Can you screw into wood filler? Technically, it’s possible, but you have to use the right filler and drill the screw the right way. This is to prevent cracking, crumbling, and poor bond between the screw and the filler material.
It’s quite inevitable that even the most expensive furniture will get damaged. When it cracks or chips, wood fillers are a handy solution. However, the challenge here is drilling into the wood filler to install screws and other similar hardware.
Types of wood fillers
To know whether you can screw on wood filler or not, you should first know that type you’re working on. Here are the three most common options used by woodworkers:
Simple wood filler
This wood filler is a mixture of carpenter’s paint and sawdust. The sawdust is made from the same wood type you’re working on. It could also be made of limestone, linseed, or chalk.
Most of these simple wood fillers aren’t as durable as other types. As a result, drilling a screw into this filler may not yield the best result. The screw won’t hold that well, especially if the material will be subjected to intense wear and tear. Overall, it’s not possible to drill a screw into a simple wood filler.
Exterior wood fillers
This filler is waterproof and is made to withstand wear and tear. It also holds polishes and stains well. You can also drill screws into this type of wood filler, thanks to its durable nature. It’s best used on wood that will be installed outdoors.
Two-part wood fillers
This wood filler is called two-part because of the process it takes during application. It requires an undercoat before the application of the second coat to let the filler set. Once dry, two-part wood fillers will be resistant to shrinkage and expansion. You can also screw into this type of wood filler without any problem.
Multi-purpose wood fillers
These wood filler products possess some of the characteristics of exterior and two-part epoxy types. You can use it on wood installed outdoors, and it also possesses the quick-drying nature of two-part wood fillers.
Moreover, multi-purpose wood fillers are the best to use if you’re going to drill and install a screw. It can also hold nails well.
How to screw into wood fillers
As long as you’re using the right wood filler, drilling a screw into it wouldn’t be a problem. Just make sure that you follow these steps:
Step 1. Sand the wood material first
First, you need to prepare the wood you’re using before filling it with a filler. You have to sand the rough edges and dirt so that the wood filler will adhere better.
Step 2. Apply your choice of wood filler
Once the wood is smooth, you can now apply the wood filler. Start applying at the edges using a knife, then work your way through the entire area. If your choice of filler tends to shrink, you can overfill the wood a little bit.
After that, you should let the filler dry fully before drilling a screw into it. This can take a few hours to a whole day, depending on the instructions included in the container.
Remember, you should let the wood filler dry first. Otherwise, the screw will not be fixed in position, and you’ll just ruin the filler. When this happens, you’ll have to redo the process and risk damaging the wood itself.
Step 3. Sand the dried filler
Once the wood filler is fully dry, you need to sand the top. You just have to sand it lightly for a smooth finish, especially if you’re planning to apply a stain or paint on it.
Step 4. Test with a small drill bit
Next, you should use a drill bit smaller than the screw you’re planning to use. This is to test whether the wood filler will drill well and create a defined hole for the screw.
If the wood filler cracks or crumbles on a small drill bit, it will crack more once you use a bigger bit.
Step 5. Make a pilot hole
A pilot hole will guide the screw into the filler while reducing wedging. The rule of thumb is that the pilot hole must be a bit smaller than the screw in terms of diameter. This is to leave enough material for the screw to grip as you drill it into the filler. Also, the pilot hole will prevent cracking or splitting the filler.
Step 6. Drill right through it
Once you have a pilot hole in place, you can drive the screw into it. The screw should go in smoothly and with a tight grip. I suggest fiddling the screw head with your finger to see if it’s moving or the surrounding wood filler has cracks.
If the wood filler cracks, it may not be suitable for drilling, or it hasn’t dried fully yet. I suggest testing this process on a spare piece of wood first if you haven’t tried this before.
Is wood filler as strong as wood?
Wood fillers can be as hard and strong as actual wood if applied and dried well. However, you should also know that this same characteristic will make wood fillers difficult to sand in case there are rough edges.
You should choose a wood filler suitable for the purpose you need. There are compound wood fillers as well as latex wood fillers that harden like wood. It’s a great choice for all-around purposes as well as drilling a screw.
What is the difference between wood putty and wood filler?
Many beginner woodworkers often mistake wood putty and wood fillers from each other. However, the two differ in terms of consistency.
Wood putty is made of oil-based compounds combined with plastic chemicals. It also comes in various colors to match the stain of the wood you’re working on.
On the other hand, wood fillers are made of real wood fibers and particles together with a binding agent. Unlike wood putty, fillers only come in a single color, so you’ll need to stain or paint it to match your wood piece.
Lastly, wood fillers are used to repair wood from the inside, while the putty is used only on the outside. This is because wood putty has chemicals that could damage the inside of wood materials.
Is Bondo strong enough to hold a screw in it?
Yes, Bondo fillers are strong enough to hold screws drilled into it. However, it’s not as durable as its epoxy counterpart. But to be fair, Bondo wood fillers can be sanded, painted, and stained.
In addition, you should know that Bondo wood fillers may not have enough structural strength if you’re subjecting them to extreme wear and tear. While it can hold a screw, it doesn’t guarantee utmost reliability under stress.
Can you screw into the patching compound?
Like wood fillers, patching compounds are made to fill cracks, grooves, and damaged areas on wood. It can either be mortar or cement-based, both of which are suitable for driving screws. However, you must press the compound to make it as compact as possible.
Aside from that, you need to use a small drill bit to prevent cracking. It will also stop the screw from walking or shifting out of position while being driven into the dry patching compound.
How do fix a screw that won’t tighten on wood?
A screw that won’t tighten on wood is a common problem. The likes of particle boards and plywood don’t hold screws very well. Still, there’s a workaround for this dilemma.
First, you need to drill a screw hole enough to fit a piece of dowel inside. You should use a bit that matches the dowel diameter you’re using.
Once you’ve drilled a hole, apply a lot of glue on the dowel and press it into the screw hole using a hammer. It should be snug and tight; otherwise, you’ve drilled a hole that’s too large.
Let the glue dry, then drill a new pilot hole for the screw right into the dowel. Lastly, drill your screw into it, and you’ll have a tight grip. Just make sure that the screw thread isn’t damaged in the first place.
Conclusion
Can you screw into wood filler? Technically, yes, but you have to choose a wood filler suitable for the task. You must avoid simple wood fillers as these don’t hold screws well. Also, you should let the wood filler dry first before drilling into it. This way, the material won’t crack, and the screw will be less likely to shift position.
