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July 05, 2023

Pecora Fluid Applied Wall Coating & Primer All Field Test Procedures

The following field test procedures are recommended to evaluate the adhesion of Pecora’s fluid applied wall coatings when in-service or a component of a pre-construction mockup. Both qualitative and quantitative methods are listed below. Quantitative field adhesion test methods are preferred or required for warranty purposes. All field test results must be documented and submitted to Pecora Technical Service for review. Photos and/or videos of the field testing are encouraged.

QUANTITATIVE Test Methods – ASTM D4541 Pull Off Adhesion Strength (Modified)

The purpose of this test is to quantify the adhesive strength of a coating to determine whether the installation has been completed properly and acceptable adhesion is achieved. Release or separation during the test will occur along the weakest part of the material or bond between the material and the substrate. Poor adhesion may be caused by poor substrate preparation, partially cured coating and/or improper coating application. The modified field adhesion test method presented here is based on the methods published in ASTM D4541 Standard Test Method for Pull Off Adhesion Strength of Coatings Using a Portable Adhesion Tester.

Items required for modified test procedure:

  • High Strength Magnet (minimum 50lb pull) with eye bolt
  • Luggage Scale with carabiner or locking clip (minimum 50lbs capacity)
  • Steel Coupons (aka test dolly); white metal finish & 1in2 surface area
  • Test Dolly Adhesive (refer to Table #2)
  • Flat Blade Caulking Knife, Razor Knife
  • Bulk Caulking Gun, Plastic Nozzle

ASTM D4541 (Modified) Test Preparation:

  • Attach a steel test dolly to the fluid applied coating material to be evaluated using a non-sag type liquid adhesive. Maintain adhesive thickness at 1/16” to 1/8”. Refer to the table #1 for Pecora recommended test dolly adhesives.
  • All fluid applied coatings should be fully cured per the manufacturer’s instructions prior to attaching the test dollies. Be aware that attaching a test dolly to a partially cured coating may retard the cure and negatively affect the test results.
  • Allow test dolly adhesive to fully cure per the recommendations in Table #1 prior to performing the testing. Do not disturb the test dolly during the specified cure period.

Quantitative Test Methods – ASTM D4541 Pull Off Adhesion Strength (Modified) cont.

ASTM D4541 Test Procedure (Modified):

  1. Locate a 6” x 6” unobstructed area to perform the adhesion test. Testing should be completed on each type of substrate coated with a Pecora fluid applied coating/primer.
  2. Clean the test area with a solvent wipe (isopropyl or denatured alcohol preferred) and allow to dry.
  3. Apply a small dollop of Pecora XL-Flash to the surface that will allow full embedment of the steel coupon. See Photo #1.
  4. Apply the 1” x 1” steel coupon firmly into the wet XL-Flash allowing for slight squeeze out. Immediately remove excess squeeze out (see Photo #2). Allow for an approximately 1/8” thick film of adhesive between the substrate and coupon.
  5. Allow the XL-Flash to fully cure. Low ambient temperatures (<50F) will extend the cure time. 6. Lightly score around the entire perimeter of the steel coupon down to substrate. See Photo #3. a. If applied over an exterior grade gypsum sheathing substrate avoid cutting into the gypsum core. 7. Attach the magnet centered on the coupon. 8. Attach the scale to eyelet and begin the test by pulling the scale at a slow and steady rate until failure occurs or a designated minimum value is achieved. Refer to Table #3 for minimum values per product. Once the test is complete, you will need to record maximum pounds-force achieved, the type of release, the surface in which the release occurred, and the percentage of release on each surface. This information should be noted in the test log. NOTE: ASTM D4541 Pull Off Adhesion Strength testing performed with Elcometers or comparable portable testers are also acceptable for warranty purposes. Refer to the test device manufacturer’s guidelines or consult Pecora Technical Service for test procedures. ><50F) will extend the cure time.
  6. Lightly score around the entire perimeter of the steel coupon down to substrate. See Photo #3. a. If applied over an exterior grade gypsum sheathing substrate avoid cutting into the gypsum core.
  7. Attach the magnet centered on the coupon.
  8. Attach the scale to eyelet and begin the test by pulling the scale at a slow and steady rate until failure occurs or a designated minimum value is achieved. Refer to Table #3 for minimum values per product.

Once the test is complete, you will need to record maximum pounds-force achieved, the type of release, the surface in which the release occurred, and the percentage of release on each surface. This information should be noted in the test log.

NOTE: ASTM D4541 Pull Off Adhesion Strength testing performed with Elcometers or comparable portable testers are also acceptable for warranty purposes. Refer to the test device manufacturer’s guidelines or consult Pecora Technical Service for test procedures.

QUANTITATIVE Test Methods – ASTM C794 Peel Adhesion Strength

The purpose of this test is to quantify the adhesion of a coating via a peel adhesion strength test to determine whether the installation has been completed properly and acceptable adhesion is achieved. Release or separation during the test will occur along the weakest part of the material or bond between the material and the substrate. Poor adhesion may be caused by poor substrate preparation, partially cured coating and/or improper coating application. Minimum peel adhesion strength is 5 pli (pounds per lineal inch).

C794 Test Procedure

  1. Locate a 6” x 6” unobstructed area to perform the adhesion test. Testing should be completed on each type of substrate coated with a Pecora fluid applied coating/primer.
  2. If necessary, clean the test area with a solvent wipe (isopropyl or denatured alcohol preferred) and allow to dry.
  3. Cut 1” x 12” piece of airplane cloth (Grade A / FAA-TSO-0158). ***Pecora Technical Service can provide samples of airplane cloth upon request*** a. SilcoPrime: Apply exterior coating over existing silicone coating primed with SilcoPrime per manufacturer’s instructions to create a 2” x 6” test area. b. Air Barrier and WeatherClad: Apply coatings directly over the substrate to create a 2” x 6” test area.
  4. Embed the airplane cloth by immediately placing the cloth directly over the newly applied coating and lightly press into place taking care not to displace the underlying coating.
  5. Apply a small amount of coating over the airplane cloth to fully encapsulate. Refer to adjacent photo of assembled peel adhesion field test sample with airplane cloth.
  6. Allow coating to fully cure per manufacturer’s guidelines.
  7. Attach a (luggage/fish) scale to the exposed airplane cloth tab and peel the tab back at an 180° angle by applying slow and steady pressure. A minimum 5pli is required for warranty purposes. Adhesive failure of the coating prior to achieving 5pli is considered a failing result.
  8. Record test results and submit to your local Pecora field representative and/or Pecora Technical Service Group.

QUALITATIVE Test Method – ASTM D3359 Measuring Coating Adhesion by Tape, Method A (X-Cut)

In the event quantitative pull off adhesion testing is unable to be performed as described above, a qualitative coating adhesion evaluation may be performed via the ASTM D3359, Method A (X-cut) procedure. This test method will assess the coating’s adhesive performance by applying and removing a pressure-sensitive tape over cuts made in the coating. Tape should be 1.0” wide semi-transparent pressure sensitive tape. Consult Pecora Technical Services for acceptable tapes.

Procedure:

  1. Select test area that is free of defects. Ensure test area is clean, dry and coating is fully cured.
  2. Make “X” cut with a razor knife. Each cut should be ~1.5” in length that intersect at an angle between 30° and 45°. Cut through the coating down to the underlying substrate.
  3. Apply a fresh lap of tape over the “X” cut. Place the tape directly over the center of the “X”.
  4. Firmly press the tape with finger to ensure intimate contact with the coating. a. Note: Areas that are not well adhered will be visible through the semi-transparent tape. Rubbing a pencil eraser over the tape test area is good practice and will ensure the tape is well adhered to the underlying coating surface.
  5. Remove the tape within one minute by pulling off rapidly upon itself at a 180° angle.
  6. Inspect the test area for coating removal from substrate. No peeling or removal of coating is preferred. a. Classify each test result per Table #4. See below.
  7. Report the number of tests and locations.

***Pass Criteria: A result of 4A or better is required for warranty purposes***

For more information on our fluid applied wall coatings, please visit our website www.pecora.com. To speak with someone from our expert team of highly qualified Technical Services Group, please email techservices@pecora.com or by phone at (800) 523-6688. Our Technical Services staff offers training in product technology and use and provides the technical assistance you require in the planning and implementation of your project.

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