Depending on the user to apply Kapton tape to fix a design defect might be effective, but isn’t good marketing.
If they sell 2,000 of these lights but get 200 complaints of faults that the user has to fix… ugh! The sale of the light will turn into a fiasco for Lumintop. Not everyone will have Kapton tape or want to apply it themselves to their light.
Better to just get it right the first time and design the light so getting a fault between the tubes is not possible, even if the anodizing is slightly thin or the light takes an impact.
TBH I do not trust the sort of anodising typically found on these sorts of things as an insulator.
Coming from a mil-aerospace background I do know a little about anodising, and this sort of application would need an expensive, slow, thick, true hard anodise to pass my design review.
Or some other insulating medium in-between, i.e. a collar or spacer.
For example, see TI’s design notes for mounting the good old TO-3 hermetic transistor package:
Page 3:
_The typical surface treatment for aluminum heat sinks is black
anodized(4) per MIL-A-8625, Type II. This surface treatment
prevents corrosion and maximizes thermal performance. Do
not trust this surface treatment to provide electrical insulation.
For electrical insulation, always specify hard anodized, 0.001
inch thick, per MIL-A-8625, Type III. This file hard surface
treatment resists scratches and punctures, and is typically
rated for 200VDC electrical insulation for a 0.001 inch thick
treatment._
Of course this torch is unlikely to be built to mil-spec standards (would not be affordable if so), but I’m sure there are simple ways to make the inner tube a reliable robust signalling mechanism, with a little attention to detail.
I can be wrong on this, but hasn’t a prototype not a thin oring between the tubes on the head side?
Thougt I read about it on the Taschenlampen-Forum. Would be a cheap elegant solution to keep them in place.
That could work. But I’d think you’d need 2 o-rings. One at each end of the battery tube to insure that the inner tube floats away from the outer tube at all points. You would also need slots in preferably the inner tube to keep the o-rings in place. I’m not sure the inner tube is thick enough for o-ring slots.
There are o-rings plenty thin enough. And for such a thin o-ring, not much of an indent in the tube should be needed to hold it in place. But, I still think it’s not the best solution. Then again, I’m not an engineer by trade, nor a machinist.