All the posts about disasters lately have got me thinking about disaster preparedness.
My EDC is a McGizmo LS20. The piston is very cool. However, I wonder how it would fare in a dirty environment. Only one o-ring at the end of the piston, and if in a watery or dirty-water/sludge environment, would the piston moving back and forth allow water/dirt to get into the body itself?
As opposed to say SureFire-style sealed-off boots.
I do not know how it would hold up in a dirty environment. I seem to recall Don saying something about them being ok in most environments or something like that???:thinking:
I would venture a SWAG (Scientific Wild *** Guess) that the piston would be ok for a short time in dirty/sandy environments as long as the material has water in it as well, such as being in a body of dirty water or sandy water. In dry dirty environments such as if you dropped it in the sand on a beach or in a dirt pile, I wouldn't use it without cleaning it off first. The piston may have a problem, but so also might the bezel which, of course, you rotate for constant-on.
Personally, I would not use the LS20 or 27 in what I would consider dirty environments. I would think sealed switches are always better than the exposed piston or exposed, moving-parts switches such as twisty-bezels.
Your question is exactly the reason why I carry not only my LS20, but also my Haiku as well. That way, if I need light in a dirty environment, I have a clickie that has a sealed switch. Besides that, if you EDC only one light, you're asking for problems anyway. It's the old "two is one, and one is none" rule.
That said, I took the added precaution of putting a GITD o-ring right in-between the piston and the inner diameter of the tailcap. I don't know offhand what the diameter is, but I bought them from DX (Deal Extreme) for a couple bucks some time ago.
As you can see, it fits like a glove. Just that little bit of added protection. The o-rings Don uses are very good quality and should be ok, but I like redundancy wherever I can get it.
For the straight answer, you might want to email Don or ask this question in his area of CPF (however, that might fall under the "No Double-Posting" rule here).