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Old Aug 9, 2007, 11:32 PM   #11
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I hate to disturb you all but best check the specific item you're trying to clean. Several items I've worked with (optical and electronic) specifically prohibit ethyl alcohol but permit 90% isopropylalcohol (and prohibit 70% because that may contain perfumes).Commercial lens cleaning solutions I've encountered contain isopropyl alcohol, distilled water and a wetting agent.

I also disagree with Brian on dilution. Depends what you're cleaning. If you're essentially trying to flush away contaminates such as within a switch then dry time is important. That not the case when cleaning optics as the solvent will be absorbed by a lint free cloth (microfiber these days) and dilution is generally recommended.

Not necessarily relevant here it's 90% isopropyl that used to deice aircraft prior to takeoff. Also not relevant here is that both ethyl and isopropyl have maximum anti-microbial effect at about a 70% solution.


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Old Aug 9, 2007, 11:42 PM   #12
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TCav, most of what you have stated about alcohol is WRONG.

I am an analytical chemist with a masters degree, so I know. 100% ethanol is very rare and mainly unavailable to the general public. The reason being that it is the only form of alcohol that can be consumed. And the government wants it's alcohol taxes.

For this reason, ethanol is purposly denatured (contaminated) to make it unfit to drink. All other forms of alcohol (methanol, butanol, propanol etc) are not safe for human consumption.

For cleaning, instead of 'pure' ethanol use a high purity methanol for cleaning. Hard to come by at sufficient purity, but available and considerably cheaper than 100% ethanol. Any methanol of sufficiently high purity will be sold in glass bottles, not plastic. Lower grades of methanol will be in plastic bottles, as will isopropanol.

Alcohol will NOT disolve cotton, or certain plastics, but will disolve some plastics, so be careful what you use it on. It should have no effect on lens coatings, but again, use sparingly.

Cutting the methanol with water is really not necessary, especially as the water will have more contaminants in it than the methanol, including water from a reverse osmosis system. To get really pure water you need to buy tripple distilled water.

An additional note - all alcohols are flammable, so be very careful when using. Use away from any open flames and in a well ventilated area.
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Old Aug 10, 2007, 1:27 AM   #13
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TCav wrote:
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Even Hospital Corpsmen couldn't get ahold of the stuff.
When I was in the Navy, the Corpsman on board (a Senior Chief on a ship I was on if memory serves) *always* had alcohol (for medicinal purposes of course. He was a very popular guy on long cruises. I'm no expert on what type it was. But, I can tell you that it was ingestible (or so I've heard anyway). ;-)

Personally, I use a touch of alcohol on t-shirts and q-tips to clean my contacts (lens, lens mount, battery compartment, battery contacts). But, I use the over the counter Isopropyl kind you can buy a the corner drug store (not the kind you'd ingest).

My biggest concern with it is that water content is too high with the drug store brand rubbing alcohol (it's only about 70% pure), and can lead to oxidation and undesired residue (what I'm trying to get rid of to begin with). lol

So, after cleaning each set of contacts, I make sure the contacts are dry and rubbed well with a dry section of a t-shirt for contacts I can get to easily, and dry q-tips for the bottom of the battery compartment, after I use a touch of alcohol to clean them. IOW, the t-shirt and q-tips are doing most of the work. I just use the alcohol to help dissolve any oxidation build up.

I'd prefer to use the 90% kind for less chance of oxidation and residue from water content. But, you don't see that very often at the local drug store. So, I try to get by with the 70% stuff. I also haven't noticed any dissolving q-tips, and the plastic container (or non-glass material anyway) the alcohol comes in seems to be surviving just fine. I am careful, as I don't doubt that some materials may not like it. So, I only use a dab and I don't slosh it all over my camera or lenses.



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Old Aug 10, 2007, 7:48 AM   #14
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VTphotog wrote:
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I disagree with Tcav on diluting with even pure water. It takes too long to evaporate, and picks up dust. While there are plastics which are attacked by alcohols, coatings on glass lenses and sensors are quite robust.
Remember that I apply the water/alcohol mixture with a cotton swab, so only a very thin film remains after the swab, which evaproated quite quickly. Also, pure alcohol will start to disolve the swab, and that will leave a residue on whatever you're trying to clean. That's another reason for diluting the alcohol.
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Old Aug 10, 2007, 8:10 AM   #15
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amazingthailand wrote:
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TCav, most of what you have stated about alcohol is WRONG.

I am an analytical chemist with a masters degree, so I know. 100% ethanol is very rare and mainly unavailable to the general public. The reason being that it is the only form of alcohol that can be consumed. And the government wants it's alcohol taxes.
That's why, here in the US, 200 proof ethyl alcohol is available in liquor stores.

amazingthailand wrote:
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Alcohol will NOT disolve cotton, or certain plastics, but will disolve some plastics, so be careful what you use it on. It should have no effect on lens coatings, but again, use sparingly.
For a short period, I was assigned to the Typewriter Repair Shop on the USS Bryce Canyon, which was next to the Optial Shop. (We could use their machine shop and they could use our cleaning machine.)A friend of mine, an Opticalman, left a cotton swab in pure ethyl alcohol overnight. The following morning, when the swab was removed, the cotton appeared to be OK, but the wooden swab handle (this was before plastic swab handles) was quite flexible. When the swab was allowed to dry, the swab handle was quite brittle, and the cotton deposited a lot of dust on whatever it touched.

In my experience, pure ethyl alcohol does disolve cotton.

amazingthailand wrote:
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Cutting the methanol with water is really not necessary, especially as the water will have more contaminants in it than the methanol, including water from a reverse osmosis system. To get really pure water you need to buy tripple distilled water.
Water purified through reverse osmosis is at least as pure as triple distilled water.
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Old Aug 10, 2007, 8:28 AM   #16
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JimC wrote:
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TCav wrote:
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Even Hospital Corpsmen couldn't get ahold of the stuff.
When I was in the Navy, the Corpsman on board (a Senior Chief on a ship I was on if memory serves) *always* had alcohol (for medicinal purposes of course. He was a very popular guy on long cruises. I'm no expert on what type it was. But, I can tell you that it was ingestible (or so I've heard anyway). ;-)
On larger ships, only the doctors had access to the alcohol, but on smaller ships that don't have doctors, I suppose the senior corpsman would. But I had always understood that it was in the form of brandy (or maybe Scotch) and it's only legitimate purpose was to be administered to people that had been recovered after having fallen overboard.

JimC wrote:
Quote:
Personally, I use a touch of alcohol on t-shirts and q-tips to clean my contacts (lens, lens mount, battery compartment, battery contacts). But, I use the over the counter Isopropyl kind you can buy a the corner drug store (not the kind you'd ingest).

My biggest concern with it is that water content is too high with the drug store brand rubbing alcohol (it's only about 70% pure), and can lead to oxidation and undesired residue (what I'm trying to get rid of to begin with). lol

So, after cleaning each set of contacts, I make sure the contacts are dry and rubbed well with a dry section of a t-shirt for contacts I can get to easily, and dry q-tips for the bottom of the battery compartment, after I use a touch of alcohol to clean them. IOW, the t-shirt and q-tips are doing most of the work. I just use the alcohol to help dissolve any oxidation build up.

I'd prefer to use the 90% kind for less chance of oxidation and residue from water content. But, you don't see that very often at the local drug store. So, I try to get by with the 70% stuff. I also haven't noticed any dissolving q-tips, and the plastic container (or non-glass material anyway) the alcohol comes in seems to be surviving just fine. I am careful, as I don't doubt that some materials may not like it. So, I only use a dab and I don't slosh it all over my camera or lenses.

As ac.smith pointed out, the 70% alcohol contains a lot of thing that will leave a residue, and so may be inappropriate for cleaning. It's intended purpose is as a topical disinfectant.

And alcohol of any kind can disolve, or at the very least, damage, electrical insulation, so it's not a good idea to use it on electrical contacts. But if you keep the quantity and/orconcentration down, you can probably get away with it once or twice.
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Old Aug 10, 2007, 9:29 AM   #17
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JimC wrote:
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My biggest concern with it is that water content is too high with the drug store brand rubbing alcohol (it's only about 70% pure), and can lead to oxidation and undesired residue (what I'm trying to get rid of to begin with). lol

I'd prefer to use the 90% kind for less chance of oxidation and residue from water content. But, you don't see that very often at the local drug store. So, I try to get by with the 70% stuff.
JimC

The two places I buy 90% isopropyl are Walgreen's and Wal Mart

A. C.


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Old Aug 10, 2007, 9:55 AM   #18
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Really? Cool. My wife got the last bottle and it's only 70%. I didn't realize Walgreens had the 90% kind. We've got one at the corner leaving my subdivision. I get prints made there from time to time (upload them from home, pick them up within an hour). The one closest to me does a pretty good job.

Heck, I need to pay more attention. I was just in Walgreens about 30 minutes ago and I didn't bother to look to see what kind of Alcohol they carry. But, I don't have any contacts that need cleaning right this minute anyway.


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Old Aug 10, 2007, 10:07 AM   #19
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TCav wrote:
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On larger ships, only the doctors had access to the alcohol, but on smaller ships that don't have doctors, I suppose the senior corpsman would. But I had always understood that it was in the form of brandy (or maybe Scotch) and it's only legitimate purpose was to be administered to people that had been recovered after having fallen overboard.
Nope (not brandy or scotch). This was an unflavored alcohol (probably just a straight 190 proof kind of thing used to mix medicines or something), and the Corpsman (a Senior Chief we referred to as "Doc" since he was the closest thing to a real doctor onboard) had access to it.

I don't know what kind of discretion he had for administering it. But, let's just say that the only use of it I'm aware of didn't have anything to do with anyone falling overboard. lol

This was 30 years ago. So I don't know what they do now.

Quote:
And alcohol of any kind can disolve, or at the very least, damage, electrical insulation, so it's not a good idea to use it on electrical contacts. But if you keep the quantity and/orconcentration down, you can probably get away with it once or twice.
Suit yourself. I've been using it to clean contacts for years with no problems. The only time I can remember it being an issue was when I tried to use it (the 90% Isopropyl kind) on the contacts in an old keyboard I had spilled some coffee in, and it dissolved some glue on the portion inside where the keys contacted (it was a type that shorted etched copper where the keys touched to work), which took a little extra work to get the exposed copper on it clean and glue free again.

It must have been some kind of odd glue in places on it. Since I haven't seen that type of thing with other boards I've used it on (although I was using the Alcohol very liberally at the time, since I had a keyboard with coffee and sugar spilled all in it). I was literally pouring it through everything, even before taking it apart. lol

BTW, that keyboard still works (probably bettter than my newest Dell Keyboard), and it's over 20 years old now. I use it on an old IBM PC clone that I fire up every once and a while. It's probably about time to do that again. I want to try to keep the bearings in the old hard drive from freezing up (I've got a full height 5MB Seagate in it). So, I run it for a while from time to time.

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Old Aug 10, 2007, 11:46 AM   #20
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Hey, what type of cloth do you guys use and where do you buy them at?
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