Author Archives: metlchek

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...

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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...

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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...

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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...

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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....

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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....

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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...

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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...

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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...

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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...

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