How to Repair a Worn Shaft Using a Forming Technique

You can repair a worn shaft using a former by rebuilding the worn area with Belzona 1111 (Super Metal), clamping the former in place to shape the repair, and allowing the material to cure before finishing the surface.

Shafts often operate in immersed or semi-immersed conditions, making them vulnerable to corrosion, chemical attack, vibration, friction, and abrasive media. Left unaddressed, worn shafts can shut down entire machines, halting production and causing significant revenue loss.

Key Takeaways: Repair Method, Materials & Tools:

  • Proper surface preparation is critical — the shaft must be cleaned, undercut, and degreased to ensure strong adhesion of the repair material.
  • Using a former allows the shaft to be rebuilt accurately to its original dimensions without extensive machining.
  • Belzona 1111 (Super Metal) provides a cold-curing, corrosion-resistant repair solution that can be machined after curing.
  • Applying release agent to both the former and surrounding shaft area ensures easy removal after the repair has cured.
  • The forming technique enables fast, cost-effective in-situ shaft repairs, reducing equipment downtime and avoiding expensive shaft replacement.
Former used to repair worn shaft

Step-By-Step Guide to Shaft Repair with a Forming Technique:

STEP 1:

Clean the Worn Shaft

Thoroughly clean the area to remove all the grease, dirt and other surface contaminants.

Step1 clean the worn shaft area
Step 2 undercut worn shaft area

STEP 2:

Undercut the Shaft

One grinder fitted with a suitable disk to undercut the shaft by 1/16″ (1.5 mm) around the circumference.

STEP 3:

Degrease the Worn Shaft

Clean the prepared area with Belzona 9111 (Cleaner/Degreaser) to remove all surface contaminants.

Step 3 clean the undercut shaft
Step 4 apply release agent to former

STEP 4:

Apply Release Agent

Apply Belzona 9411 (Release Agent) to the internal surface of the former.

STEP 5:

Apply Release Agent to the Damaged Shaft

Apply Belzona 9411 (Release Agent) to the area surrounding the repair area.

Step 5 apply release agent to damaged shaft
Step 6 mix Belzona 1111

STEP 6:

Mix Belzona 1111 (Super Metal)

Thoroughly mix Belzona 1111 (Super Metal) 2-part epoxy paste for metal repair until a uniform color, free of any streakiness, is achieved.

STEP 7:

Wet Out Former

Apply a thin layer of the mixed Belzona 1111 (Super Metal) on the internal surface of the former.

Step 7 wet out former
Step 8 apply material to worn shaft

STEP 8:

Firmly Apply Shaft Repair System

Apply a thin layer of the mixed material onto the shaft, pressing down firmly into the roughened profile.

STEP 9:

Form a Peak

Form a peak towards the center of the application area.

Step 9 form a peak
Step 10 position shaft former around the shaft

STEP 10:

Position Shaft Former

Position the former around the shaft.

STEP 11:

Clamp Shaft Former

Secure the former in position with fasteners ensuring that the excess material is extruded from the ends of the former.

Step 11 clamp the shaft former
Step 12 remove excess material

STEP 12:

Remove Excess

Remove excess material and allow the applied material to cure.

STEP 13:

Remove Former

Once cured, carefully remove the bolts and the former.

Step 13 remove former
Step 14 smooth down the surface

STEP 14:

Smooth Down

Smooth out the surface of the application area with an emery cloth.

Belzona 1111

Real-world examples of this repair method used in industry:

clarifier shaft location

CLARIFIER SHAFT REPAIR

In situ repair of a damaged shaft using Belzona.

Vacuum pump shaft being repaired

LIQUID RING VACUUM PUMP SHAFT REPAIR

In-situ shaft repair for coal mine vacuum pump.

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Frequently asked questions

Using a former with a high-performance epoxy composite is one of the most effective ways to repair a worn shaft without expensive replacement or welding. This method rebuilds the damaged area to its original dimensions while reducing downtime, preserving alignment, and avoiding heat distortion commonly associated with traditional metal repair techniques.

Yes. Many worn shafts can be repaired in situ using a former and engineered repair composite materials. On-site shaft repair is commonly used in mining, marine, manufacturing, and power generation industries because it minimises equipment removal, reduces downtime, and lowers maintenance costs compared to full shaft replacement.

Composite shaft repair methods are widely used across industries including:
 
  • Mining and mineral processing
  • Marine and offshore
  • Manufacturing and processing plants
  • Water and wastewater facilities
  • Power generation
  • Pulp and paper
  • Oil and gas
 
These industries rely on shaft restoration techniques to extend equipment life and avoid costly production interruptions.
Composite shaft repair methods are widely used across industries including:
 
  • Mining and mineral processing
  • Marine and offshore
  • Manufacturing and processing plants
  • Water and wastewater facilities
  • Power generation
  • Pulp and paper
  • Oil and gas
 
These industries rely on shaft restoration techniques to extend equipment life and avoid costly production interruptions.

When correctly applied, a composite shaft repair can provide long-term service life comparable to or better than traditional repair methods. Modern industrial repair composites are engineered to withstand heavy loads, wear, corrosion, and chemical exposure, making them suitable for demanding operational environments. Proper surface preparation and correct use of the former are critical to achieving maximum durability and performance.