Most woodworkers have both wood filler and wood glue in their cabinets. The key is knowing the right use for each one, and that takes some failed experiments and woodworking gone wrong to know.
Luckily for you, you don’t have to go through that because I’ll tell you everything you need to know about the matter. Here’s a comparison of wood filler vs wood glue to let you know the purpose of each.
What Is Wood Filler?
Wood filler is a putty made of a blend of artificial materials and wood binders. These include clay, epoxy, polyurethane, and lacquer. Woodworkers use such materials to repair the wood or level its surface before painting. Most filler types can’t be used outdoors because they tend to crack under the sun.
As with any putty, wood fillers crack when they’re outside due to the surrounding conditions. They may also shrink as a reaction to the cold. So, they’re mostly used for indoor applications except if they’re solvent-based.
When woodworkers use wood fillers, they must level the wood first and make sure there aren’t any particles on the surface. Most of the time, they need to use sandpaper for that purpose. Only then can they apply the filler into the ruined areas and scrape the excess.
There are two types of wood fillers: solvent-based ones and water-based ones.
Solvent-Based Wood Fillers
Solvent-based wood fillers can work with virtually any type of wood and any kind of damage. Plus, they have leverage over water-based fillers because they can handle the outside weather without cracking, so people use them for indoor and outdoor applications alike.
These fillers will need the woodworker to apply a finish after application, though, to preserve the wood’s shape.
Water-Based Wood Fillers
Water-based wood fillers react to weather conditions and sunlight, making them only suitable for indoor applications. They’re also not recommended for regions with high traffic because of their low resilience.
These fillers need to be applied after staining.
What Is Wood Glue?
Do you need an adhesive material to stick two wood blocks together? Wood glue is your go-to. Woodworkers mostly use it when they want to bond a couple of pieces together without using nails.
Of course, wood glue is easier to use than nails, and anyone can use it even if they don’t have enough experience. Having the chance to stick wood without lifting a hammer is something a lot of people would pay for.
Glue is also convenient because you don’t need to paint over it. For example, you may need paint or finish to hide the marks when using nails, but that’s not the case with glue.
You can use wood glue for many applications, including bonding wood pieces, joining wood joints, and covering any cracks on the surface. Unlike wood filler, you can use it outdoors because it doesn’t react to the surrounding conditions.
The only downside to wood glue is the claims about its safety. Some brands are toxic, so you’ll want to make sure you’re working in a well-ventilated area. Otherwise, you may be subject to dangerous fumes.
The glue should also be kept somewhere safe and away from any potential flame. If the weather is too hot in the room you’re working in, you’ll need any kind of weather-resistant cover to maintain the glue’s integrity.
Wood Filler vs Wood Glue – The Major Differences
Wood filler and wood glue mostly have different purposes, except for a few cases where they can be used for the same application. There are many differences between them in terms of composition, uses, and properties. Here are all the major ones.
General Properties
Wood filler is made of a variety of synthetic materials, fibers, and sawdust. Meanwhile, wood glue is mostly made from epoxy or other adhesive materials. You can use wood glue both outdoors and indoors, while most wood fillers are only suitable for indoor use.
Wood filler doesn’t have a strong smell, so no need to wear a mask while using it. Meanwhile, glue can have a robust scent, and it emits harmful fumes, so you’ll need to wear a mask.
Requirements
When using wood glue or wood filler, there are some requirements you need to abide by. For example, wood glue needs a mask and a well-ventilated room for safety purposes. Meanwhile, wood filler requires you to seal it after you finish to preserve it and keep the wood intact.
Wood glue doesn’t need a seal because it’s adhesive by nature.
Lastly, wood glue requires a cool temperature, unlike wood filler, which you can use under any conditions. You may need to get a cover for the glue if you want to use it in high temperatures or hot rooms.
Outdoor or Indoor Application
If you’re using wood filler, you may want to consider the type you’re using first according to where you want to use it. You can use solvent-based types indoors or outdoors; they don’t react to the weather elements.
I can’t say the same about water-based types, though, which can only be used indoors. If you use them outdoors, they may get too dry and eventually crack because they don’t expand.
As for wood glue, you can use it anywhere you prefer as long as the temperature is cool enough for it. It expands with the wood, so it won’t cause any issues.
Drying Speed and Waterproofing
Wood fillers dry too fast for their own good. Once you apply them, they’ll dry shortly after. I can’t say the same about wood glue, which takes its time to dry. In some cases, you won’t be able to use your wood for days until the glue completely dries.
Moreover, wood fillers aren’t waterproof, while wood glue is.
To Wrap Up
Now that you know the major differences between wood filler and wood glue, I trust you can decide which one to use for your application. Remember the safety precautions when using wood glue, and use solvent-based filler if you’re working on an outdoor application.