Baby shampoo *is* the best defog

[Dnaber]

If I could find some unscented baby shampoo I would use it again. The smell makes me sick.

 

[TMHeimer]

Has anyone tried similar stuff like other soaps--- liquid, bar, etc.-- Would any of these work?--are some maybe harmful to mask skirtings?

 

[Resqdivemedic]

I've been using a 50/50 mix of Johnsons Baby shampoo and water for years. Always worked great. Keep it in a small spay bottle in my mask case.

 

[Basking Ridge Diver]

I have been known to forget the spray bottle or baby shampoo - I never forget my spit - and it works every time.

 

[Bob DBF]

I have been known to forget the spray bottle or baby shampoo - I never forget my spit - and it works every time.

And as a side benefit, I can get a good indication of how hydrated I am while defogging my mask.


Bob
--------------
Multitasking

 

[Zog]

Few years ago diving in Cozumel, my mask started to fog up like crazy. I took it off and licked the inside of the mask, put it back on and cleared. The area where I licked stayed clear for the rest of the dive. Spit works even when applied underwater. Oh, by the way, the dive master almost died laughing watching me frantically tongue the inside of my mask at 70fsw.

 

[NAM001]

Anything that will leave a thermal barrier on the lens will work. Try a bar of soap on 1/2 of your bathroom mirror and take a soft towel and buff it in. take a shower and see the steam on the mirror surface that was not treated.

 

[Storker]

Condensation happens whenever warm moist air comes into contact with a cold surface. A thin layer of soap or shampoo won't be any kind of thermal barrier, so we will have water condensing on the inside no matter what. What soap, or baby shampoo, does is to decrease the surface tension of the water so it runs over the glass to form a thin film rather than forming an opaque layer of tiny droplets. Which component in saliva that does the same, I have no idea about.

And this is also why we burn or toothpaste the glass: To remove the hydrophobic residue on the surface, exposing the rather hydrophilic glass. Water forms droplets on hydrophobic surfaces but films on hydrophilic surfaces.

 

[CT-Rich]

Anything that will leave a thermal barrier on the lens will work. Try a bar of soap on 1/2 of your bathroom mirror and take a soft towel and buff it in. take a shower and see the steam on the mirror surface that was not treated.

If I am not mistaken, it is not a thermal barrier that prevents the fogging. Fogging is caused by condensation on the glass in your mask. Soap or saliva breaks the surface tension that creates water droplets to form on lens causing the clouding. The condensation still occurs but the droplets can't form beads, so you look through a smooth layer liquid (soap and water or saliva and water).

 

[Storker]

If I am not mistaken...

You're not. You're spot on in your understanding of the topic