Seam Sealing

HOW TO: SEAM SEALING

 

Sealing applications in the automotive industry have increased significantly during recent years. Learn everything you need to know about sealing, particularly seam sealing in vehicle body repair, from the use of standard beads to reproduction of OEM textures.
 
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Joining methods

Additional corrosion protection

History of sealing technologies

Seam Sealing: Additional Knowledge

Learn everything you need to know about the subject of seam sealing.

Advantages of adhesive bonds

• Maintain the integrity of the structure
• Transmit loads most evenly
• Spread loads over the entire bond area
• Additional sealing to prevent water and moisture from penetrating between joint parts,which could cause corrosion

Sealants, and seam sealants in particular, must exhibit the following properties:

• Very good adhesion
• High strengh (e.g. for sealing and bonding high-performance components)
• Excellent rust-proofing characteristics
• High flexibility
• Low shrinkage and easy smoothing, particularly on visible seams
• Overpaintable
• Rapid drying and curing

1. Butyl and plastic sealants – non hardening sealants (no structural change after application)

Characteristics:
• Do not harden; retain their plastic properties
• Ideal for interfacing between body-panel lap joints
• High ageing resistance
• Do not become brittle
• Good for shimming
• Excellent water protection

Seam Sealing - Non-hardening sealants technology.

2. Synthetic rubber sealants – physically curable sealants (cured by evaporation of water or organic solvents)

Characteristics:

• Curing occurs through evaporation of the solvents in the product
• Good adhesion, even to slightly dirty, greasy or oily surfaces
• Overpaintable when fully dry
• Resistant to water and salt spray

Seam Sealing - Physically curable sealants technology.

3. Polyurethane (1-component) – chemically curable sealants

Characteristics:

• Cured by absorption of ambient moisture
• Good for sealing and bonding
• Sufficient time for skin formation required before overpainting; suitable for all commonly used paint systems
• Flexible, non-sagging, non-corrosive

4. Silane-modified polymers (1-component) – chemically curable sealants

Characteristics:
• Cured by absorption of ambient moisture
• Excellent for sealing and bonding
• Overpaintable after skin formation with existing paint systems
• Free from isocyanates
• Silicone-free
• Good resistance to UV radiation
• Odour-free

Seam Sealing - Chemically curable sealants technology.

5. Silicones (1-component) – chemically curable sealants

Characteristics:
• Cure by the absorption of ambient moisture
• Elastic sealing (avoided in the body-repair sector)
• Free from isocyanates
• Not overpaintable

Most joining methods must be additionally sealed to avoid corrision caused by environmental factors.

Geometries of sheet metal (spot-welded, riveted or bonded)

Seam Sealing - Sealing of the uneven side.

Sealing of the uneven side,
e.g. door-flange sealing

Seam Sealing - Sealing of the even side.

Sealing of the even side,
e.g. floor-panel sealing

Seam Sealing - Sealing of both sides.

Sealing of both sides

Triple application: L-shaped (right angle), e.g. side- and floor-panel sealing

Seam Sealing - Sealing inside of the application area.

Inside

Seam Sealing - Sealing outside of the application area.

Outside

Seam Sealing - Sealing inside and outside of the application area.

Inside and Outside

Interior applications, e.g.
Passenger compartment floor
Engine compartment
Boot floor
Rear panel
Bonnet and boot lid

Exterior applications, e.g.
Wing
Filler neck
Hem flange
Side panel
Wheel housing
Underbody/sills

Seam Sealing - Seam sealing for interior applications.
Seam Sealing - Seam sealing for interior applications.
Seam Sealing - Seam sealing for exterior applications.