Paint Surface Preparation (for Polishing)

From DetailingWiki

Paint Surface Preparation

• Surface preparation is one of the most important steps when polishing to achieve a flawless finish

• Orbital and dual-action polishers can be safely used by the weekend enthusiast, show car owner or professional detailer without fear of damaging the finish. If you're experienced in machine polishing, our professional rotary polishers will allow you to remove deeper scratches, swirls and paint defects. If you've been detailing your car by hand, consider stepping up to a machine polisher. You can not duplicate the finish obtained using a machine polisher.

• Paint System Thickness- Most modern vehicle paint film systems comprise; Primer coat of 2Mils, Colour coat of 1-2Mils, Clear coat 2-3Mils. Removing more that 0.5 mil 0.0005") of clear coat will cause premature paint film failure. As a point of reference two sheets of Saran wrap placed on top of each other measure 1.5Mil (0.0015") a surface scratch that will `catch' your fingernail is approximately 0.004" deep will usually require wet sanding and refinishing. There comes a point when you must judge wither removing a scratch will compromise the clear coat and if so you’ll have to ‘live’ with the imperfection

• Going through the grits - What does this mean?” Very similar idea to ‘Least aggressive first’ it refers to the process of using different grit finishing papers of progressively finer grit or foam / wool pads with progressively denser pads to get a smooth finish. By going through the grits each progressive piece of grit finishing paper or pad removes the scratches from that previously used. Always start with the least abrasive combination , i.e. a machine polish and the least aggressive foam / wool pad. If that combination doesn't remove the imperfections, using the same machine polish and change to a more aggressive pad, if the surface imperfections remain, then step-up the abrasive polish and use the least next level (abrasive)only when the paint has a consistently level, smooth, satin finish should you continue to the polishing stage.

• The most important first step in the process of paint surface detailing is diagnosing the paint surface; type of clear coat or single stage, paint thickness, composition (hard / soft) surface condition and choice of polish / compound for correction / renovation level required (or possible), correct surface preparation for product(s) used and then applying a suitable glaze, wax or polymer sealant dependant upon level of finish required. No matter what product is used it can only reflect what in underneath it;

• Car wash concentrate- removes dirt / dust / road grime

• Detailer’s clay- removes surface contaminates that cannot be removed by washing

• Prepare paint for polishing, compounding - Hi-Temp's Prep Wash (removes silicone, oils, etc)

* Machine polish abrasion choice is dependant upon condition of paint surface. Always use the least aggressive product first, evaluate the surface, then only if necessary `step-up' to a more abrasive product and / or pad.

• Machine polish 1- heavy abrasives (deep scratches -1,000 grit)

• Machine polish 2- medium abrasives (medium to light scratches -2,000 – 2,500 grit)

• Machine polish 3- light abrasives (light surface imperfections – 2,500 – 3,000 grit)

• Check paint surface - Menzerna Top Inspection or 1:1 solution isopropyl alcohol / distilled water

• Only when the paint has a consistently level, smooth, satin finish should you continue to the polishing stage.

• Final paint surface prep - chemical (solvent) cleaner- to remove any oils / waxes / silicone

* Silicone Removal:

Note: The removal of oils and / or silicone is very important when using Menzerna polishes, Polymers or Zaino showcar products as they all react very negatively to silicone, that’s the reason for its inclusion

• The Removal of Smearing from a polished surface - Polishing is a mechanical process. Silicon is a product that has been designed not to be removed by mechanical abrasion. When using Menzerna, to polish surfaces which have been previously treated with silicon, a smear may result. It is important to understand why this occurs.

• Cause - There are lots of silicon oils on the market. The properties that make silicon so popular with car detailers, and some auto manufacturers, also make it a very difficult product for the polisher to remove. During polishing, the silicon mixes with the excess paint that is being removed from the surface to form a smear.

• Can you remove silicon from a clear coat completely? It is impossible to remove silicon from a painted surface without using a chemical process so aggressive that it dissolves the paint. Wax and grease removers will chemically remove one layer of silicon off at a time but are unable to completely remove all the silicon. Tests by Dr Michael Hauber at Menzerna using a spectroscope showed the layers become thinner but the silicon remains. Removing silicon completely can take place over time and involves a lengthy process of oxygen, chemicals, time and sunlight.

We should differentiate between swirl marks in the silicon layer and swirl marks in the paint underneath. Some polishes may appear to remove the swirl marks in the paint but are really only working on the layer of silicon. So the swirl marks in the paint itself remain unaffected by the polishing and reappear after a few weeks, as the silicon is being removed by time.

* Preparation- If the car has been treated with silicon, use a wax and grease remover to remove as much of the silicon as possible before polishing. You will not be able to remove it all but it helps.

* A mild Chemical process- body shops use Hi-Temp's Prep Wash to cleanse the finish before painting, and you can use it after buffing or levelling applications. It prepares the surface for the proper bonding of waxes, glazes and paint sealants. If this is not done properly, applied products may not bond, which will cause heavy streaking.It may be diluted, but is always used sparingly at any strength. Mist a cloth or sponge and wipe over the surface. Wipe dry with a clean towel. Hi-Temp's Prep Wash - Top of the Line Auto Detailing Supplies.use Hi-Temp's Prep Wash to prepare a paint surface for polishing, compounding, wax and / or polymer sealant application (especially if changing from a wax to a polymer product) this is a water-based paint cleaner designed to remove all traces of silicone, oil, and buffing residue from any exterior paint surface, residue from polishing products accumulate in crevices, around handles, wiper arms, on trim, luggage racks, and aerodynamics. Hi-Temp's Prep Wash flows into these hard-to-reach areas and dissolves the build-up.

• Alternative product - DuPont's PrepSol, Acrysol Silicone Remover

* Polishing - when a silicon-free polish works on the paint surface it uses aluminium oxide particles, suspended in water and hydrocarbons and a mechanical process (polishing) to abrade the paint surface to the base level of the scratch. Silicon cannot be removed by mechanical means; silicone can only be removed with chemicals (solvents). If it is not removed the silicon mixes with the paint dust and polish powder and it creates a smear on the paint.

Information resource -

• “Automotive Detailing Inside & Out, A Knowledge Base for the Perfectionist"– by Jon Miller