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Use the right tape thickness: The necessary thickness of tape depends on the rigidity of substrates and their flatness

irregularity. While the 3M™ VHB™ Tapes will conform to a certain amount of irregularity, they will not flow to fill gaps between

the materials. For bonding rigid materials with normal flatness, consider use of tapes with thickness of 45 mils (1.1 mm) or

greater. As the substrate flexibility increases thinner tapes can be considered.

Use the right amount of tape: Because 3M™ VHB™ Tapes are viscoelastic by nature their strength and stiffness is a function

of the rate at which they are stressed. They behave stronger with relatively faster rate of stress load (dynamic stresses) and

will tend to show creep behavior with stress load acting over a long period of time (static stresses). As a general rule, for

static

loads, approximately four square inches of tape should be used for each pound of weight to be supported in order to prevent

excessive creep. For

dynamic loads, the dynamic performance characteristics provided on page 4 should be useful, factoring in

the appropriate safety factors.

Allow for thermal expansion/contraction: 3M™ VHB™ Tapes can perform well in applications where two bonded surfaces

may expand and contract differentially. Assuming good adhesion to the substrates, the tapes can typically tolerate differential

movement in the shear plane up to 3 times their thickness.

Bond Flexibility: While an advantage for many applications where allowing differential movement is a benefit, the tape bonds

are typically more flexible than alternative bonding methods. Suitable design modifications or periodic use of rigid fasteners or

adhesives may be needed if additional stiffness is required.

Severe Cold Temperature: Applications which require performance at severe cold temperatures must be thoroughly evaluated

by the user if the intended use will subject the tape product to high impact stresses. A technical bulletin “3M™ VHB™ Tape Cold

Temperature Performance” (70-0707-3991-0) is available for additional information.

NOTES: There are a wide variety of formulations, surfaces finishes and surface treatments available on substrate materials which can affect adhesion. This chart is intended

to provide only a rough estimate of the adhesion levels which can be expected on some common materials relative to a reference surface such as aluminum.

Foam type can affect and/or limit maximum adhesive strength.

3M™ VHB™ Tape Specialty Tapes

Design and Tape Selection Considerations

Choose the right tape for the substrate: Adhesives must flow onto the substrate surfaces in order to achieve intimate contact

area and allow the molecular force of attraction to develop. The degree of flow of the adhesive on the substrate is largely

determined by the surface energy of the substrate.

Adhesive

High surface energy

— Substrate

Adhesive

Low surface energy

— Substrate

This illustration demonstrates the effect of surface energy on adhesive interfacial contact. High surface energy materials

draw the adhesive closer for high bond strength.

4950 Family

4945 Family

4910 Family

4951 Family

4952 Family – Adhesion to specific substrates is less dependent on surface energy

4611 Family

4622 Family

1100-400

50-42

39-38

37-36

33-18

Generally good

adhesion

Primer may be

needed for good

adhesion

(High)

(Medium)

(Low)

Surface Energy (Dynes/cm)

Aluminum

Stainless Steel

Copper

Zinc

Tin

Lead

Anodized Aluminum

Glass

Polyimide

Phenolic

Nylon

Alkyd Enamel

Polyester

Epoxy Paint

Polyurethane

ABS

Polycarbonate

PVC

PPE

Acrylic

PU Enamel

Powder Paint

PVA

Polystyrene

Acetal

PVDF Paint

Powder Paint

EVA

Polyethylene

Polypropylene

PVF

Silicone

PTFE

Relationship of Adhesion and Surface Energy for 3M™ VHB™ Tape Adhesive Families