Is Silicone bad for paint?
04-01-2009, 06:08 AM
Automotive paints utilizing modern paint technology using water-based high solid/low solvent urethane that for environmental reasons (low volatile organic compounds (VOC)) produce a much softer and more porous finish; its molecules are not tightly linked together as t has a chain-link type structure, which makes it more porous than acrylic or oil based high solvent content paint systems. For this reason you should be cautious as to what chemicals are allowed to come into contact with the paint surface
Silicone [: are polymers that include silicon together with carbon, hydrogen, oxygen, and sometimes other chemical elements]
The Removal of Silicone - 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 a silicone-based product, 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].
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.
Polishing is a mechanical process. When a silicon-free polish works on the surface of paint it uses aluminium oxide spheres, suspended in water and hydrocarbons and a mechanical process to abrade the surface of the paint down to the level of the bottom of the scratch.
Silicon cannot be removed this way. Silicon is removed by a chemical means and is designed to resist being removed by mechanical means. Instead the silicon mixes with the blend of paint dust and polish powder and it creates a smear on the paint.
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.
A mild Chemical process - 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.
Prep Wash can be used 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.
Alternative product ?
DuPont's PrepSol or Acrysol Silicone Remover
See also "Silicone" TOGWT? Series of Detailing Articles, by Jon Miller, one of a series of in-depth detailing articles
04-01-2009, 06:56 AM
Great info Jon!
It should be noted that most (if not all) LSP's contain some trace amount of silicone. I have been told that some of the most expensive waxes in the world contain as much as seven percent.
04-01-2009, 09:30 AM
The solvents and oils (silicone, montan, mineral, etc) that are formulated in an emulsion type carrier system soften the wax, without which it would remain rock hard; the solvents along with oils also allow the wax to spread evenly on the paint surface. The solvent permeates the micro-fissures of the paint surface providing an anchor, as a wax doesn?t form a monocular bond with paint like a polymer, it initially adheres to the paint via surface tension.
Silicon-based products can also have a negative effect on the surface / polish lubrication oils used causing surface smearing. As a polish or a compound uses either oil, wax or a polymer as a lubricant the water content of a quick detailer (80 ? 90%) is not miscible and therefore acts as a buffer between the pad and the polish negatively affecting the abrasive abilities of both diminishing and non-diminishing abrasives
04-01-2009, 12:46 PM
Does silicone bead water? I've come across certain vehicles that beaded water so much that I had to literally sand them with 4000 grit sandpaper & APC/Solvent to break it down for proper surface prep.
04-01-2009, 01:20 PM
Does silicone bead water?
Yes, Silicone has a very high surface tension and is not miscible with water (unless you make it into an emulsion) so it tends to 'bead' water more than other polymers / oils
04-01-2009, 05:31 PM
David, I wonder how an agressive clay (red Meguiar's clay for instance) would work with a mixture of quick detailer and APC/Solvent versus the 4000 grit?
Originally Posted by David Fermani
I have used 4000 grit for removing overspray, and know on the majority of finishes, it doesn't really mar...I'm just thinking out loud here on the clay deal.
Finance during the week, finishes on the weekends.
04-01-2009, 07:18 PM
The solvent would eat up the clay. I think sanding does more leveling of contaminants than clay. I've never experienced a problem that clay could remove that 4000 couldn't. Clay's a nice 1st approach(especially on light contaminants), but 4000 grit will do it better and faster with minimal marring.
Originally Posted by weekendwarrior
04-01-2009, 11:26 PM
Great information guys........Thanks.
04-02-2009, 03:15 PM
I use a couple of tire dressings that if the wind is blowing - causes tiny little spots on the paint, kinda like 3M's Ultrafina - I always use a strong QD to wipe these off ASAP, I wonder if they come back to bite me the next time I detail that car? But, I don't know if they are silicon, but with my luck.......
04-03-2009, 04:48 AM
Water-based silicone dressings - usually a milky-white liquid, Polydimethylsiloxane (PDS) that doesn?t contain petroleum distillate solvents
Solvent-based silicone dressings - Dimethalsilicone (DMS) usually a clear greasy liquid, which leaves a never-dry gloss film, most contain petroleum distillate solvents.
See also "Silicone" & "Tyre_Cleaning-Care" detailing articles series
04-04-2009, 09:01 AM
Great info, thanks. I love the science discussions as they help me understand what is actually happening in certain applications.
04-04-2009, 10:04 AM
Try using Hi-Tech Body Sponge? (Abrasive rating - 6/6) most organic solvents I've used it with don't negativly effect it
Originally Posted by weekendwarrior
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