Is chrome a poor conductor?

Flashlight Modding and DIY Parts
1

I have a light with chromed caps over the positive and ground springs. I was testing for continuity with my DMM probes and couldn't get continuity tone. I tested without the caps and everything checked out.

I then placed both probes on the cap and got no confirmation tone. I finally scratched the tips onto the cap a little and got a tone.

What is the electrical conductivity of chrome? If it's really poor, it makes copper braiding the springs kind of pointless. Should I grind the chrome off the top of the caps? It sure looks pretty though.

2

Yes. And toxic, be careful scratching it, extremely careful grinding it.

http://www.radiall.com/media/Guide%20PLATING%20D1C004XEe.pdf

3

The electrical conductivity of chrome is usually considered ‘good’ but usually 5 to 10 times worse than copper.
I say usually because chromium can be plated as an alloy to enhance the electrical properties. Usually when we think of chrome, it’s hard chrome (like you would see on your car bumper or hand tools like wrenches and sockets -try your ohm meter on these and you should see, it’s not so great). If your working with ‘decorative chrome’ and it looks mirror like, it’s probably layered over several layers of nickel -it’s too thin to remove the chrome without removing the nickel. Chrome develops an oxide layer like most other metals, but you don’t see it because it’s clear.
I would check to see what the base metal is -use a magnet -if it’s magnetic -it’s steel and no better than the chrome layer. If it’s non-mangetic, I think it would be worth removing chrome layer…you may have brass under there.
I build my spring caps out of copper…brass is more corrosion resistant, but I feel like I’m cleaning my spring caps every time I screw it down on a battery.

Let us know what you find out.

4
Nickel is often mistaken from chrome. Nickel is commonly used to plate anything even plastic that is called "chromed"

The "chrome" on caps can also be tin or silver. No one actually chromes anything for electrical contact purposes.

5

He had trouble getting a reading with his ohm meter…that doesn’t sound like nickel. tin or silver.

6
Well.. why anyone would use chrome for such purpose? Toughness? usually for contacts that require high friction resistance tungsten is used.
Usually if you are looking for contact caps, contact tips, etc, most are made from a variety of silver alloys (with nickel, cadmium, zinc).

Taking a guess about a spring covered in a cap, that would be an Armytek flashlight? EDIT: Answer is no

7

Actually, it's a Boruit Z001.

Here's a picture I borrowed from an OldLumens thread.

8

Well, it does look like chrome. I think the next thing to do is the magnet test…(very small magnet, it looks like your driver is just under the contact) if the magnet sticks, there’s steel under the chrome. If it’s steel, you’re probably done (at least with the positive contact in the picture). Looking at the picture, I think I can see a brassy color around the inside of the large chrome part -check yours. If they used chrome on brass for the outer part, my guess is they used chrome over brass for the contact point.

Have you taken out the 2 screws?

9

Bare chrome is not very good. We design and build display type devices at work and have to make an electrical connection onto conductive glass. This is done by evaporating chrome pads directly onto glass, with a thin layer of gold on top.

10

I removed the chrome off the tops using a flat file. I'm getting an instantaneous continuity tone from my ohm meter now.

I guess I'll buff it up with my dremel now.

11

Elemental chrome, ie: the metal is not toxic at all and no special precautions need be taken when sawing or filing other than those for regular dust.
Having said that, hexavalent chromium (Cr(VI)) compounds, on the other hand, are both toxic and carcinogenic.
A bit like mercury in many ways.

Elemental mercury or quicksilver, despite the almost hysterical paranoia surrounding it these days is actually, relatively harmless.

In 2016 a Libyan 3 year old toddler drank almost the entire contents of a two-thirds full, 100ml bottle of mercury.
Not only did the child survive, he did not appear to be harmed in any way.
Here’s an excerpt from the boy’s medical case notes:

“A Libyan boy aged 3 years who ingested approximately 55 cc (750 grams) of elemental mercury was admitted to the Pediatric Emergency Service for further diagnosis and treatment. We learned that his uncle, who worked in silver processing, kept 60 cc of liquid mercury at home. The patient’s family reported that he drank from the bottle and only 5 cc of mercury remained. He was immediately taken to a nearby emergency unit after receiving gastric lavage and the administration of penicillin; the boy was transferred to our clinic for further diagnosis and treatment.”

“The patient had no symptoms when he was admitted to our clinic after 2 days following oral mercury intake. The patient had no acute or chronic gastrointestinal or other systemic diseases.”

“In the physical examination, the patient was conscious, cooperative, and orientated. The respiratory and cardiovascular system examinations showed no signs of abnormality, and the abdomen was soft and non-distended. There was no tenderness, rebound or hepatosplenomegaly. Neurological and other system examinations were normal. There were particles of mercury on the patient’s diaper.”

Read the full report here at the: Balkan Medical Journal

Now the bad news. The really bad news.

Organic mercury, (compounds of mercury that include carbon), is extremely toxic.

A scientist who was working with a solution of dimethyl mercury (H₃C-Hg-CH₃, an organic compound of mercury), spilt two drops on the dorsum of her latex gloved hand. Six months later, she was dead.

The following video is both frightening and harrowing: