[Ham-Computers] RE: Glass Cleaners and Adhesives

[Hsu, Aaron]

I'd like to add a couple of notes to what Barry wrote.  I'm not a chemical engineer, but I do work in the I.T. industry and can share some experience.

The most important thing I'd like to stress is to *NEVER* use an ammonia based cleaner on any type of CRT or LCD panel.  Most CRT's have an AR/AG (Anti-Reflective/Anti-Glare) coating that can be destroyed by ammonia; this is also true of some expensive TV's/Monitors.  Many LCD panels use optical plastic (rather than glass) and can be damaged by both ammonia or alcohol.

With this in mind, it's best to use some type of *neutral* non-alcolol, non-ammonia based optical cleaner.  Several manufacturers make this type of cleaner, of which KleanScreen comes to mind.  Camera lens cleaners can also work.  The last thing you want to do is to destroy the coating of the screen you just paid $$$ for or to slowly destroy (dis-color and dry out) the optical plastic on an LCD panel.

I've seen damaged AR/AG coatings on both monitors and camera lenses...not a pretty sight (streaked coating, un-even areas).  Be careful and use the proper cleaner.  Note that following the manufacturer's instructions may not be the best thing...for example, one HP manual states that ordinary window cleaner should be used to clean the screen, but it later warns that alcohol or ammonia based cleaners should not be used...don't most "ordinary" window cleaners have ammonia (ala Windex)?

Also, alcohol is dangerous around CRT's.  I heard about an alcohol fire starting when someone sprayed alcohol on a powered CRT.  The static build-up on the CRT caused a spark when the person went to wipe the screen and the alcohol lit up.  Not something I usually thought about until I heard the report.

Just some words of advice.

73,

  - Aaron Hsu, NN6O
    (athsu)@unistudios.com
    (nn6o)@arrl.net
    No-QRO Int'l #1,000,006


-----Original Message-----
From: Barry L. Ornitz [mailto:ornitz@tricon.net]
Sent: Sunday, April 28, 2002 5:25 PM
To: antennas@mailman.qth.net
Subject: [Antennas] RE: Glass Cleaners and Adhesives


Chris Bonde, VE7HCB, wrote:

>Eventho acetone is available in finger nail polish and 
>airplane glue, be very careful with it.  The kids sniffed 
>these common products, and after awhile had bad health.  
>Pure acetone may be even more dangerous.  Some people may 
>even smell of acetone, a usual indication of bad health, 
>as acetone like products indicate that the body is not 
>completely utilizing certain chemicals.

As a PhD chemical/electrical engineer, I have worked 
extensively with acetone [one of my former employers used 
to lose about 80,000 pounds per day of acetone to the 
atmosphere due to evaporation in one of their processes].  
I am quite familiar with its hazards. 

Bob, K2MY, is absolutely correct about it not leaving a 
residue on glass if it is pure.  As he notes, it is a 
excellent solvent for organic (but not silicone) greases 
and oils.

Fingernail polish remover is acetone with water and 
fragrance added.  The water lessens its ability to dissolve 
grease, however.  To the best of my knowledge, acetone has 
not been used in model airplane glues for many years.  Most 
modern polystyrene cements these days use methyl-ethyl 
ketone or methyl-isobutyl ketone (which are far more toxic 
than acetone).  Acetone was used back in the days of fabric 
covered aircraft wings as the solvent for airplane "dope".
I am not sure of the origin of the word, but all solutions 
of cellulose esters (like cellulose nitrate [celluloid] or 
cellulose acetate) are called dopes.

Acetone will certainly give one a "buzz" if inhaled in 
excess.  However, it is far less toxic than most other 
solvents.  I would not want to do it, but you could drink 
about a ounce of acetone without being killed.  You might ]
wish you were dead from the hangover, however.  As a 
rough measure of its toxicity, it is generally considered 
slightly less toxic than isopropanol (the pure form of 
rubbing alcohol).  "Huffing," as the stupid kids call 
inhaling solvents, is plain dangerous with any solvent.
Liver and kidney damage generally results along with 
neurological problems.

For cleaning and degreasing old gear, I often suggest 
acetone because of its relatively low toxicity.  It is a 
polar solvent, as is isopropanol, so it is usually better 
used after a first wash with a solvent such as VM&P naphtha 
which is non-polar.  This is "Varnish Makers and Painters" 
naphtha and it is a slightly more refined version of 
materials used for paint thinners.  Acetone and naphtha can 
both be bought in most major paint stores.

Acetone and naphtha, both having low flash points, are 
extremely flammable.  Thus it is best to work outdoors with 
them, well away from sparks and flames.  Wearing rubber 
gloves is strongly suggested.  The Buna-N nitrile gloves 
are best.

Acetone on the breath is something I am personally familiar 
with.  It occurs in diabetics when their blood glucose 
levels are excessive and is due to improper metabolism of 
the glucose.

Unfortunately I have been extremely busy lately and not had 
time to do more than just scan this list.  When I have 
time, I plan to write about plasticizers in vinyl that came 
up earlier when someone wrote about contaminating and non-
contaminating coaxial cable.  I also plan to write about 
stainless solders, aluminum solders, and electrolytic 
corrosion.

The issue of plasticizers, however, is appropriate here.  
If you park you car with the windows closed in the hot sun, 
you will soon find your windows fogged with an oily film.
This is the plasticizer which has evaporated from the 
auto's interior vinyl.  The vinyl left behind eventually 
shrinks and gets brittle.  The film is difficult to clean 
with ordinary window cleaners which are mainly denatured 
alcohol and detergents.  I have found that wiping the 
windows with naphtha first, followed by acetone next will 
remove this film quite well.  Finish with conventional 
window cleaner.  This can be "vinegar" based or alcohol 
based.  And by the way, pure acetic acid (industrial 
vinegar) will evaporate cleanly too.  It does a better job 
of removing inorganic spots on glass left by calcium-
containing hard water.  Any residual plasticizer left on 
the glass will impair the use of adhesives.

When cleaning plastics with virtually any cleaner, it is 
best to test the cleaner in an inconspicuous spot first.  
Acetone, alcohols, glycol ethers (bathroom cleaners), etc. 
can soften and attack many plastics.  So test first.

    Dr. Barry L. Ornitz  WA4VZQ     ornitz@tricon.net