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If you are familiar with adhesion testing, you know how important it is to reproduce the area that is pulled. If a technician performed a pull-test without properly defining the area, then the epoxy would seep out from under the pull-stub and would cure to the sample prior to testing. This would result in an effective pull that is larger than 1/2", and the corresponding tensile strength would appear to be higher than it actually is!
At the request of some of our customers we have developed an alternative: the Adhesive Mask. This low tack, donut shaped piece of plastic has a 1" O.D. and a 1/2" I.D and is perfect for adhesion testing.
Instructions For Use:
1.Before testing, place an Adhesive Mask on the sample at the site to be tested.2.Apply your epoxy to the face of a pull-stub and to the center of the Adhesive Mask. The Masks are thick enough that once the pull-stub is applied to the test site at the center of the Mask, it can be slid around until it "locks" into place.3.Once the epoxy has cured, perform your test as usual. Note that these Masks do not need to be removed like the cut-off rings! This is because the low-tack adhesive of the Adhesive Mask has such a low tensile strength that it does not make a measurable difference in a pull test. The larger outer diameter prevents the epoxy from contacting the sample at any location other than the 1/2" where the pull-stub rests.
Try them today!