How To Remove Broken Screw From Plastic

Removing a broken screw from plastic can be a delicate operation, but with the right tools and techniques, it's entirely achievable. This comprehensive guide will walk you through various methods, providing you with the knowledge and confidence to tackle this common DIY challenge.

Understanding the Challenge

Plastic, unlike metal, is more prone to cracking or breaking when subjected to stress. A broken screw lodged in plastic presents a unique problem because the plastic itself may be fragile or already damaged. Successfully removing the screw requires a careful approach that minimizes further damage to the surrounding material. Before starting any removal process, it's essential to assess the situation. Consider the type of plastic, the size of the screw, and how deeply it's embedded. This assessment will help you choose the most appropriate method.

Essential Tools and Materials

Having the right tools at your disposal is crucial for a successful screw extraction. Here’s a list of items you might need:

Screw Extractors: These specialized tools are designed to grip and remove damaged screws.
Left-Handed Drill Bits: These bits can sometimes catch and back out the screw as you drill.
Drill: A power drill or cordless drill with variable speed settings.
Pliers: Needle-nose pliers or locking pliers for gripping and twisting.
Screwdrivers: A set of screwdrivers, including flathead and Phillips head, for attempting to grip the screw head.
Heat Gun or Hair Dryer: To gently soften the plastic (use with caution).
Super Glue or Epoxy: For bonding a tool to the broken screw (use as a last resort).
Lubricant: Penetrating oil or WD-40 to help loosen the screw.
Safety Glasses: To protect your eyes from debris.
Gloves: To improve grip and protect your hands.
Precision Knife or Hobby Knife: For carefully cleaning around the screw.
Center Punch: To create a starting point for drilling.
Rubber Bands or Steel Wool: To improve screwdriver grip.

Methods for Removing a Broken Screw from Plastic

Several methods can be employed to remove a broken screw from plastic. The best approach depends on the severity of the break and the type of plastic involved. Here's a detailed look at each technique:

1. The Screwdriver and Rubber Band/Steel Wool Trick

This method works best when a portion of the screw head is still accessible. The goal is to improve the grip of your screwdriver.

Step 1: Preparation: Select a screwdriver that closely matches the screw head.
Step 2: Apply the Grip Enhancer: Place a wide rubber band or a small piece of steel wool over the screw head.
Step 3: Insert the Screwdriver: Press the screwdriver firmly into the screw head, applying pressure through the rubber band or steel wool.
Step 4: Attempt to Unscrew: Slowly and steadily turn the screwdriver counterclockwise. The added friction from the rubber band or steel wool may provide enough grip to extract the screw.
Step 5: Persistence: If the screw doesn't budge, try applying a small amount of penetrating oil around the screw head and let it sit for a few minutes before trying again.

2. Using Pliers

If a significant portion of the screw is exposed, pliers can be used to grip and turn it.

Step 1: Grip the Screw: Use needle-nose pliers or locking pliers to firmly grip the exposed part of the screw.
Step 2: Apply Pressure: Ensure the pliers have a solid grip to avoid slipping.
Step 3: Rotate and Extract: Slowly rotate the pliers counterclockwise, applying steady pressure.
Step 4: Wiggling: If the screw is stuck, try gently wiggling it back and forth while applying turning force. This can help to loosen it.
Step 5: Lubrication: As with the previous method, penetrating oil can be helpful.

3. Heat Application

Applying gentle heat can soften the plastic, making it easier to remove the screw. However, caution is essential because excessive heat can melt or damage the plastic.

Step 1: Heat the Area: Use a heat gun or hair dryer on a low setting to gently heat the plastic surrounding the screw.
Step 2: Test the Plastic: Periodically test the plastic's flexibility by gently probing it with a tool. You want it to soften, not melt.
Step 3: Attempt Removal: Once the plastic is slightly softened, try using a screwdriver or pliers to remove the screw.
Step 4: Cooling: Allow the plastic to cool down slowly after the attempt.

4. Screw Extractor Kit

Screw extractors are specialized tools designed for removing damaged screws. They come in various sizes to match different screw diameters.

Step 1: Prepare the Screw: Use a center punch to create a small indentation in the center of the broken screw. This will help guide the drill bit.
Step 2: Drill a Pilot Hole: Select a drill bit that is slightly smaller than the screw extractor. Carefully drill a pilot hole into the center of the broken screw. The depth of the hole should be about half the length of the screw.
Step 3: Insert the Screw Extractor: Insert the screw extractor into the drilled hole.
Step 4: Rotate Counterclockwise: Apply steady pressure and rotate the screw extractor counterclockwise. The extractor's threads will grip the screw, and as you turn, it should back out the broken screw.
Step 5: Controlled Force: Avoid applying excessive force, which could break the extractor or further damage the plastic.

5. Left-Handed Drill Bit

Left-handed drill bits are designed to catch and back out the screw as you drill.

Step 1: Center the Drill: Use a center punch to create a starting point in the middle of the broken screw.
Step 2: Select the Bit: Choose a left-handed drill bit slightly smaller than the diameter of the screw.
Step 3: Drill Slowly: Drill into the screw at a slow, steady speed. Apply consistent pressure.
Step 4: Monitor for Movement: As the drill bit bites into the screw, it may catch and begin to unscrew it.
Step 5: Complete Extraction: If the screw starts to turn, continue drilling until it is completely removed.

6. Super Glue or Epoxy Method

This method is a last resort and should be used with caution, as it can permanently bond the tool to the screw.

Step 1: Select a Tool: Choose a tool that can fit into the broken screw head, such as a small screwdriver or Allen wrench.
Step 2: Apply Adhesive: Apply a small amount of super glue or epoxy to the end of the tool.
Step 3: Bond the Tool: Carefully insert the tool into the broken screw head and hold it firmly in place until the adhesive sets. This may take several minutes.
Step 4: Attempt to Unscrew: Once the adhesive has fully cured, try to unscrew the broken screw by turning the tool counterclockwise.
Step 5: Caution: Be careful not to apply excessive force, which could break the bond or damage the plastic.
Step 6: Clean Up: If successful, carefully remove any excess adhesive from around the screw hole.

7. Creating a New Slot

If the screw head is damaged but still partially accessible, you can create a new slot for a flathead screwdriver.

Step 1: Use a Rotary Tool: Equip a rotary tool (like a Dremel) with a cutting disc.
Step 2: Cut a Slot: Carefully cut a slot across the top of the screw head, creating a new groove for a flathead screwdriver.
Step 3: Select a Screwdriver: Choose a flathead screwdriver that fits snugly into the new slot.
Step 4: Attempt to Unscrew: Apply firm pressure and turn the screwdriver counterclockwise.
Step 5: Lubrication: If the screw is stuck, use penetrating oil to help loosen it.

8. Melting the Plastic Around the Screw (Extremely Risky)

This method should only be used as an absolute last resort, as it carries a high risk of damaging the plastic beyond repair.

Step 1: Controlled Heat: Use a soldering iron or a precision heat source to carefully melt the plastic directly around the screw. The goal is to weaken the plastic's grip on the screw without completely destroying the surrounding area.
Step 2: Gradual Removal: As the plastic softens, use pliers or a small screwdriver to gently try to turn and extract the screw.
Step 3: Extreme Caution: Work slowly and deliberately, pausing frequently to allow the plastic to cool slightly and assess the situation.
Step 4: Repair Considerations: Be prepared to repair or replace the plastic component if this method goes wrong.

Preventing Future Problems

Prevention is always better than cure. Here are some tips to prevent screws from breaking in plastic in the future:

Use the Right Size Screws: Ensure you are using screws that are appropriate for the size and type of plastic.
Avoid Overtightening: Overtightening screws is a common cause of breakage. Tighten screws until they are snug, but avoid excessive force.
Pre-Drill Holes: When screwing into hard plastics, pre-drilling pilot holes can prevent the plastic from cracking.
Use Lubricants: Applying a small amount of lubricant to the screw threads can reduce friction and prevent the screw from binding.
Choose the Right Screwdriver: Use a screwdriver that properly fits the screw head to avoid stripping the head.
Consider Plastic Screws: For some applications, plastic screws may be a better option than metal screws, as they are less likely to damage the plastic.

Safety Precautions

Wear Safety Glasses: Always wear safety glasses to protect your eyes from flying debris.
Use Gloves: Wear gloves to improve your grip and protect your hands.
Work in a Well-Ventilated Area: If using chemicals like penetrating oil or super glue, work in a well-ventilated area.
Be Careful with Heat: When using a heat gun or soldering iron, be extremely cautious to avoid burns or fire hazards.
Unplug Power Tools: When changing drill bits or making adjustments, always unplug power tools.
Take Breaks: If you are working on a difficult screw, take breaks to avoid fatigue and maintain focus.

Conclusion

Removing a broken screw from plastic can be a challenging task, but by following these methods and taking the necessary precautions, you can successfully extract the screw without causing further damage. Remember to assess the situation, choose the right tools, and work carefully and patiently. With a bit of perseverance, you'll be able to overcome this common DIY obstacle and restore your plastic items to their original condition. Good luck!