Bubinga?
This wasn't "fogging". This was a distinct white streak that looked like it was on the surface of the finish. I wound up putting the stupid thing under the clip, because at that point I'd spent six hours on the dang thing and was tired of fooling with it....
There are two other causes that are not fogging related.
1. White Spots: Accelerators sometimes cause minute' pitting. Most people don't notice this, but I certainly do and keep a magnifying glass close by for inspection. If you know what you have, you can know what to do next. :wink: In these pits, CA dust will get in, and if the pits are not sanded completely out, succeeding coats of CA will make it clear for a few minutes and then - WHAM . . . white dots. Sometimes it is not the CA dust itself but simply the pits are enclosed by the next layer of CA itself trapping tiny bubbles. At first it will not show up. But after curing, the CA's curing process will make these spots show up as white, perhaps as condensation of sorts within the tiny bubbles.
2. White Streaks: When the CA has hardened well, but not completely cured, we often begin our sanding process. This is when it usually happens for me. I don't know how to explain exactly what happens but my assumptions are as follows: A small bit of CA sanding dust is trapped between the sandpaper, MicroMesh (MM) or even paper towel, it balls up; with pressure from our hand on the SP/MM - heat is created, a few tiny dust fragments harden together and then gouges into the CA layer on the pen. I would say that in some cases it might be even a sand grit that dislocated and did that - except that I have had it happen with fine MM. The common denominator for me was that I was usually in the middle to final range of MM usage when I have had it happen mostly. So this tells me that it is NOT always a sand grit.
I have had this happen on seveal occasions and they all happened when I had fairly good layers of CA. CA needs to cure well, or be sanded slowly without lots of heat build up if it hasn't cured. By running a CA finished blank at high speed within minutes after finishing and putting a paper towell or fine piece of MM on it and rubbing it with pressure, the CA dust will ball up, harden and cause scratch gouges. For me, I can duplicate this; it is predictable for me. I may not have the right terminology and may even have the wrong assumption as to the specific cause, but never the less - the outcome is same and often predictable for me.
Another aspect to the same is this, IF the gouge was caused on an underneath layer, and either dust or air was trapped under succeding coats, then you would still have the same thing. It still boils down to sanding with too much pressure or heat build up before the CA is really cured, OR a cheaper grade of SP that has a grit come loose.
I have listed several variables and not a precise answer, but I do think that this is the right ball park for looking for the answers.