I was responding to: wsj , not fstop
I saw complaints but it was hard to decipher them for positive advice.
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I'm WJC , not WSJ, but I think you were referring to me. Sorry to get back so late; my son and his family have been visiting the last few days.
I have offered this section from my "ethereal book" more than once. But I think it is due, again.
Bill
22 “I NEED TO HAVE THE OBJECTIVES PROFESSIONALLY CLEANED.”
The Fallacy: Thorough lens cleaning is an art beyond the capacity of most observers.
The Fact: In the immortal words of Aristotle: “Bull!”
A WARNING!: I have given step-by-step instructions on cleaning optics as simple as 1, 2, 3, 4, 5, only to have it repeated back to me as 1, 3, 5, 4, 2. Thus, to save my bacon—of which there are copious amounts—I must say I don’t guarantee one word of what I am about to say. I verify only that I have used these methods successfully for decades.
A STORY: Caring too much causes stress; stress causes a lack of confidence and dexterity; a lack of dexterity can cause optics to be damaged.
A few years ago, a fellow brought in his 4.5-inch telescope mirror for a “professional” cleaning. He carefully unwrapped it and handed it to me with the warning, “Be careful.” As I held it up to inspect from different angles, “Be careful” sounded again, as it did two or three more times as I walked to my office—the customer glued to my heels.
He had a greatly exaggerated view of the intrinsic value of his “precision optic”—a ¾-inch chunk of plate glass.
I only mention this because more overly concerned personalities damage their optics by attaching unrealistic attributes and value to them, and creating over-the-top cleaning techniques, than they would by simply treating them with sensible care.
But then, just as there’s rarely a quantifier for “better or best,” each observer has his or her own view of what constitutes “sensible care.”
So, what is the “best” chemical ingredient for cleaning lenses?
This topic comes up frequently on binocular forums and usually runs on, page after page after page, as observers vie to see who can win the most converts to their way of thinking.
WHAT DID I USE?
The short answer to this question should be: Who cares!?
Researching the Internet, you can come up with a million words on how to clean lenses and prisms. To me, these websites and posts conjure up two thoughts. First, most of them will work just fine. Secondly, why make the task seem as complex as brain surgery and frighten those who could most benefit from the information?
I subscribe to Theodore Roosevelt’s mantra of:
“Do what you can, where you are, with what you have.”
When I found it necessary—usually out of a customer-driven need for speed—I might clean a lens over a sink, washing it with a mild hand soap, and drying it off with soft toilet tissue or a scrap of clean used tee shirt, saved for just such a duty. Sacrilege? Sometimes—to those long on theories, but short on practical experience.
MY PROCESS
1. Blow off loose particulates with a rubber-based, manually operated, spheroidal, atmospheric pressurizer . . . a (new) ear syringe. Or . . .
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Photo of Air Bulb
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2. Use a camel hair brush to gentle wipe away dust. By the way, camel hair brushes may consist of squirrel, horse, ox, goat, or even bear hair. However, they’re never made of . . . camel hair. Or . . .
3. Use a shot or two of canned air! (I know the thought will make some of the A-type personalities squirm, but that’s more entertaining than TV.) Hold the can upright—8 inches or so from the workpiece, and gently move it over the surface. If you shake it, move it too quickly, or don’t hold the can erect, you run the risk of spraying propellant on the element. That’s not the kiss of death as some believe. Still, unless you’re confident, leave canned air out of the equation.
Optical cleaning solutions and techniques come with all sorts of formulae and recommendations. You’ve seen them: Mix 1% this with 3% that, and then add . . . . These can take 300 words to describe and be confusing to some. Such formulas may be useful for medical applications, or in some aerospace environs, but are incredible wastes of time for even the most critical binocular observer.
I found three cleaning solutions to be the most practical.
1. The first is a light ammonium hydroxide mixture, known to the more scientific among us as NH4OH. To make this chemical at home, you start with 4 ounces of household ammonia, to which you add 16 ounces of rubbing alcohol, and add 1 tsp of dishwashing liquid. After this, add enough water to finish filling a 1-gallon container.
To those lacking in spare time, or don’t care about besting their neighbor’s secret formula, I would recommend buying it off the shelf; it’s commonly called Windex®. Windex has been around since 1933 and has part of the S. C. Johnson family of products since 1993. The chemical giving Windex its blue color is called “Aqua Tint.” It’s not necessary, but originally filled an important marketing role; it showed homemakers they were buying something more than water. If you have to have blue liquid and Aqua Tint is not readily available—and it won’t be—you may use a few drops of blue . . . food dye.
2. The second product I found indispensable was De-Solv-It® by Orange-Sol. Sold in about 60 retail chains in the U.S., it can be found in most leading grocery stores. But why, if you’re already using Windex, do you need anything else? Because different stains require different cleaners. De-Solv-it (also around since the ‘30s, although originally sold under a different name) will remove sap, gum, and tar based stains that would resist acetone. Conversely, acetone will remove things De-Solv-it won’t touch. Sometimes you need at 3-iron; sometimes you need a pitching wedge.
THE PLOT THICKENS
The final product I used was acetone—(CH3)2CO. As pointed out earlier, acetone is NOT the culprit in the removing of lens coatings, nor is it, despite the urban legends, a carcinogen! In fact, this simplest of ketones is organic and is produced in our own bodies.
Even so, there are some important cautions that should accompany its use.
1. Acetone will dry your hands quickly. Thus, you should apply skin cream or baby oil if you get as much as a teaspoon of it on your hands.
2. You should also use caution must around plastics, as it will melt some types, instantly. A former co-worker once dropped a touch of paint on my new HP printer. Thinking he would wipe it off before it had time to set, he used a rag doused in acetone. In less than three seconds, he had the tiny drop of black paint spread over the side of my new printer, with fibers from the dirty red cleaning rag imbedded in the plastic as well. Further cleaning was forever out of the question; I could only learn to appreciate the printer’s new artistic look.
3. Acetone was my most useful solvent. However, it evaporates very quickly, which can lead to other problems. Acetone is hygroscopic and will quickly draw moisture from the air. Special reagent acetone is not called for; the hardware store chemical will work fine.
To use on optical surfaces, however, it should be “dry”—moisture free. A cotton swab holding a drop of acetone, that would perform its job wonderfully, would be worse than useless should you wait even 15 seconds to use it. Why useless? Because, being hygroscopic, it would just move a sheen around, and you would grow old trying to clean the workpiece, and only succeed in making a bigger mess.
So, to use this godsend chemical, you should touch the swab to the acetone, flick off the excess, wipe the surface in swirling motions—starting at the center—and discard the swab by the 8th second—the 5th would be even better.
In referencing cotton swabs, I mean surgical swabs (~$10.00 per 1,000, 2014 price) with a wooden applicator. If you use a “Q-tip®,” with its soft plastic applicator, you will melt the plastic and make a mess on the workpiece. Urban legends notwithstanding, acetone is safe and efficient to use, as long as it’s mixed in equal portions with common sense.
Then there is ether, ethanol, propanol (isopropyl alcohol), colloidal, and on and on. I rarely address cleaning optics without someone piping up and intimating that I may not have the best solutions or techniques. That’s fair; I think most of them should get a life, go use their binoculars, and stop reinventing the wheel. No, I’m not set in my ways—yet. It’s just that I like to keep things simple and inexpensive.
Finally, those hoping never to run out of things to worry about should note that even distilled water will etch glass, and if they have a few thousand years to spare can prove this to themselves.
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Photo, Illustration, or Comment Photo of Micro-Ripple on a GREAT mirror
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THE TISSUE ISSUE
As a student at the Navy’s Opticalman “A” School, I had several cases of fresh lens tissue at my disposal.
Joining my shop aboard USS Grand Canyon, in Mayport, Florida, the first thing I noticed was the workbench and the rolls of toilet paper (White Cloud or Charmin) that sat in front of each toolbox. I had now joined the REAL world.
One thing concerning lens cleaning that I do find important relates to the type of lens tissue most often used.
Starting with its use in ophthalmic dispensing, many people believe you must have lent-free lens tissue to do a proper cleaning job. That’s not so. It may be lint-free, but it’s not very absorbent and, that lack of absorbency, may lead to a scratched optic. Something to worry about? No. Something to consider? Yes.
The lint-bearing tissue is thicker and softer. Therefore, you can often feel embedded particulars and remove the pressure before any damage is done. Of course, it will leave lint. Even so, the more adventuresome of observers, can return to the air bulb, a ¼-second shot of canned air or, heaven forbid, a puff of human breath. Technical? No. Efficient? Yes.
Do what you can, where you are, with what you have!
