Beading after adhesive remover and alcohol?

K

ktlimq

New member
In short, I wiped my hood with



3M Adhesive & Wax Remover



a few days ago,



and with



70% isopropyl alcohol the next day.



When it rained yesterday, the water beading on my hood was as good as if the hood had been waxed.



Since the last waxing in December 2008, I noticed that the beading was becoming worse recently. After wiping with 3M Adhesive & Wax Remover and alcolol, however, the beading seems to be restored.



Strange!
 
Did you polish first and then use the solvent or simply strip the surface? Smoothing the surface via polishing would alter surface tension characteristics leading to beads.
 
Could quite possibly be some silicone remaining on the surface. Use more adhesive remover/paint prep. A leveled surface, even though it is smoother, still shouldn't bead. It should have an obvious sheeting action.



This is why I believe that there is silicone from some type of LSP remaining on the surface.
 
etml12 said:
Did you polish first and then use the solvent or simply strip the surface? Smoothing the surface via polishing would alter surface tension characteristics leading to beads.
Click to expand...



Not really, since its an electrostatic interaction between the water and the paint surface. A rough surface simply has more surface area for this interaction to take place.
 
Brand new cars with no protection(with a cleaned surface) bead pretty good. Surface tension will affect beading and there could have been protectants in the car wash soap that was used prior too that didn't get removed with the solvents used.
 
etml12 said:
Did you polish first and then use the solvent or simply strip the surface?
Click to expand...



I did not polish. I just used the solvent.



The car is 92 MB 300D (actually manufactured in 1991) with 306000 miles on it, and the hood has original factory paint.

I have been applying wax by hand 4~5 times a year for several years.





I wanted to apply touch up paint stick to several rock chips. Instead of spot cleaning with solvent before touch up, I cleaned the whole hood with solvent.
 
This brings up some interesting "science" questions that I am just trying to get my head around. Aside from the presence of some hydrophobic film (mineral oil, wax remnants, polymers from prior products, etc.)



GoudyL said:
Not really, since its an electrostatic interaction between the water and the paint surface. A rough surface simply has more surface area for this interaction to take place.
Click to expand...



Is this always true? Wouldn't it depend upon the topology of the surface in question? In one case, the liquid would interface completely with the roughened surface. At the other extreme, couldn't there exist a topology(ies) that the liquid would have difficulty penetrating the texture of the surface due to forces within the liquid and have a wetting effect?



David Fermani said:
Brand new cars with no protection(with a cleaned surface) bead pretty good. Surface tension will affect beading and there could have been protectants in the car wash soap that was used prior too that didn't get removed with the solvents used.
Click to expand...



My line of thinking was that a well polished surface would approach that of a new car and have the effect described by David. Any polymers/thin films people here that might be able to shed some additional light on this?
 
etml12 said:
This brings up some interesting "science" questions that I am just trying to get my head around. Aside from the presence of some hydrophobic film (mineral oil, wax remnants, polymers from prior products, etc.)



Is this always true? Wouldn't it depend upon the topology of the surface in question? In one case, the liquid would interface completely with the roughened surface. At the other extreme, couldn't there exist a topology(ies) that the liquid would have difficulty penetrating the texture of the surface due to forces within the liquid and have a wetting effect?
Click to expand...



There's two sets of interactions, Water-surface, and water-water. The water surface interaction is a function of how hydrophilic/hydrophobic the surface is, what the waters surface tension is, and how much surface area there is to contact.



Depending on the ratio of the water surface vs water-water interactions, the water will either prefer to interact with itself (forming a bead) or interact with the surface (forming a sheet)



Waxes/polishes/oils tend to form a very smooth "level" surface which is also hydrophobic, and does not carry an electric charge. So that greatly reduces the amount of surface area for the water to interact with.



Any polymers/thin films people here that might be able to shed some additional light on this?
Click to expand...



New cars are usually preped by the dealer and there are various agents in the paint which make it hydrophobic at first.
Click to expand...
 
GoudyL said:
New cars are usually preped by the dealer and there are various agents in the paint which make it hydrophobic at first.
Click to expand...



I've seen many new cars that aren't yet touched by the dealer that bead water.



What agents *in* the paint are you referring to?
 
Leveling agents which help the paint spread better and form an even surface as it is applied. They tend to have very interesting surface chemistries.
 
So you're saying that these "leveling agents" are present at 1st when an OEM finish is new, but then evaporate/fall off some how? I wasn't aware that the chemistry of OEM finishes changed with time? Please explain more.....
 
I don't know how it works, either, but I work in a new car dealership and brand new cars with absolutely nothing on the paint will bead like mad. I've also seen freshly painted cars (less than 6 hours dry) bead water like crazy.
 
David Fermani said:
So you're saying that these "leveling agents" are present at 1st when an OEM finish is new, but then evaporate/fall off some how? I wasn't aware that the chemistry of OEM finishes changed with time? Please explain more.....
Click to expand...



The auto paint is a very complex (And I'm food chemist, so more familiar with food polymers than paints) among the things included in it are various "leveling agents" which help the paint spread into an even layer. These are usually surfactants that have very unusual properties.



They help bridge the gap between molecules of resin while encouraging the rejection of water as the film starts to form. At the same time they should be water soluble to begin with...



Silicone Surface-Active Agents



The Birth Of A Floor Polish



-----

Also lets not forget that there are products like Meg's New Car glaze, and a quick spray of QD/Spray wax never hurt anything :)
 
I'm not quite understanding your statement about "water soluable" / "leveling agents" in respect to automotive OEM finishes and how it affects water beading. This sounds like it has more to do with the actual paint application process while at the factory? Within a week(at most) after being painted/baked, an OEM finish is 100% cured, yet beading can continue for months after that. The crosslinking and outgasing processes are completed by then. What does this (or the 2 links) have anything to do with the way water beads on unprotected/bare paint? One is about Floor Polishes and the other is about Sealants.
 
Why is it that any time water beads on paint with no protection there's got to be some great mystery involved???......:think:



Common sense will tell us that a perfectly clean/smooth surface should naturally bead water. It's not just paint, most surfaces will bead water if perfectly clean/smooth.



As mentioned, new cars will bead like crazy, I've prepped multiple cars straight off the truck with plastics still attached and removed them to wash and they beaded fine.



It's really just all about surface tension.



Josh
 
David Fermani said:
What does this (or the 2 links) have anything to do with the way water beads on unprotected/bare paint? One is about Floor Polishes and the other is about Sealants.
Click to expand...



Both of which relate to the formation of thin protective films? Aka clearcoat?



The point is that the hydrophobic stuff which is embedded within the paint and the smooth surface result in new paint having a hydrophobic surface with few places for the water to attach to. Overtime those things will be leached out, and the paint will develop microscopic imperfections and accumulate hydrophillic surface dirt.



IMHO I'd just take some of that 3M Adhesive remover and pour/apply it to some glass and see if it leaves any residue, after an hour or less.
 
You must log in or register to reply here.
Back
Top