Many copper flashlights are uncoated. I have 3, and all are uncoated.
Copper isn’t anodized, but some manufacturers might coat the copper with a layer of plastic. Something like Protectaclear. But most copper flashlights seem completely uncoated. You can tell these ones because they develop a patina like an old penny.
Copper is antimicrobial via the oligodynamic effect. But if you’re thinking you’ll clean your hands of coronavirus by fondling your copper flashlight in your pocket you should think again.
Covid-19 can survive for up to 4 hours on copper. This is shorter than the 3 days or so on steel or aluminum, but clearly longer than is practical for most purposes.
Basically with an all-copper light, you can probably set it aside, come back 4 hours later and then reasonably assume that any Covid-19 on it is dead. Of course this only applies to the copper pieces though. Even lights made from copper have portions that are made from other materials where Covid-19 can survive longer (clip, lens, switchboot or button, etc.).
silver works even better, and it stick really good to copper during galvanization process. it should not be that hard to galvanize one with silver, should it?
I’m by no means a virologist, however as physician, perhaps I can clarify some concepts behind how some materials are considered superior to others in being “anti-microbial.” If you find any mistakes below, please let me know as I’m very open to learning new things.
According to this article, COVID-19 is theorized to be like other viruses in needing a certain infectious dose to cause disease, known as the ID50 number. This number is how many viruses are needed in one exposure to cause disease in 50% of exposed susceptible individuals. Therefore a single virus on any surface is highly unlikely to cause disease. Of course the more viruses, then there is an increase in likelihood of disease.
This article points to what researchers believe to be how copper kills microbes. And in the case of COVID-19, the preliminary research shows 4 hours of contact on a copper surface will reduce the number to non-detectable levels, or at least cannot be cultured. It may reduce the virus to below infectious doses before the 4 hour mark is reached. This killing process requires oxidation of copper (therefore coating to preserve the shine will greatly reduce efficacy), and increased humidity and heat can speed it up. (Good for those with sweaty hands?) And this applies to most if not all microbes, not just COVID-19.
So what does this mean for flashlights? Let’s say I use a titanium high CRI flashlight in the clinic to examine skin. Microbes on the titanium can survive longer and remain at an infectious dose for a longer period. If I use an uncoated copper flashlight, the infectious dose will remain viable for a shorter period of time, therefore reducing my chances of getting sick from contact. It’s a reduction in risk, not a guarantee.
Disease and infection are not binary, rather a process of logarithmic/exponential decreases and increases. I would prefer to carry a mildly stinky copper flashlight at work because it can reduce my chances of harboring harmful microbes on that one instrument. Of course, I would not rely upon that to increase safety. The primary measure would be wiping down all my instruments and hands with alcohol and/or washing my hands between every patient.
Sorry for the long-winded response, but I hope this might clarify the utility of copper.
haha, good thread, thanks everyone. I’m interested in copper not so much as a hand washing replacement. But, you know how it’s nice to have an 18650 light that can also handle CR123A’s? It’s kinda like that. An extra feature that makes a light just nicer to own.
While not fully related to flashlights, but related to copper, but I am not sure why it is not mentioned more often that various copper forms (one of which oxide, and many others) are used for a very long time as a contact fungicide on plants, maybe many do not have plants, maybe do have but use the more high-end substances that are patented by big companies that are system fungicides (thus more effective compared to contact), but surely this is something has been done for a very long time by so many people, including in our family.
So it’s proprieties are not as mythological as seen by some.