Have you ever tried to drill into balsa wood and… failed?
Don’t worry, this is a struggle many model builders are familiar with as most model planes/ships are made with balsa wood. Drilling into balsa wood can be a little tricky and you’ll definitely encounter problems whether you use a manual or another handheld drill.
But why it’s hard to drill into balsa wood? Because of the low density, the wood is easier to carve a knife. The problem arises when you try to drill this soft, lightweight lumber.
So, how to drill holes in balsa wood then?
Use a brass tube in a drill bit and exert the right amount of pressure to prevent tearing out the wood. You can also use well-sharped spur drill bits or Forstner bits at high speed to avoid splintering. Using scrap wood platforms or gluing bother sides with papers are also great ways to ensure clean-cut holes.
Here, let’s look at the reasons why drilling balsa wood is hard and find out the ways to overcome them.
Why It Is Hard to Drill Holes in Balsa Wood?
Ever wondered why balsa wood is considered one of the most unique types of wood? Because it’s technically a hardwood, however balsa is still the softest and lightest wood. This contradictory nature and it is very little structural mass make balsa wood unique among all woods.
As balsa wood is incredibly light, flexible, and strong for its weight, it’s a popular choice for woodwork. But the timber doesn’t have much density at all and is filled with voids. Because of this, there is more air than wood fiber underneath the surface of the wood.
That’s why it’s so easy and takes only a little force to snap the balsa wood in two. No wonder you keep having problems running a drill into it.
Splitting Apart from Too Much Pressure
Drilling the balsa wood with a standard manual hand drill is not easy. If you put little pressure, it won’t create a hole. On the other hand, if you put too much pressure, the wood will end up splitting apart.
Tearing Around Holes
Predrilling a pilot hole and then making it bigger is a useful tactic while drilling. However, for balsa wood that’s not the case, unfortunately. It’s hard to stop the tearing from happening around the pilot hole.
Not Dense Enough for A Hard Wood
As mentioned earlier, balsa wood is one of the softest lumbers on the market. Despite being a hardwood, it has very little density. So, you can’t treat it similar to other hardwood. That means the standard drill doesn’t work well on balsa wood and puts too much pressure on it.
How Strong Is Balsa Wood?
So, you may think why balsa wood isn’t hard enough despite being a hardwood. And how do we know it isn’t strong like other wood?
For that, the Janka rating comes into play. The Janka Hardness Scale is a way to assess wood strength. It measures how much force does it take to dent a piece of wood.
Accordingly, balsa wood has a Janka rating of 70lbf only. So, that means a mere 70lbs of force is able to break through balsa wood with ease.
This may not seem much but by comparing the rating of other hardwood, you’d get the picture. For example, maple has a Janka rating of 1450lbs which is almost 20 times harder than balsa wood!
However, don’t get discouraged by the low Janka rating of balsa wood. Actually, it has an excellent weight-to-strength ratio.
The Janka rating reflects the compressional strength of the woods. Now you’re probably thinking what is compressional strength?
Compressional strength marks how well wood holds up before it collapses in on itself because of compressional stress. And shear strength tracks how well wood holds up when under shear stress.
Balsa wood can hold up on its own as it has great shear strength. However, while drilling balsa wood, the focus is more on compressional strength. That’s why you’ll face trouble while drilling balsa wood.
Ways to Drill Holes in Balsa Wood
It’s not like you can’t drill into balsa wood. Just using normal woodworking techniques doesn’t work well on balsa and you have to resort to other methods.
You can definitely drill balsa wood, but not with a standard handheld drill. The best way to cleanly drill through balsa wood is when you use a drill press.
What is A Drill Press
The drill press is a stationary or bench-top drill machine. It keeps the drill fixed so that one can make precise holes with it.
The drill press also allows drilling slowly while applying a low amount of to-down pressure. This feature comes in handy when drilling balsa wood as it prevents the wood from cracking down.
Still, the drill press is not the only solution. You need to use more drill bits including a drill press if you want satisfying results.
Here are some of the methods you can try it while drilling balsa wood.
Use Brass Tube to Drill
While drilling balsa wood, one of the biggest concerns is the wood getting crushed and splintered. To avoid this, the best bet is to use a brass tube with the drill.
- First, file the brass edge with a round tip filer to sharpen it
- Then, mount the brass tube on the drill
- Mark the spot where you planning to drill and place it under the tube
- Start the drill
- Gradually lower the drill to apply pressure and make a hole
- After drilling, a cylindrical shaped wood piece will be stuck inside the brass tube
- Finish the job by removing the circular wood piece from the tube
Drill with Drill Bits
Another excellent way to drill balsa wood would be using a drill bit. Using drill bits is not only functional but also provides you with better and more options. You
can use different types of drill bits depending on the size and thickness of the balsa wood.
Spur Wood Drill Bits
As mentioned earlier, the main problem with drilling holes in balsa wood is that the hardness of the wood is low for a hardwood. Due to the soft texture of the wood, it bends and presses too easily. That’s why while drilling, the holes can end up misaligned from the marked spot. Furthermore, with more pressure applied, the wood may break even.
So, to solve this issue, you can drill in balsa wood using spur drill bits. First, keep the drill well aligned with the wood and start at a slow speed. Gradually speed it up and let the drill finds its way inside instead of applying external pressure.
Spur Drill Bits
If you need to drill at an angle, the fast circular motion of the drill may cause it to
diverge from the drilling point and end up misaligned. To avoid this, you should initially drill vertically to make a marking point in the wood. After the wood is marked, then drill at the desired angle.
Drilling holes of larger diameters are another cause of concern, as they can crack the wood. For that, you should draw a circle first and then cut the balsa wood with a cutter. For deeper holes, you can use a saw drill bit at high speed.
Forstner Drill Bits
For drilling larger holes, you’ll find better results with hole-saw bits or Forstner drill
- First, to make a mark on the balsa wood sheet, use a thin drill bit to drill through the wood
- Use the smaller hole as a guiding point and drill the larger hole with a saw bit or Forstner bit
- Drill the hole up to the total thickness of the wood sheet
- Turn the wood sheet over and flip the sides
- Repeat the drilling process in such a way that the front side and the backside are flipped
- Slowly move the drill across the sheet depth to prevent rough edges
Forstner Drill Bits
Hole Saw Bits (Diamond)
Diamond bits are mostly used for metals, but they work nicely for Balsa wood as well. The ultra-small cutting edges drill better due to the soft nature of balsa wood.
Use Scrap Wood Platform
While drilling balsa wood, larger holes may cause cracks and tears. Sadly, it’s one of the side effects that are hard to get around. However, you can try this method to minimize the effect:
- Find a scrap wood piece bigger than the balsa wood piece you’re working on
- Place your balsa wood on the scrap piece of wood
- Hold the balsa wood and scrap wood together firmly by clamping or through some other approaches
- Make sure the balsa wood doesn’t move on the scrap wood platform while drilling
- Align the drill with the marked point of the hole on the balsa wood
- Slowly exert pressure on the sheet of balsa wood in such a way to ensure the pressure is distributed evenly when drilling
- To drill deeper, move the drill bit or brass tube up to the depth of the wood
- Remember to wear a face mask, safety glasses, protective clothes, and gloves during drilling so the wood dust particles don’t cause irritation on your eyes, nose or skin.
Glue Paper on Both Sides
Paper both side with copy paper and spray glue and then use a Dremel on high speed to drill a hole on balsa. Don’t apply glue to the wood, but rather to the paper. If you don’t go overboard with the glue, you can easily peel off the paper after finishing your drilling.
You can also seal the balsa wood with highly effective glue to prevent tear-out when drilling. Normal PVA wood glue, as well as epoxy and cyanoacrylate adhesives, etc., are used for assembling balsa wood. The glue hardens the surface of the wood and provides a hard shell thus making the drilling process neat and clean.
Punch Holes in Balsa Wood
If you don’t have a drill, you can punch out a hole using a sharp brass tube. Rotate the tube with your hands to drill into the wood. But remember not to use this method on thicker sheets as the punch can press it all together.
Or you can use a crafter hole punch to create a round hole. You should place the balsa wood properly through the paper holder so there’s less chance of splintering.
How to Drill Multiple Balsa Wood Sheets
The thickness of balsa wood largely dictates the state of splintering or tearing out. The thinner the wood, the more chance there will be uneven pressure by brass tube or drill bits. And as a result, the greater the chance of wood splintering.
If you’re planning on drilling multiple holes in a few sheets of balsa all at once, you need to hold them tight together. To do so, you should place some weight on both ends.
In this case, taping is a good idea.
Try taping identical pieces of balsa wood on the front and back. Tightly tape them back, and then powerfully drill through all three pieces. That way, the front and back pieces of wood may splinter, but the centerpiece will remain intact.
What is difference between basswood and balsa wood?
Basswood is another lightweight wood similar to balsa. However, basswood has better and is less prone to warping. It doesn’t change its shape or density when stored in humid conditions, unlike balsa wood.
How to cut balsa wood?
Balsa wood should always be cut with a sharp knife, for instance, a crafts knife. It’s best to cut in a series of strokes, each one cutting farther and deeper through the wood. Don’t try to cut it in one go or put too much pressure on the knife. Because too much pressure applied will make the wood crushed not cut.
If you want to cut larger balsa wood planks, you should use a saw with multiple teeth.
When to use a drill press over a hand drill?
The best advantage a drill press has over a hand drill is accuracy. If you need to drill holes at a precise angle or drill holes of identical size, position, and depth, the drill press will make the job easier for you. It’s faster and more accurate. Plus, if you drill by hand at an angle, there’s a chance you may slip and get less than perfect results.
What happens if the balsa wood is drilled too slowly?
If the balsa wood is drilled too slowly, chances are the machine may catch more wood grain. That may result in wood getting torn up. Therefore, it’s better to drill at a high but consistent speed for satisfying results.