Should I use (Dawn) to wash my paint?

[togwt]

Washing-up Liquids (Detergent)



The use of this type of dish washing detergent has been debated for years among car detailing enthusiasts. Problems arise when people use dish washing liquid as their normal car wash soap. From a chemical standpoint using dishwashing detergents to clean a porous, sensitive clear coat paint surface is very poor choice. Dish washing detergents usually contain a sheeting agent (Alcohol alkoxylate or sodium) or other additive to avoid water spotting; along with emollients or moisturizers; these work by forming a thin protective coating on the surface of the skin to prevent any loss of moisture, this will leave a film on the paint surface. Dawn specifically uses Ethyl Alcohol (Ethanol) as its main cleaning agent



This is in no way a criticism in any way, as most of you do not have chemical backgrounds and have no other way of knowing besides what a marketing team tells you or what manufacturers put on their labels. I`m trying not to turn this into a chemistry lesson; just providing enough chemical information for you to make an informed decision



Notable brands of dishwashing liquid include Procter & Gamble’s Dawn®, which is the leading brand in the United States, and ````` Liquid, which is the bestselling brand in the United Kingdom and similar type dish washing liquids chemistry relies primarily on detergent and surfactant technology. This type of chemistry has advanced to the point that it can be engineered to specific soils (i.e. organic grease)



Detergent and soap chemistry and product formulation is a lot more complicated than this, suffice it to say; modern car wash formulations are automotive soil specific. Almost every manufacturer of detergents uses salt as an ingredient, it increases viscosity making it easier to work with, and it also acts as filler, which lowers first costs. Car wash concentrates don’t formulate their products with salt as it drastically increases corrosion rates



As a means of paint surface preparation and the removal of wax / polymer sealants it’s not very effective as paint protection products are usually formulated to be detergent resistant. It was initially used by body shop detailer’s to remove traces of the oils from waxes commonly used on Nitrocellulose Lacquer paints, this is probably the reason some long established painters recommend its use a paint preparation product prior to using their sealants.



Advanced auto wash concentrates and paint cleaners are available and are better suited to cleaning paint surfaces. Modern clear coat is porous so I would not recommend using a harsh dishwashing detergent such as Dawn® on a regular basis, as they contain both sodium and a degreaser, although most of them are approx pH 8.0 (although pH is not the only thing to consider when evaluating products) the MSDS will provide other relevant information.



The MSDS indicates that this product contains Sodium laureth sulphate a foaming agent, Dodecylbenzene sulphonic acid and sodium hydroxide; these salt crystals could be mildly abrasive when they `come out` of the compound later and will then permeate the pant surface.



Almost every manufacturer of detergents uses sodium as an ingredient, it increases viscosity making it easier to work with, and it also acts as filler, which lowers first costs; the amount used and the dilution ratio (1oz per gallon) 1:128 would render these chemicals (sodium) mostly harmless.



Dish washing detergents usually contain a sheeting agent (Alcohol alkoxylate or sodium) or other additive to avoid water spotting; along with emollients or moisturizers; these work by forming a thin protective coating on the surface of the dishes or glassware and also to protect the skin to prevent any loss of moisture. However emollients make the paint surface more difficult to dry and leave an oily residue on the paint surface, which may negatively affect .product cross-linking / bonding and will also negatively affect the surface reflectivity (Gloss) Dawn specifically uses Ethyl Alcohol (Ethanol) as its main cleaning agent



Emollients have three basic properties:

Occlusion - providing a layer of oil on the surface of the skin to slow water loss and thus increase the moisture content

Humectant - increasing the water-holding capacity of the stratum

Lubrication - adding a slip or glide across the skin.



To remove any reside re-wash the surfaces with a d-limonene based solvent cleaner (P21S Total Auto Wash or Chemical Guys Citrus Wash) this will also remove the emollients (film) left by dish-washing detergents



Generally you should avoid the use of household cleaning products for automotive detailing as they are formulated for an entirely different type of cleaning

.

[Your car surface and the dirt that gets on it are a lot different from the food soils and dishes that dishwashing liquids clean effectively. We don`t recommend them for cleaning your car] Proctor and Gamble



See also FAQ Proctor and Gamble website - FAQ

[Accumulator]

TOGWT- Good on you for using those qualifiers (e.g., "as their normal car wash soap, "on a regular basis", "Generally..").



Oh, and "guess the identity!" :chuckle: with regard to recommendations from painters who now sell sealants

[RaskyR1]

Great post Jon!

[togwt]

Thank you both for the kind words. Dawn washing always seems to attract misinformation

[jfelbab]

One comment (correction?)



Perhaps it was a typo but the MSDS for the DAWN products; Ultra, Ultra Plus and non-Ultra, all list them at a pH of 9 in a 10% solution, which if I recall correctly, is 100 times more alkaline than a base pH 7.



I`m not suggesting that auto paint is terribly sensitive to a pH value of 9 but the same may not be true for vinyl, plastics and moldings especially if they are aging, no? I recall reading a paper on how vinyl, in particular, doesn`t do well in higher alkaline environments but can`t place it now.



Your thoughts on this?

[togwt]

A pH value of 9.0 is alkaline, but then most car wash concentrates are pH 8-9.0.



A high alkali would negatively impact vinyl by drying the plasticizers, but I would think this would be true of higher (base) pH values. Having said that there are other things to consider when selecting a cleaning product other then its pH value ( Brighteners (Z)-Stilbene, emollients, etc)



IMO many car care product mfgs use pH values as a smoke screen to take attention away from other chemicals in their product formulation i.e. it has a pH of 7.5 so it must be safe.



A products pH value is important, but there are other chemicals used in a formula that can buffer (`control` by adjusting) the pH values

[David Fermani]

I`ve been using Dawn exclusively on my car for nearly 20 months and have had zero issues with my paint or trim. Keep in mind that I live in Florida and the car is not garaged. I also leave the heavy concentration on my paint to bake in the sun for extended periods of time as it is mitigates water spots. I seriously doubt Dawn can damage paint or attack the plasticizers in stable exterior trim. There has been countless speculation and wivestales about this damage with zero proof to document the arguement. If someone can show my one iota of proof I and the rest of the detailing world would appreciate it.

[Bill D]

I personally never felt the need to wash with Dawn and I haven`t seen any verified and conclusive proof as to its damaging effects on automotive surfaces- but I also doubt any testing has been conducted. It remains a judgement call. I just stick with products made for cars myself. I don`t where Bud has been lately on the forum but here`s an article he wrote on the subject:





Washing a car with`dishsoap - Auto Detailing Industry Information by Bud Abraham - Car Detailing Business Resources

[David Fermani]

The biggest reason I`ve been using it on my car is to try to kill Opti-Coat(which it hasn`t). http://www.autopia.org/forum/car-det...st-review.html Otherwise, I use it after polishing and prior to sealing. I`ve read Bud`s article as well and will throw that one onto the pile of wivestales too. :tongue1:

[Bill D]

The biggest reason I`ve been using it on my car is to try to kill Opti-Coat(which it hasn`t).

Hmm.. I`m wondering if a solvent like Prep-Sol or similar will kill it. If not, sounds like strictly polishing it off is the only way.

[David Fermani]

I use Goof Off on the lowers to clean off tar, but that doesn`t seem to have disturbed the coating so far.

[Ben@3D]

A nice splash of acid will do the trick. :madgrin:

[David Fermani]

I`d try it if you guys could ship some?? :sadpace:

[Bill D]

If you mean Prep-Sol, I would if I had some. Actually for the first time, I finally saw a site that has it. It`s on my "possibly to pick up in the future" list.

[Accumulator]

A nice splash of acid will do the trick. :madgrin:

While I bet you`re being a bit facetious, I do wonder how something like AI/VG`s "B" would work for that :think: