Coating process
In the painting process the bodyshell is dipped and:
- Alkaline-cleaned
- Phosphated (roughening of the surface so the coating forms a good key) and
- Cathodic-dip coated (anticorrosion coating that coats the insides of all body cavities).
The organic paint coat is then baked on.
In follow-up processes the body is sealed with PVC and protected by filler and topcoat paints on the outer skin.
Critical parts of the body of the F01/F02 are specially treated with cavity sealant.
The objectives are:
- 3 years without any visible corrosion whatsoever
- 12 years without rust penetration
- High level of seal efficiency against increase of water and dust.
The design implements the following measures aimed at controlling acoustic effects and vibrations in the F01/F02 bodyshell:
- Narrow engine-mount base to reduce structure-borne sound transmission to the front of the car
- Longer rear-axle mount base; solution of the trade-off between liveliness of response on the one hand and acoustics on the other
- Rolling acoustics with runflat tires on a par with those of non-runflats
- Optimized vehicle insulation, even though the roof is aluminum
- Double bulkhead panel with need-oriented acoustic insulation
- High static and dynamic body stiffnesses; homogeneous flex line
- Outstanding idling comfort
- Acoustically insulating glass available as an optional extra
- V8 and larger engines: hydraulically damped gearbox mounts:
solution of trade-off between shake vs. acoustics.
Separating the roof from the bodyshell
The aluminum roof is one of the engineering highlights of the F01/F02 bodyshell.
- Aluminum roof on steel body in series production
- Weight saving (8.4 kg for the slide/tilt sunroof version)
- Lowers the car's center of gravity > drive dynamics, CO2
- Adhesive-bonded aluminum roof; this also means optimum anti-corrosion protection in mixed-material construct
- Top part of frame riveted (slide/tilt sunroof version)
- Patented shaping to compensate for thermal expansion and contraction
- Use of a newly developed adhesive generation ("expansion/contraction vs. strength", shear modulus over temperature, long-term strength)
- Spacer nubs integrated into roof ensure correct gap for the adhesive
- Assurance of a roof-rack concept (100 kg load-bearing capacity).
The aluminum roof can be separated from the bodyshell by heating the adhesive and inserting wooden wedges to open a gap between the aluminum roof and the bodyshell.
Separating roof from bodyshell