Official Luthiers Forum!

I was wondering if the UV light I use for curing finish could also work for sterilizing stuff coming into my house. Here's the wikipedia link which describes its effectiveness:
https://en.wikipedia.org/wiki/Ultraviol ... rradiation

Here's a cut and paste of the paragraph that tells how much light is needed to kill bacteria and viruses:

Inactivation of microorganisms
The degree of inactivation by ultraviolet radiation is directly related to the UV dose applied to the water. The dosage, a product of UV light intensity and exposure time, is usually measured in microjoules per square centimeter, or equivalently as microwatt seconds per square centimeter (μW·s/cm2). Dosages for a 90% kill of most bacteria and viruses range from 2,000 to 8,000 μW·s/cm2. Larger parasites such as cryptosporidium require a lower dose for inactivation.

From this I would think it should be just a little bit of math for to get the required exposure time for my particular light.

Pat

_________________
There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

I'm thinking along similar lines. My UV cabinet is mainly used to cure Tru-Oil. It uses four 2 ft UV-A tubes (350nm). Most information that I've been able to find on disinfection talks about UV-C but I haven't found anything that says that UV-A isn't effective for disinfection. UV-C seems to have the advantage that it is less harmful to humans than A and B and I infer that this is the reason that UV disinfection devices use C. Does anyone have information on this subject?

they use uv light in certain hospital rooms used for infectious diseases. Not while patients are in the room but between patients. You should be able to dig into that to find out the dose required. Or you could find out the equivalent sunlight required to deactivate this type of corona virus and make your calculations from there.

_________________
Michael F Smith
Goat Rock Ukulele
http://goatrockukulele.com

Yah I heard about the UV light robots in some texas hospital but I don't think yhey know if it kills covid 19. Stay inside Pat

_________________
Mike McNerney

I have the same concerns about bringing stuff into the house, everything from deliveries to items from the grocery store. I haven't come up with a solution yet.

The UV light may work but it presents dangers of its own. But then I don't have one. I would like to hear what you decide.

_________________
Joe Beaver
Maker of Sawdust

Use gloves, wipe down with a bleach solution or soapy water, leave to dry, wash your hands

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I was thinking of things that might be not so amenable to liquid solution cleaning, for example perhaps getting an extra use out of a face mask. My light puts out 578 mw/cm^2 at three inches which, when I compare it to the 2 - 8 mw/cm^2 I quoted above makes me think that my light would blast those viruses pretty good. But, as I really don't know what I am talking about, I will of course take all other precautions available to me.

_________________
There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

I checked into using microwave to sterilize face masks. Most of what I found was talking about getting it wet first then streaming. People said it was a bad idea because the treatment damaged the filtering properties of the N95 mask. But, I still tried the micro by covering the metal on the mask and putting it in dry for 1 minute. I don't know if it helped or hurt but it seemed fine afterward.

I also looked into using UV. It seems it works on some surfaces if done using the right technique, but what I read was vague.

_________________
Joe Beaver
Maker of Sawdust

UV is an effective disinfectant but only for impermeable, hard surfaces and for airborne pathogens. For a breathing mask, it would kill germs on the surface but would not penetrate the filter material to any significant depth. So virus could be deeper in the filter and would not be treated.

I have no evidence that it would work, but I think a more effective treatment would be to place the mask in a washing machine and add a bit of bleach to the water. As long as the mask doesn't come apart, this should neutralize most of the virus. Another possible approach would be to soak the mask in denatured alcohol and then let it dry thoroughly.

https://smartairfilters.com/en/blog/bes ... ask-virus/
Do nothing, leave to dry for 48-72 hrs.
Lots of other info on the site, links on page

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Colin, that website is there to sell stuff. I don't get a real good feeling that their data is legit. Interesting comparison of materials to build respirators, but this is far from a reliable scientific study. Where do they get their data from? In this day, I am very skeptical in information from the internet.

I'm just about as sceptical as it comes re info from the net, it's just I was looking at that site when I remembered the query.
Fits in with all the official sources for information I've seen.

Source - The BBC website https://www.bbc.com/future/article/20200317-covid-19-how-long-does-the-coronavirus-last-on-surfaces
There are numerous others (including American studies), and all the news channels here have been answering questions about coronavirus, the one about surfaces is common.

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I saw the title of this thread this morning and wondered why I didn't think of UV light for sterilization when I was in my 20's and dating.

_________________
Ann Arbor Guitars

My 2 cents...... If sterilization of this type worked to any degree it would already be in widespread use in hospitals.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

It is. Uses UVC. Wavelengths between about 200 nm and 300 nm.
https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

It looks like the Children's Hospital of Eastern Ontario (CHEO) will be using UV light to sterilize their face masks for re-use: https://ottawacitizen.com/news/local-ne ... the-start/

_________________
There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.