Boring out SF's - loss of ChemKote affect conductivity?

[mcmc]

Hi,

After reading up on how aluminum oxide is very non-conductive, I was wondering about our SF lights that get bored out to accept rechargeables (like my L5 bored for 18650). That boring will rip out the ChemKote on the interior, part of whose duty it was to help keep the conductivity high, correct?

Will the oxidation that forms on the inside of the tube after boring, affect the conductivity, and therefore performance, of the light?

 

[Justin Case]

Why should it? The electrical path is through the flashlight body (which is ground). It's like a giant wire. What's on the inner (and outer, for that matter) surface seems like it is irrelevant.

Maybe it would matter if you removed the ChemKote at the neck where the incandescent lamp or LED drop-in sits and where they must make ground contact to the flashlight body. But the 18650 boring doesn't touch that area of the body.

 

[Illum]

the chemkote layer helps protect the metal surface from corrosion due to battery leak, conductivity isn't dependent on the chemkote what so ever.

how do you think 18650 bored 6Ps still work :grin2:

 

[kongfuchicken]

I think the chemkote is mainly there to prevent chemical wear if you happen to use the light near abrasive substances.
As Justin mentioned, the loss of electrical conductivity should be insignificant.

 

[LukeA]

And you can reapply a chromate conversion coating to the inside afterwards. But it's not really necessary.

 

[mcmc]

Thanks for all the replies, guys. I had a sneaking, non-electronics-background suspicion that something like that was the case. And, I feel relieved =) Makes sense that the ChemKote remaining on the tips of the tube is what matters, since that's what contacts the tailcap/head and completes the circuit. Cool beans. CPF rocks!

 

[yellow]

the only thing that suffers is the strenght of the light
(at the O-ring at the back end)

better not calculate how thick the remaining sidewall is now ;-)

 

[Justin Case]

In this thread, I estimated that the wall thickness at the tailcap next to the o-ring is 1/16" for a FiveMega 1x18650 6P clone body. At the o-ring groove itself? Let's see. ID = 0.745". OD = 0.778". Wall thickness = 0.033"/2 = 0.0165" ~ 1/60" ~ 0.4mm. Basically, when you look at the tail end of the FiveMega body, you see a thin ring of unanodized metal, which is where the tailcap makes ground connection to the body. That is about the same as the wall thickness under the o-ring.