Field Adhesion Testing

PROSOCO’s Shawn Desrosier explains a field adhesion testing method to evaluate the adhesion compatibility of two different materials. The simple tool, a modified digital scale that can be made with items

found at your local hardware store, easily provides an answer to the general contractor, consultant or others on the jobsite with adhesion compatibility questions.

Digital Field Adhesion Tester Parts List

  • Digital luggage scale (100 pound rated) from Bed Bath & Beyond
  • Super magnet (45 pound rated) from Home Depot
  • Stainless steel split ring (100 pound rated) from Bass Pro Shop
  • 1 ¼” x 3/16” Fender washer from Home Depot, purchasable in boxes of 100
  • Loctite Super Glue from Home Depot

Digital Field Adhesion Instructions

Summary: A luggage scale with attached magnet is connected to a washer that is glued to the material to be tested.

  1. Ensure the surface to be tested is free of dirt and debris. If necessary, wipe the surface with rubbing alcohol (IPA) to remove surface contaminants. Allow the surface to dry.

  2. Glue the 1-1/4" x 3/16" washer to the membrane to be tested using Loctite Super Glue. Use sufficient glue on the washer, so when the washer is pressed against the flashing or air barrier membrane, glue spreads over the entire surface area of the washer’s bond side. Avoid excessive leakage of glue outside and inside the washer.


  3. Use a pin, nail, screw or duct tape to hold the washer on the wall during cure. Allow the glue to cure for 30 minutes.


  4. Use a knife to cut around the washer through the flashing or air barrier membrane being tested. Do not cut into the underlying substrate.


  5. Grasp the luggage scale with both hands, similar to holding a computer game controller.


  6. Free one hand, and place the magnet now attached to the luggage scale onto the washer. Return your free hand to the luggage scale.


  7. To avoid injury, DO NOT PULL directly with your arms. Instead, place the outside edge of your hands against the test surface. Grasping the luggage scale between your thumbs and index fingers, twist your hands outward slowly to create a pulling pressure on the magnet and washer.


  8. As soon as the scale reads 20 or over, hold the pull for three seconds until the scale beeps. The word “Hold” will appear as the scale locks in the pounds reading. With a 1-1/4" x 3/16" washer, the math works out to require a pull to 20 to demonstrate 16 psi, the standard set by the Air Barrier Association of America.


  9. Make a record of the reading. Slide the magnet off the washer.
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