I'm a former chemist. What evidence is there that the pH of the APC is the culprit?[/QUOTE
Thanks for chiming in Chet. I am glad that we have a chemist in the house. I am an only an ME so I would like to hear your opinion. There was a discussion on another thread of how Meguiars D101 left a cloudy white residue on a black vinyl dashboard and the member was afraid that he ruined the interior. I looked at the pH of the chemical and the level 13 seemed too harsh to me. Even with a 50:1 dilution and a pH of 11.292 it still seemed too alkaline. If it is not the alkalinity, what else could it be?
You're only an ME? OK, I'll try to make this simple (joking, my son is an ME, I know how tough that degree is). A caveat, soap/detergent chemistry is sophisticated and I was not a soap chemist.
The point I was trying to make is that there are other chemicals in the APC that could cause the whitening. Ideally, we'd design an experiment simply using sodium hydroxide (NaOH) and distilled water, with no other chemicals. Wash a section of the dashboard with distilled water, wash a section with 0.001M NaOH (just NaOH + distilled water, nothing else, pH 11), a section with 0.01M NaOH (ph 12), and a section with 0.1M NaOH (pH 13). Properly rinse all sections. Check for whitening. That would tell us if high pH alone was the cause of the whitening. Actually, it wouldn't totally tell us that, you'd have to run the same experiment with other bases, but it would be a start.
We're also dealing with harsh detergents in the APC that can do damage. A harsh detergent can remove wax from clear coat. So could it damage plastic? I suppose (another experiment). More likely, there could have been 5 coats of old Armor All on the dash, and the APC would certainly would go to work on that.
Anyway, it could be the pH, or at least partially the pH, but it could also be the detergent or even some other additive causing the problem. Some kind of unlucky combination of what was in the APC what was on the dashboard.