What are the Differences Between Developers, and Which Should I Use For Penetrant Inspections?

  •  

Developers enhance the visibility of penetrant indications, in this blog we explore the various forms and learn what makes them different

By Cheri Stockhausen, Product Application Manager

How do developers work?

Developers enhance the visibility of penetrant indications by pulling penetrant from a surface open discontinuity and spreading the penetrant through the developer coating on the part surface. The penetrant indication may appear larger than its actual size as the penetrant spreads through the developer over time. Specifications state minimum and maximum development times to address the spread of penetrant through developer. The minimum development time should allow enough time for penetrant to be pulled from the surface open flaw and spread on the part surface for enhanced visibility. The maximum development time is in place to minimize excessive penetrant “bleed out” from an indication that could potentially obscure the indication.

Developers also increase the contrast between the penetrant and part background. With fluorescent penetrant inspection, the developer coating decreases glare from shiny part surfaces when viewed under UV light, highlighting penetrant indications and reducing eye fatigue of inspectors. With visible penetrants, developers provide a white background so that red dye penetrant indications are easy to identify.

Developers are available in various forms. Always review applicable specifications and company test procedures to identify approved developer options.

 

Types of Developers

Dry Powder Developers

Dry powder developers are fluffy white powders that may be applied manually with powder spray bulbs or spray guns or by dipping and dragging parts in the dry powder developer. In automated penetrant systems, dry powder developers are applied in swirl cloud or dynamic cloud chambers.

Dry powder developers deposit a light dusting on the part surface and are only suitable for Type 1 fluorescent penetrant inspections. Specifications prohibit the use of dry powder developers with Type 2 visible dye penetrant inspections since dry powder developers would not provide an adequate white contrasting background for visible dye penetrants.

Water Soluble Developers

Water soluble developers are supplied in powder form and are mixed with water according to the manufacturer’s directions. The supplied powder will dissolve in water and only requires agitation during the solution preparation. Water soluble developers are only for use with fluorescent penetrants. Water soluble developers may not be used with Type 2 visible dye penetrants because, like dry powder developers, water soluble developers do not produce an adequate white contrasting background that is necessary for visible dye penetrant inspection.

Water Suspendible Developers

Like water soluble developers, water suspendible developers are supplied in powder form and mixed with water according to the manufacturer’s instructions. However, water suspendible developers do not dissolve in water. Instead, they form a developer suspension. The developer suspension must be continuously agitated to provide a consistent developer concentration. Water suspendible developers may be used with both Type 1 fluorescent and Type 2 visible dye penetrants since water suspendible developers produce a suitable white developer coating that enhances both visible dye and fluorescent penetrant indications.

Nonaqueous Developers

Nonaqueous developers are supplied ready to use. Spray is the preferred application method for nonaqueous developers, and aerosol cans are a convenient option. Nonaqueous developers contain white powders suspended in volatile solvents and require mixing prior to use. When applied by spray, the solvent evaporates and leaves a dry white developer coating on the part surface. Nonaqueous developers are suitable for both Type 1 fluorescent and Type 2 visible dye penetrant inspections.

Parts must be completely dry before application of dry powder and nonaqueous developers. Water soluble and water suspendible developers are applied to wet parts after the penetrant rinse removal step. Parts are typically dried in a hot air dryer after application of water soluble or water suspendible developer.

Non-Aqueous Wet Developer Aerosols

Non-Aqueous wet developer aerosols are powder particles mixed with a quick drying solvent. The powder is suspended in the solvent and is sprayed onto a substrate. The solvent evaporates, leaving an opaque white coating and contrasting background for fluorescent and visible penetrant inspections. The product is available in an aerosol can for quick and easy inspection in the field. Aerosol kits are available that include cleaners, developers and penetrants so each step in the process is on hand when you need it. 

 

Published September 11, 2018

Subscribe to Magnaflux News:

Want to stay up on the latest NDT insights and articles from Magnaflux? 

Subscribe to Magnaflux updates above to get fresh news delivered to your inbox once a week.

Please wait while we gather your results.

Related Blog Entries

Learn about the available properties of developers

Does Developer Dry Time Impact Indication Strength?

Learn about the available properties of developers and the relationship between dwell time and inspection quality

Read More...

UV-A Intensity: What’s Special About 5,000 µW?

UV-A Intensity: What’s Special About 5,000 µW?

Most UV-A lamps on the market are set to provide 5,000 µW/cm2 at a distance of 15 in / 38 cm. What’s so special about those numbers?

Read More...

Liquid Penetrant Aerosol Coverage Test

NDT Visible Liquid Penetrant Aerosol Coverage Test [Video]

See how three popular visible liquid penetrants perform in a coverage test to learn how many square feet each can covered

Read More...

Overview of Liquid Penetrant Inspection and Magnetic Particle Inspection Specifications

Overview of Liquid Penetrant Inspection and Magnetic Particle Inspection Specifications

Understanding ASTM and SAE/AMS specifications to select the corresponding Magnaflux product for Liquid Penetrant and Magnetic Particle Inspections

Read More...

NDT UV LED Lamps

Frequently Asked Questions About NDT UV LED Lamps

Frequently Asked Questions About NDT UV LED Lamps

Read More...

This technical paper shows examples of how Magnaflux can customize liquid penetrant equipment to me

Liquid Penetrant Equipment – Customized Solutions for Unique Needs

This technical paper shows examples of how Magnaflux can customize liquid penetrant equipment to meet part size and floor space requirements

Read More...

Benefits of Developer

Benefits of Using Developer During Liquid Penetrant Inspection [Case Study]

Learn how a automotive manufacturer increased indication detection in visible and UV light with developer.

Read More...

Visible Liquid Penetrant Inspection

Better Weld Inspections with Dye Penetrant [Case Study]

Learn how one engineering and fab company improved their NDT weld inspection quality with SKL-WP2 dye penetrant.

Read More...

Magnaflux Penetrant Testing

Exposing 10 Common Misunderstandings about Penetrant Testing

We reveal common misperceptions about liquid penetrant inspection we’ve seen in the field in recent years

Read More...

Magnaflux Penetrant Inspection

Higher Sensitivity Penetrant Improves Inspection Quality [Case Study]

In this case study, we help an aerospace customer improve inspection quality and consistency with two Magnaflux penetrants

Read More...

Magnetic Particle Crack Comparison

How Brightness and Contrast Impact NDT Inspections

How perception and vision can have a significant impact on probability of detection in non-destructive testing inspections.

Read More...

Dye Penetrant Testing on Pipe

How Low Temperatures Impact Dye Penetrant Testing

Learn how lower inspection temperatures affect the performance of dye penetrant testing cleaners, penetrant and developers

Read More...

Magnaflux Dye Penetrant Testing

How to Do Visible Dye Penetrant Testing [Video]

Watch an overview of the dye penetrant testing method according to ASTM E1417, including basic steps for NDT with an AMS 2644 Type 2 penetrant.

Read More...

Liquid Penetrant in Dip Tank

How to Maintain Penetrant Testing System Performance

Learn how liquid penetrant testing products lose performance over time and what to do to ensure penetrant test reliability.

Read More...

Dye Penetrant Infographic

The Ultimate Guide to Visible Dye Penetrant Testing [Infographic]

Some handy tips for beginners who are new to visible dye penetrant testing or NDT pros who want an easy reference guide.

Read More...

PeneCert Test Services

Understanding PeneCert Test Services [SlideShare]

Learn more about test services for in-use penetrant, emulsifiers and developers to comply with ASMT E1417 and AMS 2644.

Read More...

Magnaflux Penetrant Inspection

Understanding Type-, Batch- and In-Use-Testing for Liquid Penetrants [Case Study]

Learn the differences between type testing, batch testing and in-use testing for NDT liquid penetrants.

Read More...

Liquid penetrants for leak detection of ventilation systems

Using Fluorescent Penetrant for Ventilation System Leak Detention [Case Study]

Learn how to look at the recommended actions associated with the chemical risk assessment.

Read More...

AMS 2644 Penetrant Sensitivity Levels

A Guide to AMS 2644 Penetrant Sensitivity Levels

Understand fluorescent liquid penetrant sensitivity levels and how to find the right one for your application

Read More...

Penetrant Testing Demo

How to Do Fluorescent Liquid Penetrant Testing [Video]

Watch a demonstration of the penetrant inspection method according to ASTM E1417, including basic steps for NDT with an AMS 2644 Type 1 penetrant.

Read More...

Leak-Detection-Penetrant-Testing

Leak Detection with Penetrant Testing Process

Read more about using penetrant testing products to inspect for leaks by using fluorescent or visible/colored penetrant to enhance visual detection of leaks.

Read More...

Magnaflux Water Washable Penetrant

Water Washable versus Post Emulsifiable Penetrant – Which is Right for You?

Learn the differences between water-removable and non-water-washable liquid penetrant to figure out which is right for you

Read More...

Subscribe to Magnaflux News:

Magnaflux

155 Harlem Avenue
Glenview, IL 60025, USA
Telephone: +1 847-657-5300
Fax: +1 847-657-5388
Contact Magnaflux Customer Service

Select Your Country North America Mexico Brazil China Europe Russia India New Zealand, Australia, Japan, Southeast Asia
© 2018 Magnaflux - all rights reserved.
top

We have placed cookies on your computer to give you the best possible experience with our website. These cookies are also used to ensure we show you advertising that is relevant to you. If you continue without changing your settings, you are agreeing to our use of cookies to improve your user experience. You can click the cookie settings link on our website to change your cookie settings at any time.