imported_doug
New member
I may have asked this question before, but I've thought about it a lot and I still haven't seen a thorough and scientific answer. One of these days I intend to experiment to learn more about this, but here is what I suspect:
Beading is not really a good indication of how much wax you have on unless you have really lousy or unclean paint. Here's why I beleive this:
Beading is a function of the surface tension of the water. (And the best way to measure the quality of beading is to look at how close to vertical the sides of the bead are.) When you have a dirty or slightly oxidized surface, the water "wicks" out and the bead sits lower. When you have a completely nonabsorbent, smooth surface, like polished glass, it sits up tall (as long, of course, as it has no detergent in it, or other chemicals from the surface or the in the water that reduce the surface tension.)
After fully preparing my car for waxing (claying and swirl removing), and BEFORE putting any wax on at all, it seems to bead just as well, which would tend to support the above theory.
So why do our surfaces bead less over time? ANYTHING that makes the surface less microscopically flat, including new swirls/micro marring (whether in the paint or the wax or the polymer) will reduce the bead quality. Also, I think that over time, an unprotected paint job will indeed oxidize a little, even if you can't see it, and it will certainly get some adhered dirt particles. These would also tend to reduce beading.
If our paint, even when clean, is truly porous, and the wax is filling in the "holes" and "leveling" the paint, this would make a flatter surface and hence better beads - and therefore also be a good indicator of how much wax was left.
But a) I am not convinced that this "porosity" exists, and b) as explained above there are other plausible explanations for the reduction in beading over time since the last wax job.
I suspect some of you know that is easy to make water "sheet" instead of "bead", merely by flooding the paint with a sheet of water (from a bucket, or hose with a low pressure stream) instead of a spray. Surface tension tends to hold the sheet together as it flows off the car. The same dirt, pores, or whatever are reducing the quality of beads will tend to break up the sheet, leaving more water on the car if the surface isn't truly clean.
SO - any paint chemists / surface finish experts out there who can enlighten us? (Or simply other thoughts or experiences that help....)
Beading is not really a good indication of how much wax you have on unless you have really lousy or unclean paint. Here's why I beleive this:
Beading is a function of the surface tension of the water. (And the best way to measure the quality of beading is to look at how close to vertical the sides of the bead are.) When you have a dirty or slightly oxidized surface, the water "wicks" out and the bead sits lower. When you have a completely nonabsorbent, smooth surface, like polished glass, it sits up tall (as long, of course, as it has no detergent in it, or other chemicals from the surface or the in the water that reduce the surface tension.)
After fully preparing my car for waxing (claying and swirl removing), and BEFORE putting any wax on at all, it seems to bead just as well, which would tend to support the above theory.
So why do our surfaces bead less over time? ANYTHING that makes the surface less microscopically flat, including new swirls/micro marring (whether in the paint or the wax or the polymer) will reduce the bead quality. Also, I think that over time, an unprotected paint job will indeed oxidize a little, even if you can't see it, and it will certainly get some adhered dirt particles. These would also tend to reduce beading.
If our paint, even when clean, is truly porous, and the wax is filling in the "holes" and "leveling" the paint, this would make a flatter surface and hence better beads - and therefore also be a good indicator of how much wax was left.
But a) I am not convinced that this "porosity" exists, and b) as explained above there are other plausible explanations for the reduction in beading over time since the last wax job.
I suspect some of you know that is easy to make water "sheet" instead of "bead", merely by flooding the paint with a sheet of water (from a bucket, or hose with a low pressure stream) instead of a spray. Surface tension tends to hold the sheet together as it flows off the car. The same dirt, pores, or whatever are reducing the quality of beads will tend to break up the sheet, leaving more water on the car if the surface isn't truly clean.
SO - any paint chemists / surface finish experts out there who can enlighten us? (Or simply other thoughts or experiences that help....)
:nixweiss 