[time-nuts] LCD display connector

[gary]

OK. as they say, your mileage may vary. I just buy the real thing. It's 
cheap enough and works great. The price is still $7 for 32 oz at Frys. 
I'm not going to clean expensive optics with the drug store stuff.  But 
feel free to use the drugstore stuff on your own gear if you want.

I have this feeling if I ask the Walgreens pharmacist for the official 
ingredients list of their off the shelf rubbing alcohol I won't get very 
far. But it is an interesting experiment. Or do you mean MDS?

I do have some of the junk isopropyl handy. I use for cleaning auto 
parts and the camp stove. It says isopropyl alcohol anhydrous usp not 
less than 99%. No indication what the other 1% is.

Regarding denatured, you will find the 70% isopropyl is listed at the 
drug store as denatured. I have none of that in the house so I can't 
produce the label contents. I simply don't buy that stuff.



On 1/3/2011 10:16 PM, Chuck Harris wrote:
> gary wrote:
>> They mix in stuff like wintergreen oil. The FDA doesn't have an issue
>> with so-called inert ingredients. Inert for use on the body, not inert
>> in electronics or optics. Most prescription drugs are full of inert
>> materials. They don't have to be listed.
>
> Actually, they do have to be on the list as inert ingredients. The label
> that goes on the customer's bottle is never a complete label. The
> pharmacist
> has that and will give you a copy if you ask....sometimes even if you
> don't.
> That list will indicate if inert ingredients exist.
>
> Wintergreen oil, or mineral oil, or any other skin conditioner added to
> rubbing
> alcohol would be considered to be an active ingredient (it is preventing
> skin
> irritation), and would have to be listed to avoid potential allergic
> reactions.
>
>> Generally you need reagent grade to get something pure. When you do
>> chemistry, you need to know exactly what you are using. Surprises are
>> not cool in chemistry. There are even grades of reagent grade.
>
> A very well known little factoid, but we aren't doing chemistry here, we
> are
> cleaning electronics. Specifically a silly little rubber connector.
>
>> There is plenty of stuff on the denaturing chemicals on the net, though
>> it has long been known in the industry that drug store alcohol off the
>> shelf isn't suitable for electronics or optics.
>
> Denaturing chemicals only apply to ethanol, also known as grain alcohol.
> We are talking about propanol, or isopropanol, which is synthesized from
> coal, and generally sold as propyl, or isopropyl alcohol. It doesn't
> need denaturing chemicals because you wouldn't be able to stand to drink
> it... and if you did, it certainly wouldn't be pleasant, and might even
> kill you.
>
> Having spent many years working in a laser, and optics laboratory, I
> have done all of the standard tests on many different batches of drug
> store, and grocery store 91%, and 99% isopropyl alcohol, and I have found
> that it leaves no visible residue. I use it for cleaning optics, and for
> cleaning electronics assemblies routinely without problem.
>
> -Chuck Harris
>
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