Good Silicone, not so good Silicone
Silicones are any of a class of chemical compounds consisting of long chains of alternating silicon and oxygen atoms, with two organic radicals, typically a methyl (CH3) and a phenyl (C6H5) group, attached to each silicon atom. Silicones are inert and very stable, they resist the effects of water, heat, and oxidizing agents
- That a product contains hydrocarbon (petroleum distillates) silicone does not necessarily make that product harmful. Silicone is an inert material and is used primarily to modify or improve certain characteristics; they are sometimes added as a lubricant to provide spread ability thereby making a product easier to apply. The automotive industry uses silicones as component parts (see polymerisation) in its plastic, vinyl, rubber, paints, and fiberglass as well as in polishes and waxes.
Understanding dressings is essential; obtaining accurate technical information on automotive care products can be problematic, but detailer’s should be knowledgeable on the dressings sold for tires, rubber, vinyl and leather and their chemical content. Otherwise they are at the mercy of the supplier to provide not only products, but also the technical knowledge and application methodology regarding product usage.
- Unfortunately not all suppliers or distributors have the ability or technical knowledge to provide accurate information to the trade, some do not want to divulge what they term ’trade secrets’ as the information might be detrimental to their product sales or company image. Honest opinion or merely advertising? Commercialism brings with it concerns of honesty and true representation. In other words, it’s difficult to know what is true when someone is motivated by income, i.e. directly targeted at product sales, more so than an unbiased opinion
- Silicones are primarily used to modify or improve certain characteristics; they are sometimes added as a lubricant to provide spread ability thereby making a product easier to apply. The automotive industry uses silicones as component parts (see polymerisation) in its plastic, vinyl, rubber, paints, and fiberglass as well as in polishes and waxes.
Silicone (Siloxane) oils provide an excellent lubricant that when used as a carrier system in polishes and waxes that makes them easier to apply and remove When used in paints and other coatings it ensures an even flow through a spray nozzle ensuring an even product distribution. It not silicone that you need worry about, just the 'type' (what its formulated with) you need to be aware of.
Silicone (Siloxane) oils provide an excellent lubricant that when used as a carrier system in polishes and waxes that makes them easier to apply and remove When used in paints and other coatings it ensures an even flow through a spray nozzle ensuring an even product distribution. Good practice dictates that you perform a wipe-down after paint surface polishing to inspect the surface, (DuPont PrepSol 3919, Menzerna’s Top Inspection or Isopropyl alcohol )dependent upon what product is used, this should remove any silicone
a) Water - based silicone dressings - usually a milky-white liquid, (Polydimethylsiloxane (PDS) that doesn’t contain petroleum distillate solvents that can harm rubber and/or vinyl over time. Water-based dressings use a combination of natural oils and polymers to offer a non-greasy, satin finish.
Some of these products also contain ultra violet radiation (UVR) blocking agents to help keep tires from cracking, fading and hardening. Most, if not all water-based dressings are environmentally friendly / biodegradable, whereas solvent-based silicone is not.
b) Solvent-based silicone dressings - usually a clear greasy liquid, (Dimethal (DMS) that contain petroleum solvents as a cleaning agent, they remove the elasticity from vinyl, rubber and paint; causing them to evaporate out of the substrate, leaving behind a dry inflexible surface. Most high gloss products are based upon DMS silicone oil, the difference between water and solvent based is in the carrier system used. Solvent based products use a hydrocarbon silicone to suspend the product. When you apply it, the solvent evaporates leaving the dressing's active ingredients (Silicone oil) behind; solvent-based silicone are not environmentally friendly / biodegradable
c) Fisheyes: [: Silicone Contamination, Cratering - small circular, crater-like openings that appear during or shortly after the spray application. or wax)
'Paint or Body Shop Safe’(a product that contains no silicone) car care products that are free of ingredients that could cause surface contamination prior to or during the painting operation in a collision repair shop. Silicone is one, water and oil are the other major painting contamination culprits that cause fish eyes, which look like little craters where the paint pulls away from the center, which occurs immediately upon spraying. Fish eyes are caused by contamination of the surface to be sprayed. If the surface to be painted receives the correct preparation it should not cause issues.
Fisheyes’ look like little craters where the paint pulls away from the centre (looks like a fish eye and hence the name)
Cause –* Spraying over surfaces contaminated with oil, wax, silicone, grease, etc.
- Use of thinner/reducer in place of a solvent cleaner.
- Spraying over previously repaired areas containing "fisheye eliminator" additive.
- Once the surface ’fisheyes’, the paint should be polished or cleaned with a chemical cleaner (PrepSol) as something has contaminated the surface. There is no point in sanding down the surface and repainting as the problem will not just go away.
- U.S. Environmental Protection Agency website
- EPA/Purdue University Study 2001
- American Association of Industrial Hygiene (AAIH)
- American Petroleum Institute (API) publications
- National Petrochemical & Refiners Association (NPRA
- Sherwin Williams paint trouble shooting guide
- Automotive Detailing Inside & Out, A Knowledge Base for the Perfectionist– by Jon Miller
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