Weer een leuk stukje tekst gevonden op het DJ forum. Ditmaal gaat het over het begrip Beading
BEADING
There's a lot of love for beading, and with good reason - it looks great and reminds you that your car is protected with wax. However, there are quite a lot of myths and misconceptions to do with beading, so we'll discuss them below. In the meantime, let's kick the thread off with some great beading:
Those tight, upright beads above are caused because the coating the water is sitting on is hydrophobic, ie water hating. Because it repels water, the water droplets try to form themselves into a round sphere - their natural state and shape. The opposite of water hating is water loving, or hydrophilic. These surfaces lower the surface tension of the water bead and cause it to spread out, creating 'sheeting'.
Remember that beading and sheeting is always a surface characteristic of material in terms of water-handling. The water droplet will only react to what it comes into contact with. It does not mean the surface is hydrophobic or hydrophilic all the way through.
MYTH 1) YOU CAN'T HAVE SHEETING AND BEADING TOGETHER
Well, yes, you can. It depends on how water hits the panel as well as the surface characteristics of the coating. If you mist water onto a hydrophobic panel, beads will result. But if you pour water from an open hose, ie you have running water, there will be no droplets formed and the water will run off, ie sheet.
So a hydrophobic surface can bead and sheet.
A hydrophilic surface will sheet.
MYTH 2) BEADING IS A GOOD INDICATION OF WHETHER WAX IS STILL ON THE CAR
OK, here's a picture below of some beading. How much wax is on the surface? Some? A little? A lot?
The answer is actually none, as it has just been machine polished, but you can get great beading on surfaces with NO protection. Perfectly smooth surfaces tend to have high surface tension, so beading occurs naturally (look at glass compared to sandpaper, both are silica materials but one is rough and one is smooth... and beading is better with one rather than the other!). Rough or dirty surfaces will be uneven and disruptive, breaking the lower part of the water bead and allowing it to spread out, due to decreased surface tension.
So good beading could be from:
- A durable hydrophobic coating being present
- A less durable hydrophobic coating being present, like a glaze oil
- A highly polished, smooth surface
And bad beading could be from:
- Dirt or embedded contaminants on the upper surface of a coating
- Microscopic damage ie roughness caused by UV damage, in the coating itself
- A hydrophobic coating having failed
- A hydrophilic coating having been applied to the coating, or at least upper surface of the coating
This is why beading is a poor guide to wax durability. You need to make sure the car is clean before judging the beading, so give it a wash (use a residue free shampoo like Born to be Mild, many shampoos are swimming in silicone which will give a 'false positive'). You need to ensure that hydrophilic - or hydrophobic - products hidden in shampoos and quick detailers have not snuck onto the surface without you realising... how many people wipe down a top wax with a cheap quick detailer without realising what is in the residue? And you also need to realise that because beading is a SURFACE characteristic, that the wax may still be present beneath the uppermost 'non-beading' layer. That's right... the beading will drop off with carnauba waxes after a couple of weeks as the UV degrades it and contaminants embed themselves into the sacrificial layer you have presented... but the wax may still be there, underneath it all, protecting the paint still.
MYTH 3) BEADING ALWAYS LEADS TO WATER MARKS
Beading that is left to evaporate on a car will lead to water marks IF there is contamination (limescale or dirt) in the water. Use a DI resin filter for the final rinse and there will be no issue. But rain water tends to be quite dirty and tap water may contain limescale. You can get watermarks with sheeting hydrophilic products as well (they still get rained on, dirt still settles in larger puddles and they also need flowing water to sheet properly), but with beading, the water is more likely to sit and evaporate. So always rinse a car using an open hose, ie running, flowing water, not on a spray setting. This minimises beads on a rinse. And make sure you dry the car. Remember that any wax protection will ensure that the watermarks sit on the wax, not directly on the paint, making them easy to remove. I have even found that Lime Prime Lite removes watermarks off the wax, without removing the wax itself, but you do need a durable wax for this (Supernatural or Purple Haze Pro/Blue Velvet Pro would be my recommendations in our range).
So, overall, beading is quite an interesting aspect to water behaviour and can be indicative of what's going on at the surface of the paint. But with misinterpretation and ignorance it will plainly give misleading results. Assuming a machine polished car covered in glaze oils is highly protected would be wrong. Assuming a recently waxed but very dirty car is unprotected would also be false.
And if ever there was a reason to clay and ensure good prep on paint, it's shown here... a rough, contaminated or otherwise dirty paint surface will always bead less well than a smooth paint surface - whatever is on top of it as a coating.
Finally, remember that hydrophilic drying aids like Time to Dry just affect surface characteristics. If the beading disappears, once the Time to Dry residue has worn off in a week or so, the beading will reappear from beneath (should wax be present and the surface not dirty etc).
BEADING
There's a lot of love for beading, and with good reason - it looks great and reminds you that your car is protected with wax. However, there are quite a lot of myths and misconceptions to do with beading, so we'll discuss them below. In the meantime, let's kick the thread off with some great beading:
Those tight, upright beads above are caused because the coating the water is sitting on is hydrophobic, ie water hating. Because it repels water, the water droplets try to form themselves into a round sphere - their natural state and shape. The opposite of water hating is water loving, or hydrophilic. These surfaces lower the surface tension of the water bead and cause it to spread out, creating 'sheeting'.
Remember that beading and sheeting is always a surface characteristic of material in terms of water-handling. The water droplet will only react to what it comes into contact with. It does not mean the surface is hydrophobic or hydrophilic all the way through.
MYTH 1) YOU CAN'T HAVE SHEETING AND BEADING TOGETHER
Well, yes, you can. It depends on how water hits the panel as well as the surface characteristics of the coating. If you mist water onto a hydrophobic panel, beads will result. But if you pour water from an open hose, ie you have running water, there will be no droplets formed and the water will run off, ie sheet.
So a hydrophobic surface can bead and sheet.
A hydrophilic surface will sheet.
MYTH 2) BEADING IS A GOOD INDICATION OF WHETHER WAX IS STILL ON THE CAR
OK, here's a picture below of some beading. How much wax is on the surface? Some? A little? A lot?
The answer is actually none, as it has just been machine polished, but you can get great beading on surfaces with NO protection. Perfectly smooth surfaces tend to have high surface tension, so beading occurs naturally (look at glass compared to sandpaper, both are silica materials but one is rough and one is smooth... and beading is better with one rather than the other!). Rough or dirty surfaces will be uneven and disruptive, breaking the lower part of the water bead and allowing it to spread out, due to decreased surface tension.
So good beading could be from:
- A durable hydrophobic coating being present
- A less durable hydrophobic coating being present, like a glaze oil
- A highly polished, smooth surface
And bad beading could be from:
- Dirt or embedded contaminants on the upper surface of a coating
- Microscopic damage ie roughness caused by UV damage, in the coating itself
- A hydrophobic coating having failed
- A hydrophilic coating having been applied to the coating, or at least upper surface of the coating
This is why beading is a poor guide to wax durability. You need to make sure the car is clean before judging the beading, so give it a wash (use a residue free shampoo like Born to be Mild, many shampoos are swimming in silicone which will give a 'false positive'). You need to ensure that hydrophilic - or hydrophobic - products hidden in shampoos and quick detailers have not snuck onto the surface without you realising... how many people wipe down a top wax with a cheap quick detailer without realising what is in the residue? And you also need to realise that because beading is a SURFACE characteristic, that the wax may still be present beneath the uppermost 'non-beading' layer. That's right... the beading will drop off with carnauba waxes after a couple of weeks as the UV degrades it and contaminants embed themselves into the sacrificial layer you have presented... but the wax may still be there, underneath it all, protecting the paint still.
MYTH 3) BEADING ALWAYS LEADS TO WATER MARKS
Beading that is left to evaporate on a car will lead to water marks IF there is contamination (limescale or dirt) in the water. Use a DI resin filter for the final rinse and there will be no issue. But rain water tends to be quite dirty and tap water may contain limescale. You can get watermarks with sheeting hydrophilic products as well (they still get rained on, dirt still settles in larger puddles and they also need flowing water to sheet properly), but with beading, the water is more likely to sit and evaporate. So always rinse a car using an open hose, ie running, flowing water, not on a spray setting. This minimises beads on a rinse. And make sure you dry the car. Remember that any wax protection will ensure that the watermarks sit on the wax, not directly on the paint, making them easy to remove. I have even found that Lime Prime Lite removes watermarks off the wax, without removing the wax itself, but you do need a durable wax for this (Supernatural or Purple Haze Pro/Blue Velvet Pro would be my recommendations in our range).
So, overall, beading is quite an interesting aspect to water behaviour and can be indicative of what's going on at the surface of the paint. But with misinterpretation and ignorance it will plainly give misleading results. Assuming a machine polished car covered in glaze oils is highly protected would be wrong. Assuming a recently waxed but very dirty car is unprotected would also be false.
And if ever there was a reason to clay and ensure good prep on paint, it's shown here... a rough, contaminated or otherwise dirty paint surface will always bead less well than a smooth paint surface - whatever is on top of it as a coating.
Finally, remember that hydrophilic drying aids like Time to Dry just affect surface characteristics. If the beading disappears, once the Time to Dry residue has worn off in a week or so, the beading will reappear from beneath (should wax be present and the surface not dirty etc).
