Good contact against aluminum?

[Commie]

I'm working on another double-barrel flashlight mod. The first one felt very anemic and I couldn't figure out why. I think I did now.

In the process of putting it together, I checked resistance between negative battery connection spring (connected to the ground) and the steel bolts that hold flashlights together (also ground). I get about 0.8 ohm

I assume the bolts don't make a very good contact with the aluminum body, and, as I recently learned, solder doesn't stick to aluminum.

So -- is the extra .8 ohm in the circuit gonna mess me up noticeably in a non-VV mod? And if so, how can I improve on it? JB Weld the bolts to the holes? The holes are already as sanded as they can be, I think.

Thank you for any input!

 

[asdaq]

You subtracted the resistance the meter has itself, yes? Any anodized layer insulates the aluminum too. Could we see the first one to get a better image of what is going on?

 

[PoppaVic60]

They actually made home wiring of aluminum for awhile..

Yes, anodizing might as well be paint- got to get to the metal.

I *know * there used to be an aluminum-solder.. I had it.. Kestels or something. However, I can't recall if it was "not for electrical". Screws and rivets and grommets still work.

 

[martinc]

A rivet is still the best attachment as it expandends and fill the hole,making good contact

 

[Commie]

You subtracted the resistance the meter has itself, yes? Any anodized layer insulates the aluminum too. Could we see the first one to get a better image of what is going on?

The first mod? Sure, though it was a *total* mess. Was my first attempt, the concept was very cool, but I got too cocky with implementation (I mean what can possibly go wrong, just a few solder points) and epoxied it shut so I can't fix it now. Even the concept had a flaw where a recessed 510 connector made it difficult to unscrew tanks like Vivi Nova that made it possible for the tank to come apart rather than unscrew.



In the second version I'm trying to avoid the same mistakes and go for cleaner and smaller construction.

I did sand the paint off in the places of contact, and I think I will sand the area where the two flashlights touch each other. It might also be resistance of the cheap battery spring inside a $1 flashlight. I might be able to solder a washer to it for better battery contact.

This time it will be possible to take it apart so I can eventually replace the cheap switch (possibly with touch sensitive switch).

 

[SammyT]

Aluminum can build up oxidization, perhaps some noalox would help? You can buy a little from vendors at a mark up, or at lowes/home depot in a white bottle with a blue label in the aisle with the outlets. Just a dab'll do ya, you don't want to gum up the works.


-Sam

 

[Commie]

Sweet! Thank you!

 

[slimest]

Everything depends on current used. If you vape on high volt with relatively small currents, cheap aluminium lights can do. Maybe. But if you prefer 3.7V vaping, particularly with booster and high power, you should consider something more reliable than a cheap light springs ang threads. Noalox could help, but better to use a more reliable design, say brass inserts into springs etc.

 

[asdaq]

Now I remember, thanks for upping the pics. You can track down what is the source of the problem in this one by testing the resistance from point to point, like the end of the spring to the other end of the spring, end of the spring to the joint between flashlights, and so on. Then you can isolate which part / connection is the culprit.

 

[Commie]

Thank you guys for all the advice! Between sanding, noalox, and soldering a washer to the battery spring, I got the circuit's resistance down to 0.1 ohm. Yay!