Sealants vs. Structural Metal Adhesives
|
Sealants |
Acrylic Structural Adhesive |
|
Very slow cure rate |
Rapid cure rate |
|
Variable adhesion |
Excellent adhesion to most substrates |
|
Requires surface preparation |
No surface preparation required
(except for corroded aluminum) |
|
Not intended for structural-type applications |
Good choice for structural applications |
|
< 400psi shear strength |
> 2000 psi shear strength |
|
High elongation (100+ %) |
Low elongation (~35%) |
|
One-component |
Two-component |
|
Odorless |
Strong odor |
|
Inexpensive |
More expensive |
|
|
Tapes vs. Structural Metal Adhesives
|
High-Performance Double-Sided Tape |
Acrylic Structural Adhesive |
|
Very poor low temperature performance |
Excellent low temperature performance |
|
<100 psi shear and tensile strength |
Very high strength |
|
Requires careful surface preparation |
Requires no surface preparation* |
|
Poor creep resistance |
Excellent creep resistance |
|
No repositioning once parts are mated |
Mated parts can be repositioned during working time |
|
Expensive |
Less expensive |
|
Instant fixturing strength development |
Good peel strength |
|
Clean application |
Slower strength development |
|
Good peel strength |
Some clean-up required |
|
Good acceptance |
|
|
Distribution established |
|
|
* Except for corroded aluminum |
|
|
Mechanical Fasteners vs. Structural Metal Adhesives
|
Mechanical Fasteners |
Acrylic Structural Adhesive |
|
Each rivet is a stress concentrator |
Evenly ditributes stresses |
|
Can leak |
Acts as sealant |
|
Loosens over time |
Excellent durability |
|
Can cause galvanic corrosion |
Helps prevent corrosion |
|
Difficult to prep around |
No effect on visible surface |
|
Difficult to paint |
No effect on visible surface |
|
Aesthetically unappealing |
No effect on visible surface |
|
Requires hole drilling |
No effect on visible surface |
|
Inspectable |
Not inspectable |
|
Replaceable |
Difficult to remove or replace |
|
|
Welding vs. Structural Metal Adhesives
|
Welding (MIG / spot) |
Structural Adhesives |
|
Creates stress concentrations |
Evenly distributes stresses |
|
Difficult for complex parts |
Ideal for joining complex parts |
|
Creates surface imperfections |
Preserves smooth surfaces |
|
Poor NVH characteristics |
Reduces NVH |
|
Creates corrosion sites |
Helps prevent corrosion |
|
Part warpage (welding heat) |
Does not create warpage |
|
Difficult on thin substrates |
Ideal for thin substrates |
|
High skill level required |
Low skill level required |
|
Often requires post-process finishing |
Very little post finishing |
|
Very rapid strength development |
Slower rate of strength development |
|
High strength |
Strengths can exceed welded designs depending on construction |
|
Highly accepted |
|
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