Laboratory Testing of Copper Foil

There are many different brands of copper foil available to the stained glass artist today.  Each manufacturer markets their superior performance.  Wouldn’t it be great if we had an independent laboratory perform an adhesion test for each brand? Well, with help from the Georgia Institute of Technology Materials Innovation and Learning Laboratory (MILL), that’s what we did! Read on to learn about the testing method, data collection, and performance summary of four top name brands on the market: Binari, Choice, Edco, and Venture.

Our goal for this test is to complete a side-by-side comparison of each foil manufacturer with regards to adhesion strength.  The Georgia Tech MILL allowed us to eliminate external variables that can affect foil performance. For our purposes we will define adhesion strength as the energy required to propagate delamination (measured in Joules/m2).  In simpler terms, the peel force per surface area (N/m).

Equipment:

  •  Mark-10 F505 mechanical tester 

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  •  G1109 peel fixture 

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Test Environment:

  • Room temp = 22°C
  • Relative humidity = 50%
  • Foil samples = Black backed, 7/32” wide, 1.0mil thick,  Edco, Binari, Choice, and 3M / Venture

Test Procedure:

  1. Clean the test fixture surface with isopropyl alcohol (IPA) and allow it to dry.
  2. Cut each copper foil sample into 10 cm strips.
  3. Attach one end of the foil strip to the tension grip and position the opposite end against the test fixture for a 90° peel test.
  4. Apply uniform pressure of 20 psi to the foil using a J-roller to ensure consistent contact with the test fixture.
  5. Conduct the peel test at a crosshead speed of 50 mm/min using the Mark-10 F505 mechanical tester equipped with the G1109 peel fixture.
  6. Record the peel force and displacement throughout each test and plot force per unit width (N/m) vs displacement (mm).
  7. Determine Interfacial toughness by finding the plateau value using the average of the force/width data from 5 mm displacement to the end of the test.
  8. Calculate interfacial toughness by averaging the force-per-unit-width data from 5 mm displacement to the end of the test, representing the steady-state peeling region.

Important variables:

VariableUnitTest ValueDefinition
Peel ForceNewton (N)Recorded continuous curveThe tensile force measured by the load cell required to continuously peel the copper foil tape off the test fixture
Foil WidthMeter (m)7/32” = 0.00556 mThe width of the copper foil strip being tested, used to normalize force across different tape widths
Foil ThicknessMeter (m)1 mil = .0000254 mThe thickness of the copper foil strip
Foil Backing ColorN/ABlackN/A
DisplacementMillimeter (mm)Recorded continuous curveThe distance travelled by the moving crosshead/tension grip during delamination
Peel speedmm/min50 mm/minThe constant rate of extension at which the mechanical tester pulls the tension grip
 J-roller Application Pressurepsi20 psiThe uniform compressive pressure applied using a J-roller to ensure consistent mechanical bonding before pulling
Ambient Temperature°C22°CThe room temperature of the laboratory environment during testing
Relative Humidity%50%The moisture concentration in the air within the test laboratory
Interfacial Toughness(J/m2) = N/mBinari:175.3 Choice:146.1 Edco:134.5 Venture:132.4The total energy required to propagate delamination per unit surface area. It represents the plateau average of Force/Width from 5mm displacement to the end of the test
Adhesion Strength(J/m2)Binari:175.3 Choice:146.1 Edco:134.5 Venture:132.4Quantified by measuring interfacial toughness

Operation Videos:

Operation Videos:

Data & Analysis:

  • Interfacial Toughness

  • Interfacial Toughness (smoothed) line graph

  • Adhesion strength histogram

    The total energy required to propagate delamination per unit surface area. It represents the plateau average of Force/Width from 5mm displacement to the end of the test.

Performance Summary:

  • Our results reveal that Binari shows the greatest adhesion strength of 175.3 J/m2
  • Choice ranked 2nd followed closely by Edco
  • Venture ranked lowest with adhesion strength of 132.4 J/m2
  • Binari's measured interfacial toughness was approximately 32% higher than Venture's
  • The results establish a performance ranking under the specified laboratory test conditions; however, additional testing may be needed to determine the repeatability and statistical significance of the observed differences.

The results indicate that Binari exhibited the greatest adhesion strength under the test conditions, while Venture exhibited the lowest. Foil age may have influenced the measured values and should be considered when interpreting the results. These findings apply to the specific samples tested and do not necessarily represent the performance of every product offered by each manufacturer.

Thank you Georgia Tech MILL for helping us empirically evaluate our copper foil - GO JACKETS!

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