Penetrant Testing Blog

Water Content: Karl Fisher versus ASTM D95

We are getting phone calls asking why we do not use ASTM D 95 to measure the water content of penetrants and emulsifiers. ASTM E 1417 & NADCAP PRI AC7114/1 revision A, allow the use of ASTM D 95 or the modified Karl Fischer method. This latter method was introduced to ASTM E 1417 some years ago by Met-L-Chek®. The reasons for...

More About Emulsifiers and Charts

In our last issue, we pointed out that some auditors now require that the user make his or her own concentration chart for our E-58D hydrophilic emulsifier. The apparent reasoning behind this is that there is no guarantee that the refractometer used by Met-L-Chek and the refractometer in the user’s possession will give the same results. So let’s discuss how to make...

Water Pre-rinse

ASTM E-1417 states (Paragraph 7.3.4.2) that “Hydrophilic post emulsifiable penetrant shall be removed with a water Pre-rinse, application of the hydrophilic emulsifier and then a post-rinse.” There is an unanswered question as to whether this applies equally to both immersion in the emulsifier and to emulsifier that is sprayed on. The answer may be found in the ASNT Penetrant Handbook, where it...

What Do The Numbers On The Bottom Of The Can Mean

What Do the Numbers Mean We often get calls asking what the numbers mean on the bottom of the aerosol cans and how do they relate to our certification for the product. The first set of numbers is the canning or packaging date when the aerosol was filled. The next set of numbers is the canning code used by the canner to...

More Thoughts on POD’s and Penetrant Inspection

Our recent article about penetrant POD brought this response from Brian MacCracken, now retired, but an important figure in the penetrant using community: “I enjoyed this month’s Pen Prof, as I usually do. However, I would like to add my two cents about POD’s for FPI and if you want to quote me, feel free to do so. In fact, I am...

Shelf Life vs Tank Life

We frequently get questions concerning the shelf life of our products. Shelf life is a term that can be defined differently by different manufacturers, and we explain what is the practice for Met-L-Chek. This information is also contained in the literature on the Met-L-Chek web site. Met-L-Chek Company defines shelf life as the period of storage time, at ambient* conditions, during which...

Penetrant Viscosity

Penetrant Viscosity It is easy for some of us to speak about “old times” in the penetrant business. In the early days, which implies something like 30 or 40 or 50 years ago, one of the requirements of the QPL was to list the penetrant viscosity. Certificates ofcompliance with the QPL then had the viscosity of the batch of penetrant listed on...

Surface Roughness

We get a wide range of questions, from the sublime to the ridiculous. But we always understand that the question, no matter how “far out” it might seem, is an important one for the person who has asked it, andwe treat it that way. Our days are livened by some of the things that puzzle our readers, and we recentlyhad a question...

Hydrophilic Emulsifier

Hydrophilic Emulsifier We probably do not say enough times that the subjects that are addressed in this publication originate with those folks who use penetrants. The last issue featured information about hydrophylic emulsifiers, and as usual, we received comments on the article. We relish receiving comments, because they come from the users of penetrants, who have vastly more hands on experience than...

Understanding, Shades of Meaning, and Complete Obfuscation

We who work with specifications, such as ASTM E-1417, E-165, and the like are constantly reminded that it is important to be very clear. It needs to be clear to the person using the specification and it needs to be equally clear to anyone auditing the procedures. If the person working to the specification understands the requirement one way, and an auditor...

Tank Life

TANK LIFE Now we come to the term “Tank life”. Once the containers of Met-L-Chek Company products have been opened, shelf life no longer applies. If the product is in a tank or other container where it is used, the term “tank life” applies. For example, if a penetrant has a shelf life that expires on January 6, for example, and the...

Shelf Life

SHELF LIFE We frequently get questions concerning the shelf life of our products. Shelf life is a term that can be defined differently by different manufacturers, and we explain what is the practice for Met-LChek Company. This information is also contained in the literature on the Met-L-Chek® web site. Met-LChek Company defines shelf life as the period of storage time, at ambient...

Refractomers and Emulsifier Concentrations

There is a bit of turmoil concerning hydrophilic emulsifiers that we had tried to address by providing a concentration chart in our literature, and subsequently we added this to the labels on the containers. But, then there were claims that this might not be applicable to all batches. So, then we switched to providing a custom graph for each The Penetrant Professor...

Contamination

Here again, there is a lot of common sense involved. One should simply see that junk- oops, foreign material – does not get into the penetrant. But it does happen. There is the obvious poor practice of people throwing stuff into the tank. We are told that tanks have been seen with plastic water bottles floating in them, and we know of...

Mixing Batches

We do not know to what extent this subject is a problem for anyone in the USA, but it seems to have come up in Europe. There is a lot of common sense involved in this subject, and probably most, if not all, of our readers will agree with that. But let us take a look at the subject. The easiest situation...

Hydrophilic Emulsifier Concentration

Hydrophilic Emulsifier Concentration This subject comes up from time to time and it is time to discuss it again. The hydrophilic emulsifier is used in method D post emulsifiable penetrant inspection. It is supplied as a concentrate, and needs to be diluted with water. This is where problems can arise. Met-L-Chek E-58D was qualified and listed on the QPL at a concentration...

Flash Point vs Auto-Ignition Temperature

We have often looked to other NDT practitioners for input for Penetrant Professor articles. In this case we are basing the article on the newsletter put out by two knowledgeable French friends, Patrick Dubosc and Pierre Chemin. Over the years we have heard these two physical parameters being mixed up by penetrant users. Safety Data Sheets (SDS’s) are often a source for...

Is Water Washable The Same As Water Based?

Is Water Washable The Same As Water Based? We recently had a customer call who was being pressed by an auditor to prove that the level 3 water washable penetrant he was using, (Met-L-Chek FP-923), was not a waterbased penetrant. Being pressed by an auditor is nothing new to hear about but this question came out of left field. It brings up...

What Is The Smallest Crack You Can Find?

What Is The Smallest Crack You Can Find The proof of the pudding that this newsletter is driven by its readers is much more obvious to us than perhaps to the readers. But a sterling example has just occurred, as a reaction to a recent article in the May 2014 PENETRANT PROFESSOR.The reader wrote as follows: “There are many like me who...

Pesky Penetrant Contaminants

Pesky Penetrant Contaminants Although the major components of penetrant inspection products usually cause no problems with the metals with which they contact when used correctly, there are some minor contaminants that can cause problems and which must be limited in certain applications. The  governing specification, SAE AMS 2644E, has taken a broad view of this by requiring that the penetrant materials be...

People Who Really Work at NDT

This issue of the Penetrant Professor is slightly different than earlier issues. Taking a lead from ASNT’s publication “The NDT Technician” and it’s feature “Practitioner Profile”, the professor thought it would be of interest to share an e-mail received from some one who is very into his profession of NDT practitioner. One reason for doing this is that the general focus of...

Can gun light – Labino MB Zeus with Athena attachment for aerosol

Can Gun Light Speaking about battery powered LED UV-A inspection lights, Met-L-Chek has available a clever light that fits on a can gun for aerosol cans. The can gun may be attached to an aerosol can of fluorescent MPI materials such as MPI-1400B, or FP-923 penetrant, or D-70 non-aqueous developer. The light can also be removed from the can gun to be...

What about inspecting equipment used in food preparation?

Met-L-Chek has customers who are in the business of processing food, including many dairies. These customers are regular users of penetrants in the maintenance of their processing equipment. Yet we frequently get questions from others who process food as to whether we have penetrant products that are approved for use in the food industry by the FDA. The answer to this question...

The Business of Running Lab Samples

Which Foot Is The Shoe On? One of the exciting things about being in the business of manufacturing inspection penetrants occurs at the beginning of each month. That is when many penetrant users send in their samples for our Pen-Chek® evaluation, so that they meet the requirements of ASTM E-1417 or another relevant specification. You might wonder how this could be exciting,...