The boom is what makes an EWP an EWP — it carries the platform out and up and holds it there while someone works. It is also the most exposed part of the machine to damage, swinging through the air near structures, and the most consequential to get wrong, because it is the long lever holding a person aloft. A dent that looks cosmetic can be the start of a buckle or the notch that seeds a crack, and on a telescopic boom, damage to one section can jam or gouge the sections that slide inside it. This guide covers how booms get damaged, why appearances deceive, and how boom damage is properly assessed and repaired.
Symptoms of boom damage
Boom damage presents as:
- Dents and gouges in the boom sections, which locally weaken the member and can act as the starting point for a buckle or crack.
- Visible bends or distortion in a boom section, a serious sign that the structure has been overstressed.
- Cracks at welds, boom-section joints, lugs and pivot points, which on a boom are a critical-component concern.
- Telescopic sections that no longer extend or retract smoothly, judder, or show scoring on the slide surfaces.
- Damaged, worn or misadjusted wear pads and slide surfaces on telescopic booms, causing rubbing and uneven movement.
What causes boom damage
- Impact — striking structures, buildings, trees or other plant while slewing or manoeuvring the boom.
- Overloading and shock loading, which put stresses through the boom beyond what it is designed to carry.
- Fatigue cracking at the highly stressed welds and joints after years of lift, slew and lower cycles.
- Corrosion, which thins boom sections and pits the surface where fatigue cracks begin.
- Contamination, wear-pad neglect and lack of lubrication on telescopic booms, which score the slide surfaces.
Why a dent is not just cosmetic
It is tempting to treat a dent as panel damage, but a boom is a load-bearing member, not bodywork. A dent reduces the section's ability to resist buckling exactly where the metal has been pushed in, and the sharp edges of a gouge or crease act as stress raisers where a fatigue crack can start. On a telescopic boom the consequences compound: a dent in an outer section can foul the section sliding inside it, gouging the slide surface and jamming the boom.
That is why a boom dent is assessed on its effect on the structure, not on how it looks. The judgement of whether a dent can stay, must be repaired, or condemns a section is engineering, not cosmetics.
How boom damage is assessed and repaired
Booms are examined visually for dents, bends and distortion, and their critical welds are crack tested rather than passed by eye — magnetic particle and ultrasonic methods find the cracks a look cannot. This scrutiny is central to the major inspection, which AS 2550.10 schedules at the 5-year point for some equipment classes and the 10-year point for others, when the boom is disassembled far enough to test its welds and pins directly.
- Withdraw the machine from use and map how far the damage runs, crack testing suspect welds and sections.
- Assess dents and distortion for their structural effect; where a section is beyond repair it is replaced rather than patched.
- Gouge out any crack in full and lay down a fresh weld to a written procedure using the right filler, then re-test the repair.
- Restore telescopic slide surfaces and renew wear pads so the sections run true, correctly adjusted and lubricated.
- Function test the boom through its full range, re-check for smooth extension and retraction, recoat and document the work.
Keeping the boom sound
Careful operation prevents most boom damage — watching the boom near structures, respecting rated capacity, and avoiding the shock loads that overstress the sections. On telescopic booms, keeping the slide surfaces clean and lubricated and the wear pads maintained stops the scoring and juddering that damage the sections.
Keeping the boom clean and coated denies corrosion the pit it needs to seed a crack. Any dent, bend or crack on a boom should stop the machine and be assessed by a competent person, because the boom is the one part of the machine that is holding a person in the air.
This guide is general information prepared by EWP Australia and is grounded in publicly available Australian Standards and Safe Work Australia material. It is not a substitute for the current published edition of the relevant standard or for site-specific engineering advice. Always work from the current standard and consult a competent person for your specific equipment and application.