Even for those of us who’ve spent years mastering the art of woodworking, it’s not uncommon to discover exposed joints or nail holes in our final creations. Thankfully, addressing these imperfections is neither complex nor time-consuming when you have wood fillers at your disposal.
Now, if you’re pondering whether wood filler hardens enough to seal cracks or gaps effectively, you’re in the right place. In this guide, I will share my knowledge to ensure you have all the information you need.
Is It Possible To Harden Wood Filler Without a Hardener?
Without a hardener, wood fillers cannot possibly harden. By shielding the wooden surface from external factors like temperature, moisture, and humidity, the wood hardener assists the wood filler in strengthening the integrity of damaged wood.
However, even without a hardener, ambient oxygen can help the wood filler become more durable. The process can take two to three years to complete and the wood filler won’t dry even after it runs out, instead, it merely settles.
Wood Hardeners That Harden Wood Fillers Fast
Usually, wood filler hardens to a consistency that can be sanded. You should let the wood filler take at least 30 to 60 minutes to harden if you want outstanding results.
Here, we’ve included a list of some of the top wood hardeners that work well with wood filler to efficiently patch up wood cracks.
Minwax High-Performance Wood Hardener
Minwax, one of the most reputable companies on the market, developed a superior, high-performance wood hardener that functions in concert with wood filler. It quickly and thoroughly seeps into the wood because of its thin and watery character.
Bondo Rotted Wood Restorer
Bondo manufactures top-notch wood hardeners in addition to items to mend rusted cars. It provides a high degree of convenience, quality, and water resistance, positioning the brand as a premium choice.
LiquidWood is another wood hardener that works well with wood filler. It is essentially an absorbent epoxy that is graded for structural repairs to bring back the strength of any piece of wood.
The following list of wood hardeners, on the other hand, does not work with the majority of wood fillers.
J-B Weld Original Liquid Hardener
This wood hardener works effectively without requiring the addition of wood filler. Its appearance is milky and watery, which facilitates easy and quick absorption into deteriorated wood.
Additionally, the rapid absorption of the hardener ensures efficient and reliable results for your wood restoration projects.
PC Petrifier Wood Hardener
PC Petrifier Wood Hardener can be used as an outdoor primer in addition to its function as a wood hardener. It has a thick consistency, which makes it much simpler to brush over hard surfaces and somewhat less absorbent.
Typical Duration For Wood Filler To Harden
The typical time it takes for the wood filler to harden is between 30 and 60 minutes. However, some wood filler does harden quickly based on their type, brand, and base.
An excellent reminder for all woodworkers, especially beginners, is to add wood filler to damaged wood quickly. This prevents it from hardening before you finish applying layers, allowing you to spend more time sanding, painting, or refinishing your wood.
After examining several wood fillers for workability, quality, and adaptability, here are the top 10 wood fillers available in the market today.
Wood Filler Product
Rust-Oleum Varathane Fill Stick for Wood Repair
FamoWood Wood Filler
Gork’s Goodfilla Water-Based Wood & Grain Filler
3M Bondo Wood Filler
Aqua Coat Grain Filler
1 to 2 hours
DAP Plastic Wood All-Purpose Wood Filler
Minwax Color-Matched Wood Filler
2 to 6 hours
Elmer’s Carpenter’s Stainable Wood Filler
up to 8 hours
Elmer’s Carpenter’s Interior Wood Filler
12 to 24 hours
Coconix Floor and Furniture Repair Kit
up to 24 hours
Recommended Drying Time For Wood Fillers Before Painting And Sanding
The wood filler typically needs 2 to 6 hours to dry completely before you can sand and paint the wood. The kind of wood filler, and the size, depth, and temperature of the cracks, holes, and grooves are still important considerations.
Even though the best wood fillers dry in a matter of hours, it’s advisable waiting at least 24 hours before sanding and painting. Also, to achieve the best results, be sure to take into account the manufacturer’s specified estimated drying time.
However, wood fillers tend to dry so hard that they are difficult to sand. For a more realistic effect, experts recommend using an oscillating sander and sanding the filled area in the same pattern as the wood grain.
How To Make Wood Filler Dry Quickly
As for many woodworkers, the shorter it takes the wood filler to dry and harden, the better. Not only does it complete their project faster but also gives them more time to do other tasks.
Applying wood filler in warm weather is a terrific suggestion from professionals for getting it to dry fast. Summer is the best season to undertake your woodworking projects since they dry quickly.
Still, the drying time of wood fillers is one of the major errors made by woodworkers, which they either underestimate or overestimate.
There are steps you need to do to speed up the drying process of the wood filler in addition to according to the manufacturer’s guidelines for drying time. Here, we’ve provided 5 simple methods so you may select which wood filler does harden and dry most quickly.
Step #1: Clean the area
Cleaning the area of the wood you’ll be working on is the first and most crucial step you need to take. To make the wood clear and clean, remove any dust, stains, or paint and scrape away any splinters.
Once you’ve meticulously scrubbed and scraped the entire wooden piece, place it in a warm and dry spot, preferably under sunlight. This setting facilitates quicker drying, allowing you to transition to the subsequent step in your process smoothly.
Step #2: Combine Wood Filler And Hardener
The next step is to get the wood filler ready. On a piece of wood board, blend wood filler and hardener using a putty knife. The ingredients should be well blended after kneading them back and forth.
Also, it helps when you warm the wood filler first before the application method. Do this using a thermostat or heat gun to shorten the time it will take for the wood filler to dry and harden.
Step #3: Apply And Layer Wood Filler
After combining the wood filler and hardener, take a sizable portion of the mixture and spread it over the wood’s damaged area. To ensure that there is ample room for moisture to escape and speed up drying, apply thin coats of wood filler layer by layer.
Applying a little coating of wood filler at a time and waiting for it to cure and dry before adding further coats are key.
Step #4: Keep The Wood Warm
After applying many coats of wood filler to the board, the drying process must be completed by warming the wood for around 15 to 30 minutes. To hasten the wood filler’s hardening and drying, it’s advisable to expose the wood to sunshine.
You may also use a hair dryer or a fan to blow air into your woodworking area. This increases air circulation while decreasing humidity and the drying and hardening time of the wood filler.
Step #5: Sanding
Sanding can then be done once the wood has completely cured. The wood may now be stained or painted to give it a polished, tidy, and smooth appearance. Wear a dust mask while sanding the wood for your protection because wood may be damaging to your respiration.
Once you’ve finished sanding, dry the wood in the sun or with a hairdryer before applying a stain or paint to complete your woodworking projects.
Reasons Why Wood Fillers Tend to Crack
Wood fillers frequently break because they have not yet fully dried and set. Additionally, wood fillers may fracture as a result of temperature fluctuations  in the area when they contract or expand.
It’s recommended to maintain the wood in a warm, dry environment and wait until the wood surface is dried before applying another coat or moving on to the next phase.
Methods To Fix Cracked Wood FIllers
It’s crucial to know how deep or large the region you will be working on is and the quality of the wood is finished before you fill in those fractures. With this, you can choose where to start and how much wood filler to use.
Thankfully, there are two ways to repair cracked wood filler without further harming the wood.
- The first technique involves totally removing the old wood fillings and beginning anew. After that, apply a thin coating of wood filler in the proper quantity to the crack and allow it to cure.
- The second involves applying varnish to the wood fillers used to repair cracks. It is a simple and effective way to keep the fracture in place and conceal it.
Wood Hardener Alternatives
There are several alternatives to the conventional chemical-based wood hardeners that you might employ in your next woodworking projects. These substitutes for wood hardeners are durable, dependable, and, most importantly, successful in hardening wood.
The following are some of the greatest alternatives to wood hardeners.
Try acrylic resin if you are sensitive to wood hardeners made of chemicals. It is water-based, contains tough polymer emulsions, and is effective on wood.
In addition, acrylic resin is a popular choice among woodworkers because of its quick-drying capabilities, ease of production, powerful protection, and attractive decorating.
Despite being chemically based, epoxy resin is a fantastic substitute for wood hardeners since it strengthens fragile wood. The strength of the wood fiber will be more effectively embodied if the acrylic resin is poured into the drill hole.
Epoxy resin is waterproof, making it a great wood sealer for preserving the natural look of furniture, floors, and tabletops while preventing cracking, peeling, and rotting. But is epoxy resin food-safe? Let’s find out next.
To provide a barrier against entering moisture or water and harden and tighten your wood, utilize natural oils like linseed or Tung. Although it could be a simple and natural procedure, the curing process might take some time.
What’s nice about utilizing natural oils is that they act as a protective barrier that soaks in while leaving the natural texture and color of the wood alone.
Although using a pentacryl hardener may cost more, after the wood has dried, it cannot be easily broken. All that is required is to place a plastic bag over the wood, let the hardener soak, and then allow the wood to dry.
Furthermore, when exposed to varying degrees of temperature and humidity, pentacryl does not discolor, degrade, or oxidize the wood.
Polycryl Wood Fortifier
Lastly, a Polycryl wood fortifier is a wood hardener alternative that can harden the surface of the wood yet does not penetrate deeply into the wood fiber.
However, a generous amount of this wood hardener alternative can close the wood pores, provide a shiny surface, and prevent wood damage for a long time.
Does Wood Filler Get Hard Like The Wood?
Indeed, once wood filler has fully cured and dried, it attains a hardness comparable to wood itself. While numerous wood fillers on the market promise to dry and solidify within mere minutes, allow a window of 30 to 60 minutes to ensure optimal results.
Given its capacity to harden like wood, wood filler proves to be an outstanding option for repairing damage and restoring the integrity of your wooden items or structures.
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Wood fillers offer a wealth of knowledge yet to be uncovered, and in this post, let me demystify the notion, confirming that wood filler indeed hardens.
Moreover, integrating top-tier wood fillers and hardeners, paired with the application of proper techniques, paves the way for more effective and gratifying experiences in your future woodworking ventures!