Test Blocks

Magnaflux test blocks allow for the comparing of penetrants used within the LPI inspection process.


Magnaflux provides two test blocks for use in measuring penetrant performance. Our Aluminium Test Block, Part Number 070C001, is used to compare penetrants during the LPI test process. For monitoring the washability of water washable or post emulsified penetrants, the grit blasted finish of our Stainless Steel Test Block, Part Number 154000, may be used.

Aluminium Test Block

The Aluminium Test Block is an aluminium test piece that measures 3” x 2” x 3/8” with a 1/8” wide groove that splits the face in half. The test block is used to check the strength of “in-use” penetrants. This is done by processing one half of the block with “used” penetrant, and the other half with fresh penetrant.


  • Part Number: 070C001 - Aluminum Test Block

Specifications Compliance: Complies with MIL-1-25135.

Stainless Steel Test Block

The stainless steel test block offers a simple and convenient comparator for monitoring washability of water-wash or post-emulsified penetrants.

The “grit blasted” finish provides a rough surface which will retain background when the removability of a product has decreased when compared to fresh material. The test block should be thoroughly cleaned with SKC-S Cleaner/Remover, as well as periodically refinished (grit blast).


  • Part Number: 154400 - Stainless Steel Test Block

Specifications Compliance: Complies with ASTM E165

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Aluminum Test Block







Stainless Steel Test Block