DIY Network

1938 Packard: Paint Sanding and Polishing From "Classic Car Restoration" episode DCR-409

In this episode, host Mark Lambert undertakes some of the cosmetic restorations on the 1938 Packard.

In this episode of DIY's Classic Car Restoration, host Mark Lambert addresses the cosmetics of our 1938 Packard, showing how to color-sand and polish the exterior paint.

Materials used in this episode:

Standard automotive tools (socket-wrenches, screwdrivers, nut-drivers, etc.)
Polishing compounds
Extra-fine (2500-grit) sandpaper
Spray bottle with water
Soap solution
Rotary buffing/polishing tool
Wool pads
Car-washing supplies
Water-blade drying tool
Lint-free towels
Eye protection

Note: This is a summary of steps included in the automotive restoration procedures shown in this episode of Classic Car Restoration. These are general guidelines for restoration procedures on this particular make and model of vehicle, and for the level of restoration selected for this project. There may be variations in procedures depending model, condition of vehicle, level of restoration undertaken and the types of replacement parts or upgrade kits selected. Always follow proper safety precautions, and read and follow manufacturer's guidelines, diagrams and safety notices that come with any replacement parts or kit that you select.

Safety Alert: Always wear eye protection when working with power tools or pneumatic tools.

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Wet-Sanding and Polishing Techniques

• Since we were able to restore and finesse the existing paint finish on our Packard, rather than having to start with a new professional paint jobs, there are two main stages to the exterior color-restoration process: sanding and polishing. We begin the process with sanding (figure A), using ultra-fine (2500-grit or above) sandpaper. We keep the surface and sandpaper wet using a spray-bottle filled with water, with just a couple of drops of soap added.

• This careful sanding process is critical since it removes oxidation on the old finish that could not be removed simply by washing.

• After gently sanding in one direction on a small area of the surface, inspect the surface of the sandpaper. The fact that our sandpaper remained clear even after sanding (figure B) was indicative that our car had a more modern base-coat/clear-coat paint job. Paint jobs from earlier years were single-stage processes, and these would leave residual paint-color on the sandpaper. With either type of paint job, it's critical to sand gently and avoid over-sanding and breaking all the way through the top layer.

  Figure A

  Figure B

  
  

  Figure C

  
  

• An automatic-feed sanding block (figure C) is ideal for this process. The sanding block is connected to a water supply, and clean water is continuously fed to the sanding surface. This tool is particularly useful on flat surfaces on the vehicle. We loaded this block with 2500-grit sandpaper as well. As before, work slowly and carefully, and sand in one direction.

• Rinse the area thoroughly, and remove excess water with a water-blade, then inspect your work. This will give you an idea of the extent and uniformity of sanding, and whether more sanding will be required.
  

  
  

• Once the sanding phase is done, you can move on to polishing. Restoration-quality polishing compounds (figure D) come in varying abrasion levels -- much like sandpaper. If you have heavy oxidation on your vehicle, you'll need to start with a coarser, more abrasive compound and then move on to finer compounds.

• Since our Packard only had moderate amounts of oxidation, we were able to start with the ultra-fine renovator compound (figure E).

  Figure D

  Figure E

  
  

  
  

• We began polishing using a coarse foam pad installed on our rotary buffing tool (figure F).

• Moisten the surface of the pad, as well as the vehicle surface where you'll be working, with the mild soap-and-water spray solution.

• Apply a dime-sized amount of compound to the foam pad (figure G).

  Figure F

  Figure G

  
  

  
  

• Spread the renovator on the work surface, then begin polishing the area slowly. Gradually increase your speed as you continue polishing (figures H and I).

• Check your progress frequently. Once you've achieved a sheen on the surface, you can move on to a fine pad and finish polish.

• Allow the finish polish to haze over, then buff it out by hand with a soft buffing cloth. Avoid using a rotary buffer for this step as this may leave undesirable swirls on the paint finish.

  Figure I

  Figure H