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How is the "etched code" on some glass tubes (and all Philips tubes) made. I have seen the term 'acid etch' used, but I don't think acid can etch most glass. I know very strong acids can be stored in glass bottles. Just wondering-
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Kind of interesting experiment video illustrating what hyrdofluoric acid can do.
Edits: 08/11/16
For informing me about Hydroflouric acid. I took two semesters of College chemistry and thought like the professor, that glass was "our Friend" and never came across or forgot about this acid. It appears to be a very dangerous and difficult chemical to work with, especially in an industry that was turning out ?hundreds of tubes per minute" or whatever number it was. I noted that the same guy has another video about hydrofluoric acid available on Youtube with approx. 1.7 million hits, with a title The Flesh Eating Acid! I think the only acid we used in the Chemistry lab that was a strong and dangerous acid was X Molar Sulfuric Acid.
Well then Acid Etch it is!
Proper precautions allow the hazardous substance to be safely employed.
While they are targeted for elimination, incandescent light bulbs are still being made. Those that are "frosted" use an envelope that was etched, on the inside, with hydrofluoric acid.
Eli D.
favorite light bulbs. I guess it makes sense that an electron tube user/lover would also favor that kind of light bulb.
When the highly energy efficient bulb policy was first implemented, stores in my area, no longer carried the old incandescent bulbs, much to my consternation. Fortunately the did start to carry them again, and they seem to be everywhere.
Now if we can get Philips to go back to Hicksville.....
Steve,
Just a guess, but I suspect hydrofluoric acid is uesd. Can be very nasty stuff.
Correct, H 2 F 2 is used to etch glass. The SiO 2 in glass is converted into volatile SiF 4 .
While technically weak, which means the amount of solvated protons produced when dissolved in H 2 O is low, H 2 F 2 is highly corrosive and must treated with great respect. Rubber, plastic, wax, and lead are what's used to contain the nasty stuff.
Eli D.
Another way to deal with something that etches or corrodes everything is to wait until you need it and make it then.
Also calcium is what is used to neutralize it so it is literally "bad to the bone"
mt
nada aqui
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Buy Chinese. Bury freedom.
.
nada aqui
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Buy Chinese. Bury freedom.
Wax or lead. When hard rubber came along, it was also suitable.
It is possible to generate hydrofluoric acid "in situ" by using sodium fluoride and sulfuric acid. That mix etches glass "like gangbusters".
The etching occurs as silicon dioxide is converted to volatile silicon tetrafluoride and water. The silicon tetrafluoride vaporizes (a product is removed) and, per Le Châtelier's principle, the reaction is driven to "completion".
If lots of the acid is present, all of the glass will be consumed. Lots of glass and little acid yields the results we see.
Eli D.
It can rid your tub of the most stubborn stains...and rid you of your tub, too...
Think they are acid etched.
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