Penetrant Testing Blog

FWP-931A Water Containing Penetrant is Approved

Something New and Green Met-L-Chek is pleased to announce that it has AMS-2644 approval for it’s newest penetrant FWP-931A. This is a Type 1 (fluorescent) Method A (water washable) Sensitivity Level 1 penetrant. What makes this news worthy is that this is a water based penetrant not based on petroleum oil and solvents. This material is more environmentally friendly, more cost effective...

Indication Brightness

Indication Brightness In the last issue of this newsletter, we discussed the work being done at Iowa State University with regard to penetrant inspection. To  reiterate the place where you can get all of the detailed information presented at the Spring ASNT meeting, go to www.cnde.iastate.edu/faa-casr/fpi/ Once at this site, click on “Technical results”. This will lead you to a page that...

Rolls Royce RPS 702 – Approved for use materials

RPS 702 We just received a copy of Rolls-Royce specification RPS 702 that has several points worth comments as concerns materials that are approved for use. Under paragraph 2.5.1.1, certain materials listed on AMS-2644  are The Penetrant Professor now specifically listed as approved. This will make things easier for many penetrant users working to Rolls-Royce specifications. Under paragraph 2.6.1.2, non-aqueouswet developers are...

Refractometers

George Orwell wrote a wonderful story entitled “Animal Farm”, in which one of the classic events was the posting of a sign that read, “All animals are equal, but some are more equal than  others.” It turns out that with regard to the testing of emulsifier strength, like in the Orwell story, while all refractometers are presumably equal, some of the refractometers...

How to reduce the amount of penetrant background on a rough surface …

Too much background! Recently we were asked how to reduce the amount of penetrant background on a rough surface. For those familiar with castings and forgings, this is a common problem. Typical approaches to solving this problem are longer and more powerful rinses or longer emulsification times for those using the post emulsifiable method. If we take a microscope and look at...

What One Needs to Know to Perform a Quality Penetrant Inspection!

One of the services that Met-LChek provides to the NDT community is the writing, updating and editing of the various specifications and procedures related to penetrant inspection. This includes the ASNT Penetrant Handbook, which is presently undergoing updating. While reviewing the text that has been proposed, we were struck by the presentation, which included both the scientific and technical details of the...

Known Defect Test Piece part 2

Known Defect Test Piece Part Deux In the March 2016 Penetrant Professor we discussed known defect standards for penetrant inspection and introduced a new star burst type panel, the Hoffman Panel. We commented that this panel at that time had not been officially approved to the Pratt & Whitney TAM 146040 drawing. We have been advised that in this short time the...

Low/High Temperature and Penetrants

This subject was discussed in our 2nd anniversary issue of the Penetrant Professor in 1995. Funny how time flies but the questions remain the same. Every penetrant manufacturer is asked about what temperature their penetrant should be used at. In the case of Met-L-Chek penetrants, the label on the aerosol can gives the recommended use range which reflects the range specified in...

Engine Crankshaft Inspection, circa 2005

THE ENGINE CONUNDRUM Last month, we related the story of the person who wanted to inspect a crankshaft for cracks, but who didn’t want to disassemble the engine. The question that was posed was whether the penetrant could be applied to the outside of the engine to locate a flaw in the crankshaft. We did not think that there was any way...

FAA Penetrant Studies – FAA Center for Aviation Systems Reliability, Iowa State University and at Sandia laboratories

The March 2007 “Penetrant Professor” gave some preliminary insight to a study that was conducted regarding old vs new penetrant. This as well as other studies will be summarized in this months issue. The FAA has sponsored certain research efforts at the CASR (FAA Center for Aviation Systems Reliability) at Iowa State University and at Sandia laboratories. Some of the results of...

The Penetrant Process – Iowa State University

Iowa State University has done some work regarding penetrant testing. Individual topics on their work have been presented before, but this time it was all put together. We want to list some of the highlights of their work and to refer you to the places where you can look at the details of what they have done and the results that they...

The Evolution of Penetrant Specifications

A Few More Thoughts On The Evolution of Penetrant Specifications The past two issues of the PENETRANT PROFESSOR have concentrated on the historical path of the relevant qualifying documents and the journey to develop a method of measuring absolute sensitivity. While these have been extremely important in the creation of a uniform system of qualification, progress was also being made in other...

Penetrant Application & Sensitivity

Penetrant Application & Sensitivity How is the best way to apply penetrant, and does the method of application have any bearing on the sensitivity of the process? This is a question that arises from time to time. It is not a question about the sensitivity of the penetrant, which is an innate property of the material, but rather concerns the process of...

Emulsifier Concentration

One might assume that all inspectors understand what the concentration of their hydrophilic emulsifier should be. For dip tanks, most specifications require that the concentration be maintained between 17% and 20%, and for spray application that the concentration be less than 5 %. These are verified by using a refractometer and a chart that converts the refractometer reading into percentage. Surprisingly enough,...

So, What Is This (M) and What Does It Mean??

Strangely enough we get this question frequently, concerning our post emulsified fluorescent penetrants. These are listed as follows: Level 1 sensitivity – FP-94 Level 2 sensitivity – FP-93A(M) Level 3 sensitivity – FP-95A(M) Level 4 sensitivity – FP-97A(M) This nomenclature resulted from a massive change in the qualification requirements in the early 1980’s. The story goes like this: As we have described...

Solvent Remover Does Not Contain Chromates

Bad Stuff Out We recently had a request from a customer who wanted to know how he could be sure that our solvent remover contained no chromates, since this seemed to be a requirement of NADCAP. We advised him that one could not have a product listed on the QPL if it contained chromates, but he needed something in writing directly addressing...

Reader Response: Penetrant Sensitivity – LCF crack POD panels

Words from the Wise We often remind our readers that the content of this newsletter is largely driven by our readers and the interaction that we have with them. We are pleased to relate the following comments on penetrant system sensitivity that we received from Terry Kessler, which reflect the experience of a person who has spent his working life in the...

The Dilemma of How to Measure Sensitivity

The thermally cracked aluminum panel was an early method of comparing the sensitivity of one penetrant to another, and was written into the first issue of MIL-I-25135. At that time there was apparently no concept for a specific and identifiable method of quantifying absolute sensitivity, and the panel was solely used to make comparisons. But the idea for a quantitative method was...

FAQ’s from Met-L-Chek users

While some, or many, of these things can get on one’s nerves, we deal with them as simply part of the business that we are in. With a business-like attitude, we dutifully reply in whatever fashion seems appropriate, sending copies of certifications, explaining what is on our web site, pointing out that there was no identification on samples sent, or helping to...

False Representations of Met-L-Chek, beware of the salesman.

¿USED CAR SALESMEN? We have all heard the story of the used car salesman who alleged that the wreck that he was selling had belonged to “a little old lady from Pasadena” who only drove it on Sundays to go to church. Well, salesmen and saleswomen sometimes use rhetoric like this to convince a person to buy. And, as it turns out,...

Behind the Scenes, Pen-Chek & Mag-Chek “Problems”

There is a body of research going on at a couple of places that has to do with penetrant inspection. At Sandia laboratories, the following question was investigated: “If a field inspector accidentally used aged penetrant materials, would that reduce the likelihood of detecting fatigue cracks?” To investigate this question, a careful laboratory test was designed, using specimens containing low cycle fatigue...

Reprocessed Penetrant! Settled in 2005 – No Way!

REPROCESSED PENETRANT We have recently heard about a company that offers to reprocess used water washable penetrant which has failed to meet ASTM E-1417 specifications, and return it to acceptable condition. The reproces­sing is said to remove water and particulate matter. The supposed attraction of this is that the price of reconditioning the penetrant is less than the price of new penetrant. The PENETRANT PROFESSOR has reservations...

NAD Use with Type 1 and Type 2 Penetrants, New Aerosol Package, Electrostatic Penetrant Spray, Film Thickness & De-wetting, A Bit More About UV-A Intensity

NAD Use with Type 1 and Type 2 Penetrants We recently had a question concerning the type of developer to use with fluorescent penetrant. In this particular case, the person with the question was using both visible and fluorescent penetrants. He was using Met-L-Chek D-70 developer with the visible penetrant and a different brand of developer with the fluorescent penetrant. There are...