lens coating stripping with weak nitric acid failure - reasons?

[Pherdinand]

Exactly what a professional chemist (40 years of experience with acids and a restorer of old weaponry cleaned with depotentiated acids) told me.

The only think I remember having done previously was cleanng the front surface thoroughly with isopropyl.

Ah, coming home I found the lens almost totally dissolved.

I could put my hands within the solutions with only a faint hint of sting..

😱
i HOPE you did NOT put your finger into HF (if indeed it turns out it was HF and not HNO3, as that professional chemist told you).
In fact i hope it is NOT HF.
HF doesn't burn your finger but it dissolves your bone in a short while...
it is very very bad, do not even consider playing with HF at home

 

[x-ray]

hm, my friend told me differently. In any case i'm not interested in playing with chemicals, if not strictly necessary.

I know that my friends who make damascus knives regularly use this acid to etch blades and it seems they use no special care.

i had bought it for the same purpose.

But we are in Lombardy where people build stuff in factories with a lack of precautions that might scandalize other populations.

Must be the legacy of our gallic ancestors ..... 😀

Again not to be rude but that's insane. One drop in your eye is all it takes. Just because one person is careless doesn't mean it's good practice.

I use potassium cyanide as a fixer for collodion photography. IF you're not familiar with it its used to execute criminals. It's not only deadly as a powder or liquid it releases large quantities of cyanide gas if mixed with acids or alkali. A tiny bit in a cut any you can die. I watched a well known collodion artist using his bare hands in the sution. He had a minor cut on his finger and got a thy bit of cya de in it. I saw him become seriously ill within seconds. He's luck it didn't kill him. He knew the consequences of cyanide but ignored them and it almost cost him his life.

 

[hlockwood]

I have a degree in chemistry and nitric acid should not damage glass. It sounds like you had hydrofluoric acid which will frost glass and even the vapor will.

Agreed. In addition, HF acid is very dangerous to handle. Do not let any come in contact with your skin. You won't feel the burn at first contact, then your troubles will have just begun.

HFL

 

[biginovero]

hey boys that was half humor ... in any case it was nitric acid, not the hydrofluoric hydra ... I was advised to use nitric acid in a well ventilated area (a windowsill) and with the room air flow being favorable to my safe breathing.