Ridetheducks.com is reader-supported. When you buy through links on our site, we may earn an affiliate commission. Learn more

How to Drill a Hole in Fiberglass

how to drill a hole in fiberglass

Are you looking to drill a hole in fiberglass? Fiberglass is a strong material; therefore, drilling through it to create a clean-cut hole might be tricky. However, with the right tools and techniques, beginners can get the job done right.

Whether it is for a new boat or repairing an old one, this guide will show you how to complete the task without cracking the materials.

Steps to Drill a hole in Fibgerglass

What will you Need

  • A power drill
  • A hole saw or spade bit
  • A sharp object
  • A helping hand (if you can find one)
  • A pair of safety glasses -Don’t forget to wear safety goggles when drilling to protect your eyes from debris

Step 1: Decide Where you Want to Drill it

This step may seem obvious, but it is important to take a moment and visualize where you want the hole to be. Be careful not to drill too close to the edge of the fiberglass as it can be easy to break.

Once you have a location in mind, use the sharp object you prepare to mark it with a small indentation. This will help prevent slipping while drilling and give you a guide to follow.

Step 2: Start with a Smaller Drill Bit

While it may be tempting to go straight for the hole saw or spade bit, it is always best to start with a smaller drill bit to prevent cracking or breaking the fiberglass as you drill.

Begin by drilling slowly and steadily until you have made a small pilot hole.

Step 3: Swap Out the Drill Bit for the Hole saw or Spade bit

Once you have made the pilot hole, it is time to swap out the drill bit for the hole saw or spade bit.

Be sure to use a drill that is appropriate for the size of the hole you are drilling.

  • If you are using a hole saw, make sure that the teeth face down and push the saw through the fiberglass
  • If you are using a spade bit, apply pressure while drilling to ensure that the blade goes all the way through

Step 4: Drill Until the Hole is Complete

Once you have swapped out the drill bit, it is time to start drilling! Drill slowly and steadily until the hole is complete.

Important Tips:

  • If you are having trouble getting started, try using a piece of scrap wood to help. Place the scrap wood underneath the fiberglass and drill through both simultaneously
  • If the fiberglass is thick, you may need to use a larger drill bit or hole saw. You may need to apply more pressure while drilling
  • You can use a countersink drill bit to create a beveled edge on the hole. This will help to prevent cracking and chipping
  • If you are having trouble drilling through the fiberglass, try using a lubricant such as WD-40 or soap and water
  • If you are working on a large project, it may be helpful to have an assistant hold the piece of fiberglass while you drill
  • Make sure that the drill bit is completely submerged in water while drilling to keep it cool
  • If the hole is larger than 1 inch, it is best to drill from both sides of the fiberglass to prevent cracking

How to Drill Fiberglass without Cracking

how to drill fiberglass without cracking

When drilling into fiberglass, it’s essential to go slowly and use a sharp drill bit.

It’s also helpful to use a drill bit that is slightly smaller than the circumference of the hole you’re trying to create.

If you do end up cracking the fiberglass, don’t worry. There are ways to fix it.

  • One way is to use epoxy putty. Just apply the putty to the cracks, let it dry, and then sand it down until it’s flush with the rest of the surface
  • Another way to fix cracked fiberglass is by using a gel coat. Gelcoat is a viscous liquid that can be applied to cracks and then left to harden. Once it’s hardened, it will create a water-tight seal that will prevent further damage

What type of Drill bit do you use for Fiberglass?

If you’re looking to drill through fiberglass, you’ll need a special drill bit – one that’s designed for the job. A few different types of drill bits can be used for fiberglass, but the most common is the spade bit.

  • Spade Bits are designed for drilling through thick materials like fiberglass. They have a wide, flat blade that helps clear out any debris as you drill
  • This bit is also great for making large holes in fiberglass – perfect for running wiring or plumbing through your walls
  • If you’re looking for a more precise drill bit for fiberglass, then you might want to try a carbide-tipped drill bit
  • These bits are designed specifically for drilling through hard materials. The bit’s tip is made from carbide, which is an extremely hard material. This makes the bit ideal for drilling through fiberglass without damaging the surrounding area


Drilling a hole in fiberglass can be tricky, but with the right drill bit and a steady hand, you should be able to do it without any problems.

Just remember to go slowly, use plenty of water to keep the drill bit cool, and be careful not to drill too close to the edge of the material. With a little practice, you’ll be drilling through fiberglass like a pro in no time!

5/5 - (7 votes)

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top