Adhesive Testing

Owned by Kyle Justin Lacson (Deactivated)
Last updated: May 31, 2021
2 min read

 

Introduction:

There will be some tests that require using an adhesive rather than a mechanical fastener to combine two or more things together. Some joints will be fixated using an adhesive but need to follow a strict protocol when applying it, and for it to take full effectiveness. The two joints that we are concerned about in consideration of Adhesive Testing are the Butt Joints and the Lap Shear Adhesion.

Note: The material consists of a 6oz twill carbon fiber (2 layers), 9.5mm divinycell foam core and another 2 layers of carbon fiber.

Figure below shows a rough sketch on what a single lap shear adhesion looks like. (One material is stacked onto another)

Figure below shows a rough sketch on what a butt joint looks like: (The adhesive is placed on both faces of the material)

Adhesive Used: DP420 NS Black

All 3M brand structural adhesives provide at least 1000 psi of overlap shear strength

  • Replaces mechanical fasteners such as screws, bolts, studs.

  • Can withstand baking temperatures of up to 400 degrees Fahrenheit for 30 min

  • Works on a variety of surfaces: metals, ceramics, woods, many plastics, and glass

  • Adhesive reaches a handling strength in approximately 2hours, and is fully cured in 24h at 72 degrees Fahrenheit/ 22 degrees Celsius.

Note:

Curing: chemical process in which adhesives crystallizes completely, and the adhesive retains its final intended properties that builds up its strength. When adhesive is fully cured, the chemical forms a strong intermolecular bond.

DP420NS Black

Advantages:

  • Epoxy adhesive usually have the highest strength and overall performance

  • Excellent environmental resistance

  • High impact strength

  • Excellent Fatigue Performance

  • 20 min open time

Disadvantages:

  • Usually require a bit of preparation for surface it is to be placed on. Requires a clean and abraded surface to obtain its max strength

Alternative Option: DP6310NS

Advantages:

  • Good strength to performance

  • Quite flexible in distributing the different loads

  • Little to no surface preparations needed

  • 10 min open time

Disadvantages:

  • Reduced strength in high temperatures. (Baking)

Figure below is a helpful chart in determining which adhesive works best with different types of materials

Link here directs you to a pdf file where you can download their brochure for more info:

https://www.3mcanada.ca/3M/en_CA/bonding-and-assembly-ca/composite-bonding/