Archived posting to the Leica Users Group, 2002/03/04
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]BTW: I've seen several types of coating damage. The typical kind is damage through abrasion, that's to say light cleaning marks. Then there's fungus damage. But I've also seen coating that seems to be chemically damaged other than by fungus. One of my favourite lenses (Steinheil 35 Auto Quinaron - Exakta) has spots on the front glass that could only have ocurred through chemical action. So I'm still convinced that a coating remover must exist! Javier "John M. Sikes, Jr." wrote: > > Why do you want to remove a lens coating? Because it is 'old" or because it > is "defective", and does one relate to the other? > > ---------- > >From: Dr.Alexander.Kraus@gmx.de > >To: leica-users@mejac.palo-alto.ca.us > >Subject: Re: [Leica] Removing Lens Coating > >Date: Mon, Mar 4, 2002, 2:42 PM > > > > >> > >> >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 > > > > -- > > GMX - Die Kommunikationsplattform im Internet. > > http://www.gmx.net > > > > -- > > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html > -- > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html