Why water beads might be harming your finish

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Sliding angle​

Talking about this concept is contrary to how coating brands frame hydrophobicity. Usually all they’ll mention is contact angle, implying that this metric is the sole determination of water repellency. But contact angle is only a static measure. A dynamic measure like sliding angle is what really tells you how easily a bead can leave your paint.

So what accounts for low sliding angle? There are several metrics at play, but at the most basic level the answer lies in the slickness of your paintwork. The more slick the surface, the more easily a bead can roll off.

"The detailing crowd have really got the terminology confused - beading meaning hydrophobic and sheeting meaning... errrrr... hydrophobic. The worst of it is that many think that the 'sheeting' they are describing is hydrophillic. The problem comes in the 'sheet' definition. A drop of water on a hydrophobic surface forms a 'bead' - all good there. The same droplet on a hydrophilic surface forms a flat sheet (it spreads out flat) - but this isn't what detailers mean by a sheet. In detailing, a sheet is simply a collection of water droplets on a hydrophobic surface but a surface which is not hydrophobic enough to break that sheet up into droplets. In detailing, a bead and a sheet are manifestations of exactly the same surface chemistry.

It has got to the point that some now use the technical, hydrophilic, term to describe the detailers sheet - which is quite the opposite of fact. Worst of all, some of the brands, in a wonderful demonstration of their utter lack of technical expertise, are guilty of this!"

"Believe it or not, contact angle (what makes beads look impressive) and sliding angle (what makes them run off) are quite distinct and not necessarily linked. In fact, many high contact angle surfaces require quite high sliding angles to clear them. In automotive, contact angle is for show, sliding angle is what is actually best."
 
This is the one reason I wish waxes and sealants didn't bead, because rain water sits on the hood of my truck and leaves stains that sometimes need to be polished out. Airborne chemicals and dirt are deposited on the paint when the water evaporates, and that stuff is not fun to get off.
 
Back in the old days, water beads were also considered problematic: it was thought the beads could magnify the effects of sunlight, leaving a permanent scar on the paint. Maybe more of a problem close to the equator…
 
I haven't found any product that will completely repel all water drops off the paint, there isn't one. So the question is, what is worse? Having paint with no protection (no water beads) or paint that has some protection against UV / bird droppings / etc. (with beading).
 
I haven't found any product that will completely repel all water drops off the paint, there isn't one. So the question is, what is worse? Having paint with no protection (no water beads) or paint that has some protection against UV / bird droppings / etc. (with beading).
This exactly. It was always obvious after a rain storm at my work parking lot. My vehicles would have long lasting water beads and all the other cars would be dry soon after. I can honestly say that the paint on my cars always looked almost new for many, many years. I regularly wax them.

My coworker, and most people I know, don’t wax theirs. Here in Texas clear coat will start failing around the 6-7 year mark, if the vehicle is kept outside and not regularly waxed. Which most people don’t.
 
Water beads from a garden hose would have the minerals that cause spots, but most people doing a wash will also dry afterwards. Water beads from rain have very little minerals so few if any spots remain.
The only type of spots I've ever observed were from a hose, which is expected, and small dirty areas where beads had formed. I assume this is from the rain water, which carries dirt. Ideally the bead would encapsulate it and move off the surface. I've noticed that water will move off the surface quicker with some products vs others. This topic is kind of ridiculous, but beading is what most want to see.
 
This exactly. It was always obvious after a rain storm at my work parking lot. My vehicles would have long lasting water beads and all the other cars would be dry soon after. I can honestly say that the paint on my cars always looked almost new for many, many years. I regularly wax them.

My coworker, and most people I know, don’t wax theirs. Here in Texas clear coat will start failing around the 6-7 year mark, if the vehicle is kept outside and not regularly waxed. Which most people don’t.
I'd use a wax with good UV blocker in Texas.
 
My thought is that it doesn’t really matter in the long run. Water that sheets off is preferable to beading but you need a surface that is not horizontal to get that. Until they start making automobiles that look like balls the water spot issue will continue.

Even with sheeting there will be tiny bits of minerals. These are what cause damage to the clearcoat. The sun heats them up and they create a tiny pit for other debris and water to collect. A bead of water will hold the minerals and such and as the sun evaporates the water bead the debris is left to cause damage. Sheeting will remove some of that debris but not all of it.

A regular regimen of a good wash followed by a protective LSP is the best you can do.
 
This exactly. It was always obvious after a rain storm at my work parking lot. My vehicles would have long lasting water beads and all the other cars would be dry soon after. I can honestly say that the paint on my cars always looked almost new for many, many years. I regularly wax them.

My coworker, and most people I know, don’t wax theirs. Here in Texas clear coat will start failing around the 6-7 year mark, if the vehicle is kept outside and not regularly waxed. Which most people don’t.
Exactly. When you see 10+ year old cars that look new you can bet the owner was applying some form of protection over the years. I have one coworker that waxes his vehicles, one. His 13 year old Dodge Chargers paint still looks good and it has been parked outside every day for years. Another coworker has a newer Challenger and it doesn’t receive such care and the clear has failed / is peeling in multiple areas. It seems people that wax / protect their paint are on to something.
 
It makes complete sense that anyone that washes and protects their vehicle will have a better looking vehicle in the long run. It shouldn’t surprise anyone that there are those who never wash their cars. We have plenty of stories here about those who never change their oil. It’s the same mentality.
 
I can see it going both ways TBH. My Elantra was NEVER waxed, until i bought it, and the paint looks amazing. But i also notice water that beads up on the paint, and takes much longer to dry because of the "beads". I could see if you have "dirty" rain or something, water spots appearing because the water sits on the paint for much longer.
Here is my elantra when i first picked it up, after only a power washing. The paint was very "dry" and water did not bead up at all. But it did not have water spots. The 2nd picture is the elantra today, waxed with a synthetic based paste wax, and then finished in ceramic spray on wax. the water beads up beautifully, and just falls off the paint now. no water spots to report.. Even dust, dirt and bugs do not stick to the paint. I'd rather have my paint protected to the max, and maybe have a water spot here or there to worry about, then to have it fade, or feel like sandpaper, and not look good with zero protection..
 

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Self cleaning is a result of beading, surface tension, type of beading, contact, slide angles and paint slickness. "self-cleaning" properties per Griot's - defined by the resistance to soil, grime, oil, alkaline, and acids. So, a ceramic-treated surface sheds these contaminants, or self-cleans, when exposed to rain... keeping your vehicle cleaner longer.

As long as you have something on your paint, and you maintain it, you're good. Product choice is least important IMO.
 
This reminds me of the action I get after I started using the Griots 3 in 1 Ceramic spray. If the car is parked outside in a rain and I drive off after the rain has stopped, all those beads on the hood fly off onto my windshield and beyond once I get to a certain speed. Anyone behind me would get it as well.
 
I’ve blocker is useful everywhere. But the reality of its effectiveness is ??????
It's a good question. One guy over at AG claimed he used Optimum Spray Wax which has patented UV blockers in it and after 14 years the headlights were like new. Claims it worked really well. I have no idea how true that is or how much they work. Most products claim UV protection.
 
It's a good question. One guy over at AG claimed he used Optimum Spray Wax which has patented UV blockers in it and after 14 years the headlights were like new. Claims it worked really well. I have no idea how true that is or how much they work. Most products claim UV protection.
Lots do claim UV (my auto spell check is the worst, not I’ve, lol). I’ve seen tests with a UV source that imply the performance isnt really there. But I have no real way to tell.

Best I can hope for is that claims are true, and whatever I put on helps dirt and dust to shed And not stay on there….
 
Lots do claim UV (my auto spell check is the worst, not I’ve, lol). I’ve seen tests with a UV source that imply the performance isnt really there. But I have no real way to tell.

Best I can hope for is that claims are true, and whatever I put on helps dirt and dust to shed And not stay on there….
Exactly. With detailing products there is really not much to go off of.
 
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