Clearer Views, Better Data: A CWI’s Guide to Video Borescope Inspection

For decades, the primary tools of the AWS Certified Welding Inspector (CWI) were simple: a flashlight, a mirror, a fillet gauge, and a keen pair of eyes. But as engineering designs become more complex and tolerances tighten, the areas that require nondestructive examination (NDE) are becoming increasingly difficult to access.

Enter the industrial video borescope, a remote visual inspection (RVI) tool packed with adjustable lighting, photography, videography, annotation, and often measurement capabilities that elevate welding inspections to new heights. However, possessing the tool is only half the task. A borescope is not simply a camera on a wire; it is a sophisticated optical instrument that requires a few simple techniques and care guidelines to yield accurate results.

This article explores best practices for leveraging borescope technology to identify discontinuities such as porosity, incomplete penetration, and burn-through, ensuring that what we see on the screen accurately reflects the weld’s quality.

Beyond the inspection, we will also explore the often overlooked post-inspection phase and cover proper reporting techniques. Finally, we will demystify the purchasing process by breaking down exactly which features matter for welding applications, helping you make an informed decision for your specific needs.

Best Inspection Techniques

The biggest hurdle for CWIs performing borescope inspections is image clarity. The issue is not solely the camera’s resolution, but also how the operator manages the environment. Inside a stainless-steel pipe or a polished pressure vessel, for example, the environment is hostile to photography. It is dark, reflective, and geometrically complex.

Mastering the Light

Lighting is the single most critical factor in borescope inspection. A common mistake is immediately cranking the lighting output to 100%. In a reflective welding environment, this causes “blooming” where the light bounces off the metal surface and blinds the camera sensor, washing out the details of the weld bead — Figs. 1 and 2.

• Dial in the exposure. Use the brightness controls to find the optimal lighting level. Often, lower light allows the sensor to capture contrast better. When your target area is close — for instance, when inspecting a root pass in a small diameter tube — back the lights down.  Also, take advantage of modern borescope’s exposure control settings to reduce glare in tight or reflective areas.
• Angle of incidence. If glare persists, slightly articulate the tip. Changing the camera angle relative to the weld surface by just a few degrees can often deflect glare away from the lens.

Stability and Image Capture

Blurry images are the enemy of good reporting. Unlike a regular digital single-lens reflex (DSLR) or mirrorless camera, a borescope has a small sensor and often uses a slower shutter speed in low light.

• Stabilize the instrument. The steadier you hold the handset and the insertion tube, the sharper the image. If possible, brace your hand against the pipe entry or a solid surface.
• The “rule of multiples.” Never take just one picture. When you identify a relevant indication, whether it is a cluster of porosity or a suspected crack, capture three to four images from slightly different angles or lighting intensities. This redundancy ensures you are not stuck with a single, ambiguous photo that would require a reinspection.

Video Inspection Technique

Video offers context that still images cannot. However, erratic camera movement will make reviewing the footage difficult. A pro tip for video inspection of linear welds (like longitudinal pipe seams) is the “insert-and-pull” method:

1. Insert the probe all the way to the end of the inspection zone
2. Orient the camera to the 12 o’clock position (or your specific target)
3. Start recording
4. Slowly and steadily pull the insertion tube out toward you. This method is smoother than pushing the probe in, as the tension on the tube helps keep the camera head steady.

Finally, though borescopes have built-in screens, connecting them to a larger monitor or other devices via HDMI or Wi-Fi can significantly enhance defect recognition and facilitate real-time team collaboration.

Accessories

Borescopes do the heavy lifting during a weld inspection, but the right accessories can make the job easier. One accessory CWIs find helpful is the centering device — Fig. 3. This attachment for the insertion tube helps keep the scope centered in the pipe, providing a consistent view of the weld around the entire circumference. That means better lighting and fewer blind spots. It also helps protect the scope from rubbing against the wall.

Other add-ons, such as stiff yet flexible guide tubing or rigidizers, can improve control during insertion. They add stiffness when you need it, making it easier to push through longer runs or tight areas without fighting the scope. These accessories are not mandatory for every job, but they are good tools to have if needed.

Annotation and Context

The last step of any inspection is the signed report. In the world of RVI, where the image is the data, visual evidence must be definitive.

A close-up photo of a crack looks exactly like a close-up photo of a crack from a different inspection. Always use the text annotation features on your device to label images immediately — Fig. 4. Ensure the date and time stamp are active, and clearly identify the weld number, the specific quadrant or clock position, and the direction of the view. One more tip: Set up image folders before starting the inspection. A little prep work upfront keeps your files organized and makes inspecting and reporting more efficient.

Verification vs. Estimation

Historically, sizing a defect via a borescope was a guessing game. Today, on-screen measurement technologies such as stereo and 3D measurement allow inspectors to quantify defects with high precision. While not every inspection requires this level of detail, these tools are invaluable for critical validation. If you spot a pore or an undercut that looks borderline, using these measurement tools can provide the data needed to accept or reject the weld based on specific code criteria (e.g., American Society of Mechanical Engineers [ASME] B31.3, Process Piping). Even if you don’t use advanced measurement, having a reference object of known size in the frame can help in estimating the scale of the flaw.

Streamlining the Paperwork

A disorganized folder of JPEGs can quickly become a reporting nightmare. Many borescopes now offer inspection reporting software designed to automate code-compliant reports with a few clicks, no more clicking and dragging — Fig. 5. Look for solutions that let you flag images and add comments, such as International Organization for Standards (ISO) or ASME codes. This not only speeds up turnover packages but ensures your data is consistent, searchable, and professional.

Best Practices for Care of the Borescope

A video borescope is a fine optical instrument housing tiny charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) sensors, hair-thin wires, and complex articulation cables within a ruggedized exterior that shields an intricate optical assembly.

Common Handling Pitfalls

1. The coiled hose error. Whether mechanical or servo motor, do not operate the articulation joystick if the insertion tube is coiled in a tight loop (like a garden hose). This puts immense tension on the internal cables. If you feel unusually high resistance on the joystick, stop.
2. Protect the bending section. The most sensitive part of the scope is the bending section where the borescope articulates. Never grab the bending section and maneuver it with your fingers. Only use the joystick or control knobs to move the tip. Manually forcing it can strip the internal gears or snap the cables.
3. The yank. If the probe seems stuck, perhaps caught on a burr or a tack weld, resist the urge to yank it. Forceful pulling will stretch the outer braiding and damage the data wires. Instead, gently manipulate the joystick to wiggle and steer the head free while applying light tension.

Environmental Limits

Welds can be hot, and electronics can only withstand so much heat. A standard mistake is rushing to inspect a weld before it has cooled.

• Temperature. Refer to your user manual for the maximum heat capacity of your borescope. Extreme heat can delaminate the camera lens and fry the sensor.
• Chemical compatibility. Be mindful of cleaning agents. The insertion tube is often coated with materials resistant to oil and water, but harsh solvents can degrade this coating over time. Again, refer to your user manual.

Daily Hygiene

Avoid letting the camera tip fall onto hard concrete floors. When packing up, ensure the insertion tube isn’t draped where it can be stepped on or crushed by equipment cases. Clean then store your borescope in its provided case, leaving it ready for the next inspection. These sound like basics, but impact damage and crushing are the leading causes of premature borescope failure.

Considerations when Purchasing a Borescope

If you are in the market for a unit to support your welding inspections, it is easy to get lost in spec sheets. Below is what matters for weld inspection.

• Scope type. The articulating video borescope has become the versatile standard for complex welding inspections. However, rigid and semirigid borescopes are available for straight-line access or simple overhead checks.
• Versatility. When comparing units, consider how the system achieves different viewing angles. Many systems use interchangeable optical adapters or screw-on tips to switch between a forward and a side view. Alternatively, dual- or triple-camera probes integrate multiple lenses into a single tip, allowing the operator to toggle between views electronically without retracting the insertion tube to swap components.
• Articulation. You generally have a choice between 2-way (left/right) and 4-way (360 deg) articulation. For straight runs, 2-way may suffice, but for navigating elbows, T-joints, or complex headers, 4-way articulation is often indispensable. It allows you to look back at a root pass or navigate through a lateral turn without rotating the entire insertion tube.
• Durability and materials. Look at the construction of the insertion tube. Tungsten braiding and stainless-steel construction are industry standards for a reason — 
  they offer the best balance of flexibility and armor against the rough internal surfaces of carbon steel piping.
• Diameter. The probe must fit your smallest access point with room to spare. If you are inspecting small instrumentation taps, a 0.85, 1.1, or 2.2 mm is necessary. If you have open access, a 3.9, 6.0 mm, or wider probe often offers better lighting and durability.
• Focal range. This is critical. Some borescopes are designed for far focus (seeing down a longer space). Most often, for welding, you need near focus or macro capabilities. Ensure the scope you choose is optimized for the depth of inspection you can achieve.
• Support and cost of ownership. Finally, when shopping, reputable borescope providers often offer a no-cost demonstration or trial period. This allows you to validate that the probe diameter fits your specific access points and that the image quality meets your code requirements before committing capital. During this demo, consider ease of use; an intuitive interface ensures that inspectors spend their time analyzing the weld, not fighting the menu system.

Furthermore, consider the long-term partnership with your equipment provider. In the harsh environments CWIs work in, accidental damage to the insertion tube is often a matter of when, not if. Investigate the manufacturer’s repair costs and policies: Calculate the lifetime cost of ownership by accounting for repair costs and the average turnaround time for repairs. Rapid turnaround times are essential when a project is on hold. Some providers offer borescopes on loan to negate downtime.

Conclusion

The video borescope has graduated from a novelty to a necessity in the welding inspector’s toolkit. It allows us to verify the integrity of the root, the most critical part of many welds, without destructive testing. However, the tool is only as good as the operator. By understanding how to manage lighting, prioritizing image stability, and respecting the intricate nature of this industrial equipment, we can elevate inspection standards.

As we move toward digital reporting and tighter quality standards, the ability not only to see the weld but also to capture clear, actionable data will define the next generation of professional inspection. 

CHRISTINE O’CALLAGHAN (christy@viewtech.com) is a remote visual inspection service and support specialist, and DUNCAN WHITE is director of sales and marketing at ViewTech Borescopes, Traverse City, Mich.