Fiat 500 Collision Awareness Manual page 33

2012 FF
NOTE: Structural adhesives that meet Chrysler Group LLC's approved replacement materials specifications
include ­ Mopar #05083855AA, Fusor 112B and 3M 08116
Adhesive Types:
• Acrylic Adhesives ­ Bond all types of bare metals and are excellent for cross bonding aluminum to steel. They
have good NVH (Noise Vibration Harshness) properties and some offer anti­corrosion properties, so primers on bare
metals are not necessary. Most acrylics have a fast room temperature cure, and are stable with regards to temperature
and moisture during cure. However, both of these can effect shelf life. Mix ratio is modestly important although the
performance properties can vary with a change in mix ratio. Acrylics are the most forgiving of the three chemistries
with regards to mix ratio accuracy.
• Epoxy Adhesives ­ Bond well to ridged and semi ridged plastics and are generally easy to sand and feather edge.
Some may be too ridged for flexible substrates and they often require primers on bare metal applications. Epoxies
can be heat cured to increase strength and accelerate the curing process. They have a long and stable shelf life.
The mix ratio can vary by ± 50% and still cure. However, the performance properties will vary when the mix ratio is
incorrect. Epoxies are more forgiving than urethanes with regards to mix ratio accuracy.
• Urethane Adhesive ­ Typically flexible and bond well to plastics. However, they usually require primers on metal
surfaces to protect against corrosion. Urethanes have good seam sealing and NVH qualities and are frequently the
optimal choice for seam sealers. They are sensitive to moisture during cure, packaging and storage. Single com­
ponent urethanes usually have a much shorter shelf life than two component urethanes. Mix ratios are critical for
urethanes. In most cases it cannot vary more than ± 5%. Therefore, hand mixing is not recommended. Urethanes
are the most unforgiving of the three chemistries with regards to mix ratio accuracy.
JOINT AND REPAIR TYPES
Body Side Aperture / Quarter Panel
Metal Fatigue/Stress Cracks
Backer Panel Joint
Overview: Backer panel procedures may be used to achieve a smooth joint between panel sections. The backer panel
works well in areas where there is not enough room to smooth or feather in an overlap joint. The backer panel joint is a
common repair for rocker panels, quarter panels and body side apertures.
NOTE: OEM panel replacement such as a quarter panel, side aperture and rocker panel will always require the
weld bonding procedure at the pinch weld flange area(s).
Preparation:
NOTE: Be certain vehicle is evenly supported at normal suspension points.
1. Restore structural dimensions as well as all related mating flanges.
NOTE: It will be difficult to abrade the underside mating surface of the original panel, however this is an impor­
tant step and should be done effectively.
2. Create a 50mm. (2in.) backer panel out of an unused portion of original or new sheetmetal panel, whichever contains
the appropriate shape. Be certain it has a precise fit to the back of the panels it will join.
3. All paint, primer, adhesive and any other corrosion protective coatings must be removed from the mating surfaces
as well as the backer panels themselves, prior to application of adhesive. Grind a 25mm. (1in.) contact area on all
panels where backer panel bonding will take place. The metal should be completely bare and shiny in appearance,
if the metal appears pewter in color all of the galvanized coating has not been removed.
4. Pre­fit the backer panel to the panel(s) being joined, to ensure proper fit. If screws will be used to hold the panels in
place during curing, dry fit them now to be certain of proper fit later. There should be a 0.8 ­ 1.6mm. (1/32 ­ 1/16in.)
gap between the two outer panels, no gap on backer panels.
5. Without a mixing tip attached, purge a small amount of structural adhesive from the cartridge. This will ensure an
even flow of both components.
6. Attach a mixing tip and dispense a mixing tube's length of adhesive from the cartridge.
Application:
Backer Panel Joint
Door Skin
COLLISION INFORMATION
REFERENCE
Backer Panel Joint
Door Skin Replacement
Side Aperture / Quarter Panel
Metal Fatigue/Stress Crack
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