The correct produce for preparation of bare metal is a follows.
Metal must be free of rust and surface oxidization.
Use prep off to remove any oil based contaminates on metal and surrounding paint.
Mask areas of paint not be sprayed ,with metal etching primer,that latter will bond the sharp leading edges of metal in particular.
Apply one think base coat with Priomat 1K washer 4085 Helgrau /Light Grey this is a Mercedes comparable primer as to formulation in both Acyclic and two pack.Spies Hecker
Let dry, apply second misting coat.
Sand off any imperfections use black speckle flat primer as the guide to sand down to a clean Smooth surface.Do not use fingers with with 800=1000 dry Papers or 600 wet.
Use a soft 3M sanding block,not a hard block.
Avoid sand sharp leading edges as to retaining paint primers-micron thickness, where bridging occurs at 90% between horizontal and vertical edging parameters.
Clean pre-prepared primed surface.with prep-off,let solvents dissipate for 5 to 20 minutes depending on temperature.
Apply mist coating of selected paint MB approved, followed by a thicker coating ,spray gun 60 Psi.
If runs are obvious lightly sand with 1200 grit ,clean, and re-spray final coating of paint.
Allow 20 Minutes Dry-Time apply one coat misting of U-POL 20:85 smart clear UV resistant clear coat R-F-U
dry time two minutes,reapply a further two sweep overs of same.
Apply one to two sweeps of Bleeding clear on both new and old clear over coatings.to fuse color match between old and new.
Following day: Use a 1200 rpm RAP150 polisher with a Orange medium cutting pad using FESTOOL No:493 852..Cutting compound: FESTOOL MPA 6000 No: 492 424 or MPA 8000 No: 493 816.
Final polish: Use for small panels less than 1/2 a square meter especially with couture's.
Switch polishing pad to RAP 80 FESTOOL NO 488 337 this pad is soft and flexible waffle in design to penetrate an orange peel surface paint finish such as the TIN to remove Holograms.
Use: FESTOOL Polish MPA 11000 No: 492 437
Final buff with lams wool pads if required or hand buff with a micro pad/2
FESTOOL MPA microfibre No: 493 068
All of the above is what Mercedes-Benz uses for repairs as it is certified By Daimler-Benz
Note: MB Permacoat is a base white series 293;code 9147must be sealed with an over-clear as the paint is porous if not sealed.
9147 paint The Tin series mix is slightly different to the NCV as the TIN is thicker with a more noticeable orange peel paint finish as opposed to the thinner and smoother finish on the NCV, the difference is with hardeners. both paints are otherwise the same.
Richard