Archived posting to the Leica Users Group, 2002/03/04
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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