Sick S8612

[OlDoinyo]

In the case of U-type glass, which are variants of Wood's glass, Wikipedia has the following tidbit:

 

Wood's glass is special barium-sodium-silicate glass incorporating about 9% nickel oxide.....The nickel and barium oxides are also chemically reactive, with tendency to slowly form a layer of hydroxides and carbonates in contact with atmospheric moisture and carbon dioxide.

 

So in that case, the efflorescence is not thought to be caused directly by oxygen per se.

 

I have been unable to find similar information about what is in BG-type glasses--only hints that some copper, tin, or antimony oxides might be involved. So it is harder to guess the chemistry there. Perhaps it is similar, or not...

 

In my experience, cerium oxide is your friend! It removes the deposits quickly and efficiently, and does no appreciable damage to the underlying glass.

[colinbm]

Thanks for the tips, especially CO2.

In the BG type glasses they have over 70% Phosphorous Oxide & it seems it is that we are needing to stop from corroding / leaching from the BG type glasses.

As has been explained by Dave Debateman that it is more aggressive then silica gel at absorbing moisture from the air.

[ulf]

"Know thy enemy" seems to be the best defense, to win this battle.

We need to neutralize this enemy.

 

 

This might be usable information to better know the enemy, even if it is not about filter glass:

http://www.vam.ac.uk...ation-of-glass/

[colinbm]

Thanks Ulf

This is rather informative.

There is hope in finding a solution in all respects.

I am encouraged by this piece....

" Hogg investigated the possible application of silanes to the surface of the glass ⁶ . By applying a single atomic layer of molecules to the surface it is possible to turn the hygroscopic glass surface hydrophobic. This work was again carried out on replica materials and found to repel water. It was also noted that the surface treatment did not alter the appearance of the glass surface to the human eye, and remained smooth. The application of surface treatments does, however, pose an ethical dilemma in that these treatments are not reversible. "

[OlDoinyo]

I don't know what method Hogg, et al. used for their surface treatment studies. But here is a sort of how-to, if one could get one's hands on the materials:

 

https://www.gelest.com/wp-content/uploads/09Apply.pdf

 

There is also a product called Rain-X, sold for car windshields, that contains polysiloxanes (not silanes) but does render a surface hydrophobic (temporarily--it seems to wear off with time.) I don't know if a truly invisible film of this would be easy to engineer.

[colinbm]

Thanks OlDoinyo, this looks promising & simple & doable, & certainly along the lines that I was hoping for with a consumer application.

I have actually applied some RainX like product, Invisible Glass, to a clear UV cut filter & have been giving it two days to dry properly & the glass look clear as would be expected.

I will get it checked out with a spectrometer to see if there is any transmittance change.....?

I'll give the other experts time to voice an opinion.