Archived posting to the Leica Users Group, 2002/03/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]It is true that toothpaste contains polishing agents, but its grain size is about same as the finest grain size that's use in the optical industry. There is no other way to remove a lens coating than to polish it off. Vapour deposited mineral salts (like magnesium fluoride or aluminum oxide) are insoluble in all common solvents. Maybe it would come off if soaked in concentrated potassium hydroxide solution, but that would etch the glass surface and make the lens unusable. Old coatings are usually much softer than the glass underneath. If you polish it by hand, it would take *very* long until a significant amount of glass get grinded off. Just don't use a power tool with 10,000 rpm! I treated an old Zeiss Sonnar, which had quite severe cleaning marks in the coating, with toothpaste and had very good success. I couldn't see any negative impact on the performance. Alex > In a message dated 3/3/02 4:40:46 AM Eastern Standard Time, > Dr.Alexander.Kraus@gmx.de writes: > > > I had good success removing older coatings with toothpaste in the > > past. You have to rub a little bit until it comes off, but it doesn't > seem > > to harm the glass. > > I wonder. Most toothpastes contain pumice. That's a grinder/polisher. I > guess > I'm pretty certain it will remove coatings; I wonder if it won't also > remove > glass, i.e. act like a fine polishing agent. > > Seth LaK 9 > -- > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html > - -- GMX - Die Kommunikationsplattform im Internet. http://www.gmx.net - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html