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Any downside to trying to ozonating a lens for fungus?
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PostPosted: Tue Oct 31, 2017 5:14 pm    Post subject: Any downside to trying to ozonating a lens for fungus? Reply with quote

I have an ozone generator, and recently knowingly picked up a Kyoei 135 f3.5 LTM lens for cheap, knowing it had some fungus. I am thinking about gassing the lens over say a week period to see if there is a visible change in the fungi.... Any downside to doing this? I only have $28 in it.


PostPosted: Tue Oct 31, 2017 5:53 pm    Post subject: Reply with quote

Never heard of that one! Will you take the lens apart for the gassing?
Laugh 1


PostPosted: Tue Oct 31, 2017 6:05 pm    Post subject: Reply with quote

Ozone is O2, two oxygen atoms bound together. Rust is oxide of iron, from iron exposure to oxygen. There imho is the main concern.

Actually I don't think the fungus will be affected, except for some possible bleaching. Ozone causes bacteria to explode, however, there is little if any effect on fungi. In fact, the oxygen may be beneficial. Certainly there will be no removal using only ozone.

There could be adverse effects on the greases.

Some metallic-based coatings could "rust".

Not recommended imho, especially long exposures.


PostPosted: Tue Oct 31, 2017 6:08 pm    Post subject: Reply with quote

No plan on putting the generator tube in the rear of the lens and taping closed the rear of the lens, and then putting the hole thing in a box and and taping that up. Let the generator run its cycle a few times a day and check after a week. Hoping to arrest the fungi as a minimum....

this is an attempt prior to disassembly and getting at it the old fashioned way.


PostPosted: Tue Oct 31, 2017 8:30 pm    Post subject: A fair number of plugs on the net saying Ozone Kills fungi Reply with quote

https://www.cnet.com/news/killing-fungi-softly-with-ozone/

Saw this and several others googling that it kills fungi, thats what started me thinking. I will start my experiment tonight and report back.


PostPosted: Tue Oct 31, 2017 8:56 pm    Post subject: Reply with quote

Anaerobic fungi are killed by ozone. I don't think lens fungi are anaerobic. Same with bacteria, only anaerobic strains are affected negatively. Non-anaerobic bacteria and fungi may thrive on ozone...

Ozone works for odor control not due to killing bacteria but by neutralizing the smelly sulfuric compounds produced by bacteria.


PostPosted: Tue Oct 31, 2017 8:58 pm    Post subject: Reply with quote

https://sportsozone.com/index.php/download_file/view/49/161/


PostPosted: Tue Oct 31, 2017 10:28 pm    Post subject: Reply with quote

visualopsins wrote:
Ozone is O2, two oxygen atoms bound together. Rust is oxide of iron, from iron exposure to oxygen. There imho is the main concern.

Actually I don't think the fungus will be affected, except for some possible bleaching. Ozone causes bacteria to explode, however, there is little if any effect on fungi. In fact, the oxygen may be beneficial. Certainly there will be no removal using only ozone.

There could be adverse effects on the greases.

Some metallic-based coatings could "rust".

Not recommended imho, especially long exposures.


NO Ozone is O3 ! Two oxygen atoms combining to O3 while generation one free oxygen radical ! get yr chemistry right!
The free oxygen radical is hyper oxidating (and very unhealthy in respiration as such)


PostPosted: Tue Oct 31, 2017 11:15 pm    Post subject: Reply with quote

Oh my peroxide you are correct! That's not all to get right in my post, probably. Thanks!


PostPosted: Tue Oct 31, 2017 11:27 pm    Post subject: Reply with quote

As Rigel stated correctly, ozone is O3, not O2. I doubt that any "single" O* radicals will leave an ozone generator. They will most likely instantly recombine to O2, or attack another O2 and generate more O3. Nonetheless, ozone is a very aggressive oxidator. It also attacks your lung tissue and mucous membranes, which is why you should only use it outside or in a very well ventilated room where no one is staying.

Now to the lens stuff: I ozoned a hand full of fungus infected lenses. Put them in a bucket, put the generator in and just lay the lid on top. I don't know if anything happened to the fungus, but I guess no living thing is happy about such and intense ozone treatment. Concerning time, I would not recommend to leave the lens in the ozone-atmosphere for more than 4 hours. I once tried 8 hours and the rubber grip became sticky (and smelled very... rubbery). Even the paint looked a bit more dull/gray-ish afterwards! 4 hours were no problem though, so I guess the maximum will be somewhere in-between. Of course, this will also depend on how effective your ozone generator is.


PostPosted: Tue Oct 31, 2017 11:56 pm    Post subject: Reply with quote

As mentioned, ozone is an aggressive agent which has a free radical, per Wiki : "In chemistry, a radical (more precisely, a free radical) is an atom, molecule, or ion that has an unpaired valence electron.[1][2] With some exceptions, these unpaired electrons make free radicals highly chemically reactive towards other substances, or even towards themselves: their molecules will often spontaneously dimerize or polymerize if they come in contact with each other. Most radicals are reasonably stable only at very low concentrations in inert media or in a vacuum." It will be extremely damaging to any organic compounds such as coatings, or rubber grips. It WILL kill the fungus if used long enough or at high enough concentrations. However as mentioned the surface will still need to be cleaned. Might be Ok for a small fungus just starting out in an interior portion of the lens not in the optical path. I would certainly not try it for any expensive lens.

I had many many courses of chemistry in the 70's and 80's for my pharmacy training.

As an aside I did a term paper on the superoxide radical which is a related though more reactive species in biochemistry class. It is created by enzyme systems inside certain immune cells that use it to kill invading pathogens (bacteria and fungi).


PostPosted: Wed Nov 01, 2017 12:13 am    Post subject: Reply with quote

Your best bet is UV and cold cream, then CLA as normal.


PostPosted: Wed Nov 01, 2017 1:55 am    Post subject: Reply with quote

what lightshow said. Or get a 4$ tube of terbinafine cream. (an OTC antifungal cream) and use that instead of cold cream. Be sure to clean thoroughly with isopropyl alcohol or lens cleaner after using the cream.


PostPosted: Wed Nov 01, 2017 4:12 pm    Post subject: Reply with quote

jamaeolus wrote:
what lightshow said. Or get a 4$ tube of terbinafine cream. (an OTC antifungal cream) and use that instead of cold cream. Be sure to clean thoroughly with isopropyl alcohol or lens cleaner after using the cream.


Thanks for the tip on terbinafine ... I wrecked my brain here on knowing what exactly "cold cream" is supposed to be, chemically that is ... thousands of "hand creams" available.


PostPosted: Wed Nov 01, 2017 4:44 pm    Post subject: Reply with quote

jamaeolus wrote:
what lightshow said. Or get a 4$ tube of terbinafine cream. (an OTC antifungal cream) and use that instead of cold cream. Be sure to clean thoroughly with isopropyl alcohol or lens cleaner after using the cream.


Is there something in particular about anti-fungal creams that they should be washed off, rather than say buffed off jamaeolus?

I ask because I use an anti-fungal cream, and with some lenses, I've deliberately buffed it off only, in order to see if any 'active' anti-fungal properties remain.


PostPosted: Wed Nov 01, 2017 5:33 pm    Post subject: Reply with quote

IMHO Cold cream (which is a general term for any emolloient cream used for softening skin eg "Ponds cold cream") and terbinafine cream are made with a mixture of a water soluble portion an emulsifier (which lets water and oil mix, think mayonaaise) and an oil soluble portion. They should be washed off as the oil portion may penetrate the surface of the coating and damage it. Buffing will not remove the portion of it partially dissolved in the surface of the coating. though to be completely honest this statement is based only on my experience and training in chemistry and I have no experimental or reference support for it.


PostPosted: Wed Nov 01, 2017 7:23 pm    Post subject: Reply with quote

BTW did anyone ever try "DAKTARIN" cream/ointment on lens glass? It is an anti-fungal cream for humans, active compound is miconazole nitrate. It is a water based emulsion. I have been wondering.

edit: PS I looked up "Ponds cold cream" and its assumed composition. I know about the claims that are made in terms of "removing" fungus but the "removing" is very ill defined IMHO. The composition of the product is very primitive in terms of chemical materials. Wonder what is doing the trick, if any ... FWIW


PostPosted: Wed Nov 01, 2017 8:16 pm    Post subject: Reply with quote

Pond's Cleansing Cold Cream has been around since at least 1960s. Mom used it for removing rarely worn make-up. Perfect lubricant, with water, for trombone slides.


PostPosted: Wed Nov 01, 2017 8:18 pm    Post subject: Reply with quote

I've had good results with cold cream on moderately infected lenses. Obviously badly infected lenses suffer etching and are beyond saving.


PostPosted: Wed Nov 01, 2017 8:26 pm    Post subject: Reply with quote

Are we going nuclear to swat a mosquito, how much more to the much tinier fungus?

Simply changing the pH of the environment should be sufficient to kill.

Ozone exposure does not remove leftovers. The possible negative effects of oxydation, on rubber and metal parts and lens coatings and greases, don't make it more useful.

Not recommended.


PostPosted: Wed Nov 01, 2017 10:42 pm    Post subject: Reply with quote

visualopsins wrote:
Are we going nuclear to swat a mosquito, how much more to the much tinier fungus?

Simply changing the pH of the environment should be sufficient to kill.

Ozone exposure does not remove leftovers. The possible negative effects of oxydation, on rubber and metal parts and lens coatings and greases, don't make it more useful.

Not recommended.
No pH change will not kill most fungi It might slow its growth. Otherwise you could kill athletes foot with vinegar. Agree on the ozonation though.


PostPosted: Thu Nov 02, 2017 12:15 am    Post subject: Reply with quote

Okay, thanks!

Foot fungus is probably not a useful example. Indicates a deeper infection originating in the gut, which must be treated to cure the foot symptom.


PostPosted: Thu Nov 02, 2017 1:08 am    Post subject: Reply with quote

For minor fungus infestation just use UV rays. Sun isn't best choice because it warms the lens fast, making condensation which might be even bigger problem, trying to avoid lens service. Alkaline glass cleaner liquids are great for removing fungus but beware, some coating also reacts to that so always try on minor part with cotton swabs.


PostPosted: Thu Nov 02, 2017 8:58 am    Post subject: Reply with quote

jamaeolus wrote:
IMHO Cold cream (which is a general term for any emolloient cream used for softening skin eg "Ponds cold cream") and terbinafine cream are made with a mixture of a water soluble portion an emulsifier (which lets water and oil mix, think mayonaaise) and an oil soluble portion. They should be washed off as the oil portion may penetrate the surface of the coating and damage it. Buffing will not remove the portion of it partially dissolved in the surface of the coating. though to be completely honest this statement is based only on my experience and training in chemistry and I have no experimental or reference support for it.


Thanks. I'll revisit the ingredients of my cream.


PostPosted: Thu Nov 02, 2017 1:50 pm    Post subject: Reply with quote

Well a couple of days in to gassing the lens no visible change in the fungi, My generator is one for freshening musty basements, I think it generates for about a minute at a press, so I have done it a few times a day since posting with the lens in the box.

Looks like its time to take it apart and get some antifungal cream as above...