanut butter. You can also use a paintbrush for this step if you’d like; just be sure to thoroughly clean it afterward so no residual Bondo gets in your paintbrush jar. Once you’ve achieved the desired consistency, add in half of your water (you won’t need more than that). Then get out some sandpaper and start smoothing out any lumps or bumps while stirring constantly with a clean brush until they’re gone.

grab a cup of water

Before you begin mixing your Bondo, grab a cup of water. This is to be used as the solvent to which the filler will be added. The amount of water needed will depend on how much Bondo you’re using and how thick you want it to be. If you need more than one cup of solvent, use more containers filled with solvent rather than adding more water to one container.

To get started, add your Bondo powder in an even layer about 1/4″ thick onto a plate or other flat surface that won’t absorb any moisture from the Bondo (no wood). You should then pour some solvent onto the top of this layer until it forms what looks like a wet sandcastle wall:

pour some wood filler into the cup.

  • Using a cup that is big enough to mix the wood filler in but small enough that you can mix the wood filler with a putty knife, pour some wood filler into the cup.
  • Mix the product until it is well combined and smooth. This will take some time so set aside at least 20 minutes for this task when you begin working on your project, or do it over 2-3 days if necessary (for example one hour each day).
  • Now that you’ve learned how to mix Bondo wood filler properly, use these instructions as a guide to help you apply a layer of Bondo to your project!

add just enough water to the bondo to make it easy to mix.

  • Add just enough water to the bondo to make it easy to mix.
  • Wetting the Bondo is not required. In fact, adding too much water will prevent it from drying properly and can cause it to separate.

mix the Bondo and water together with a plastic spoon or putty knife.

  • Use a plastic spoon or putty knife to mix the Bondo and water together until it is no longer lumpy.
  • If you don’t have a plastic spoon or spatula, use a clean plastic knife.

when you have mixed it enough that it is no longer lumpy, apply it to whatever surface you are working on.

  • Mix it until it is smooth and not lumpy.
  • Don’t add too much water.
  • Don’t add too little water.
  • Don’t add too much Bondo.
  • Don’t add too little Bondo.

let it dry for 30 minutes

As soon as you’ve applied the bondo wood filler to your project, it’s important to allow it to dry for at least 30 minutes. This is because when bondo is still wet, it can leave stains on any surface that touches it. However, if you find that the bondo has dried sooner than this and still appears wet, simply wait another 30 minutes before continuing with the next steps of your project.

If you don’t have time for this waiting period or if the weather where you live is particularly warm and humid, there are some things that you can do to speed up the drying process:

  • Turn on a fan in order to help circulate air around your work area;
  • Use a hair dryer set on low heat (or no heat at all) and aim directly at areas where there are large drips; and/or
  • Wait until evening or night-time temperatures fall below 70 degrees Fahrenheit before working with your project

sand down any unevenness with a piece of sandpaper.

Now that your bondo is all smooth and sanded, it’s time to fill in the missing parts of your piece.

You can choose whatever color you want—I chose white because I wanted a light-colored wood filler to match the existing wood on my piece. You can also use a darker color if you want to make holes more obvious or add some contrast to your piece. If you decide to use multiple colors, just be careful not to mix them together before application!

To apply your wood filler, first, dip your finger into some paint thinner and rub it around the opening of each hole (this will help prevent clumps). Then apply small dabs of filler into each hole with an old toothbrush or disposable paintbrush (or something else that will allow for easy cleanup later).

wipe off all of the dust from the sanding.

Once you’ve completed the necessary sanding, it’s time to apply the bondo wood filler.

However, before you can do that, you need to remove all of the dust from your work area. This is important because if there’s any dust left behind when you’re applying the bondo, it could cause bubbles in your patch. There are several different ways that you can remove this dirt:

  • Use a damp rag or towel and wipe down your workspace with water and soap until it’s clean
  • Use a dry rag or towel for quick cleaning (this works best if you have access to power tools)
  • Vacuum up any remaining particles with a vacuum cleaner or shop vacuum
  • Broom up small bits of debris with a broom

if you want, paint over your project. if not, move on to your next project.

If you want to paint over your project, wait at least 24 hours. If you don’t want to paint over your project, or if it’s large and needs more than 24 hours of drying time, move on to another project.

Bondo is an awesome product, but make sure you don’t waste it by adding too much water when mixing!

Bondo is a great product to use for wood filler, but you don’t want to waste it by adding too much water when mixing. Adding too much water will make the bondo too thin and hard to sand down later. To avoid this, we recommend using either a plastic spoon or putty knife to mix your Bondo.


We hope that this article has been helpful to you. If you have any questions or need more information, please don’t hesitate to ask!

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Martin Flood

Martin Flood has been working in the construction industry for over 20 years as a general contractor with expertise in remodeling projects that are large or small. He has furthered his career by specializing in epoxy resin flooring, providing excellent service to both commercial and residential clients. Martin’s experience enables him to offer professional advice on how to choose the right type of project based on your needs and budget.

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