Archived posting to the Leica Users Group, 2002/03/04

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Subject: [Leica] Optical toothpaste
From: Javier Perez <summarex@yahoo.com>
Date: Tue, 05 Mar 2002 04:47:23 +0000
References: <5.1.0.14.0.20020304105416.00a54308@mindspring.com> <17410.1015270924@www36.gmx.net>

Does anyone know who makes optical toothpaste?

Dr.Alexander.Kraus@gmx.de wrote:
> 
> >
> > >As a practicing dentist for the past 25 years, I can tell you that
> > >toothpaste not only will remove just about any lens coating, but will
> > also remove a fair amount of the lens element itself. You'll have a cloudy
> > lens in no time!
> 
> I don't dispute the abrasive character of toothpaste. But I can also ensure
> you that I have sucessfully used toothpaste to remove an old defective
> coating without getting a cloudy lens. I used a special toothpaste for senstive
> teeth which contain less pumice (or finer paritcles). One time I messed a lens
> up, but this was when I used a power tool for polishing. If you make a slurry
> of toothpaste and some water and wipe the lens without too much pressure, it
> takes quite a while untile the coating is polished of - and here we are
> talking about a layer of approx. 300 nanometers. I frequently check the appearance
> of the surface and as soon as the coating is gone, I stop wiping the lens
> and wash the lens with water until the toothpast is completely gone. Even with
> a 10x magnifier I wasn't able to see any cleaning marks or cloudy surfaces.
> 
> > >Toothpaste contains varying amounts of pumice and is very
> > >abrasive. I've seen patients over the years who are so aggressive with a
> > >toothbrush and toothpaste that they have removed tremendous amounts of
> > >tooth enamel such that the tooth has snapped in half due to
> > >toothpaste-induced erosion. Tooth enamel is far harder than any lens I've
> > >ever seen.
> 
> What you describe is the result of years of abuse and the addtional impact
> of agressive chemicals (acids) that are formed in the mouth.
> 
> > >As an aside, toothpaste can remove scratches in your car's
> > >paint or clearcoat quite nicely if used in small amounts on a wet rag.
> 
> I know. Toothpaste is a perfect allround polishing aid :-)
> 
> Alex
> 
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In reply to: Message from leicas@mindspring.com ([Leica] Removing Lens Coating)
Message from Dr.Alexander.Kraus@gmx.de (Re: [Leica] Removing Lens Coating)