Anti-Fogging Treatments for New Masks. (a comparison of techniques)

[lowviz]

Boiling point of Ammonia is -33C (-28F). Explain your boiling process...?

Heat in microwave.

I was hoping that this was enough of an explanation:

I tried my 'go-to' for baked-on crud, household ammonia.

@RayfromTX: Thanks for the DSR-5 post!

I chased it down and it seems likely that it has decalin in it as a major component. It appears that decalin was found in the 1940's to be a good cleaning agent for silicone oils/grease on glass. Very useful bit of information.

I no longer believe that the fogging problem is as much a silicone oil film issue as it is an un-hydroxylated (hydrophobic) glass surface problem. Hydrophobic glass surfaces can be converted to hydrophilic surfaces with either strong acid or a strong base. Ammonia is basic, Aspirin is acidic.

 

[RayfromTX]

This is my understanding. We use a surfactant to make the glass hydrophilic. We use the cleaning methods to make the surfactant effective for a longer period of time.

I tend to think it is a silicone migration issue that requires treatment because it recurs when the mask is left in an airtight plastic box for a long period. I also watch the fogging on my windshield and the patterns from the suction cups and the patterns that redevelop as the dash migrates polymers onto the surface of the glass after months of sitting in the sun. I also have experience with damage to insulated glass units that used silicone spacer bars which I think is caused by silicone migrating onto the coatings used on the low-e glass.

My wife uses a mask that has nano-particles on the surface to resist fogging. She still needs a tiny bit of defog but less than mine. Hers has never been cleaned in any aggressive way which may mean that the nanotechnology also resists the silicone particle migration from adhering to the surface. shrug

I think I have mentioned this but sea-drops gold is my favorite defog. Not the gel but the cleaner/defog version. I put it on very thin at home and let it dry. a few minutes before ready to dive I put water in the mask and let it sit pooled on the lens. A few minutes later I dump it out and if I haven't applied it to thickly, it is ready to go and lasts for several dives; although I usually reapply between dives. If I'm rushed or forget I don't have a problem but others on the boat have. I suspect their mask never got cleaned as well as mine but nobody has reported a fogged mask with the sea drops gold when applied between dives if their mask was cleaned at all. (toothpaste, flame, agressive soap scrub or whatever method they might have used)

 

[lowviz]

This is my understanding. We use a surfactant to make the glass hydrophilic. We use the cleaning methods to make the surfactant effective for a longer period of time.

I have found research articles that claim that a clean glass surface can be either hydrophobic or hydrophilic depending on the chemical nature of the silicon oxide surface.

The glass surface's water wettability depends on the degree of hydroxylation of the surface silicon (hydroxylation of the silicon in the glass). Strong acids or strong bases (alkali) hydroxylate the surface. So it seems to be that one wants Si-OH groups on the surface of the glass for wettability. You can react Si-OH with TMS (trimethylsilyl reagent) to get Si-O-Si(CH3)3 groups and now you truly have a mask from Hell.

I no longer think that the problem is coming from the silicone skirt. I believe that it is simply the problem one has with keeping a clean surface clean. Clean isn't the full answer, though. That clean surface can be water wettable or water beading.

A clean but water-beading surface can be overcome by coating it with defog. The defog is physically covering the water-repellent (and defog-repellent) surface and the net result is that the mask doesn't fog. A better approach is to convert the glass surface to its hydrophilic (water-loving) state and then apply defog. The defog now is attracted to the glass as both the glass and the defog are hydrophilic.

Either way, you need some sort of defog to protect the clean glass surface. My preference is spit on a clean hydrophilic glass surface. It works just fine. In addition to spit, household ammonia is a great cleaning agent as it both cleans crud really well and it converts the glass surface to its hydrophilic state. Cleaning the glass, applying a thin coat of straight baby shampoo and then storing is the next thing that I will examine before I wrap this up. I believe that I got to where I wanted to be with respect to mask fogging.

I totally agree with the nanotechnology approach. -doing everything right. But that approach is outside the scope of this investigation...

 

[saxman242]

no longer think that the problem is coming from the silicone skirt.

How does a mask that doesn't fog, that is then stored in a sealed box, come out dirty if it isn't the silicone outgassing?

 

[tridacna]

How does a mask that doesn't fog, that is then stored in a sealed box, come out dirty if it isn't the silicone outgassing?

Silicone is an inert solid. It does not "outgas". Residual mould release agent may be responsible for this if not properly cleaned from the mask. Perhaps this is why the dishwasher treatment could be good.

 

[lowviz]

I no longer think that the problem is coming from the silicone skirt.

Maybe a better way to state this is to say that "I no longer think that this problem can be solved by just cleaning the mask glass and skirt. A critically cleaned glass surface won't stay clean for very long.

Clean, coat with defog, dive.
Dive, clean, coat with a storage film.

I use a thin film of undiluted baby shampoo to protect the glass while in storage.

 

[RayfromTX]

Silicone is an inert solid. It does not "outgas". Residual mould release agent may be responsible for this if not properly cleaned from the mask. Perhaps this is why the dishwasher treatment could be good.

This is a claim that is not supported by this and other articles about cured silicone. This article is supportive of many of the things we have observed and suspected throughout this discussion.
https://imageserv5.team-logic.com/mediaLibrary/99/Outgassing_20of_20Silicone_20Elastomers.pdf

 

[lowviz]

That research article clearly supports @saxman242's position on outgassing...

 

[saxman242]

Silicone is an inert solid. It does not "outgas".

Even controlled volatility silicones used in space applications have outgassing rates in the .1-.5% TML range (when tested to ASTM E 1559). They most certainly do outgas, they just don't outgas much. The problem is that silicone contamination is incredibly difficult to clean and it takes very little to contaminate a surface. Some of the casting silicones that are peroxide contaminated (and used often in injection molding applications) outgas a whole lot.

I'd love to know if mask manufacturers are post curing their skirts at all too.

 

[RayfromTX]

Post curing of masks seems so unlikely but I have no info. Here is a blurb from Aqualung which reminds me that is I was going to use DSR-5 to clean the mask I would be careful to not let it attack the seal at the edge of the glass. I would try q-tips for the careful application.

Here is the Aqualung recommendations.
Care and Maintenance - Mask


The following Care and Maintenance information is provided for products that do not have a specific owner's manual and is intended as a general guide for basic care and maintenance of your Scuba Equipment.

Mask Care and Maintenance
Care Before the Dive:

1. During the manufacturing process, a thin film of silicone will develop on the glass lens. This film of silicone will cause rapid fogging that is resistant to conventional anti-fog measures. It is important to remove this film of silicone from the lens prior to your first dive. To remove the film you will need to scrub the lens inside and out with a mild abrasive. A paste toothpaste is ideal but a liquid scrub will also work. Rub the cleanser into the lens with your fingers several times and then rinse clean thoroughly.
2. Mask fogging is a normal occurrence, even after the film of silicone has been removed. Normal fogging can be easily prevented with after market anti-fog agents or saliva. Rub onto the lens and then rinse. Your dive will now be fog free!
3. Some after after-market anti-fog agents contain formaldehyde, alcohol, or other substances that may damage the plastic materials used in your mask. If unsure, avoid prolonged exposure of the anti-fog agent with the plastic parts of your mask.

Care During the Dive:

1. When entering the water either from a boat or a beach, place a hand over the lens of your dive mask and hold it securely in place. This will help ensure your mask stays in place during entry and will help deflect any direct impact of water on the lens caused by the jump into the water or any approaching waves.
2. A typical dive staging area is a dangerous place for dive masks. Care should be taken to not leave your mask in a location where it might be exposed to dropping weight belts or tanks.
3. It is best to avoid putting your mask on your forehead at any time during the dive. Several factors can cause the mask on your forehead to be dislodged and subsequently lost. If you want to temporarily remove the mask from your face, place the mask around your neck.

Care After the Dive:

1. Soak in warm fresh water (not over 120°F) to dissolve salt crystals.
2. Rinse thoroughly with fresh water and towel dry before final storage.

Storage:

1. Store in a cool, dry and protected place out of direct sunlight.
2. Store separated from other dive gear as the black pigmentation of other equipment may discolor the clear silicone skirt of your mask.

Chemicals/Solvents:

1. Avoid any contact with alcohol, oil, gasoline, aerosols, or chemical solvents.
2. Do not expose any part to aerosol spray, as some aerosol propellants attack or degrade rubber and plastic materials.
3. Do not use any type of alcohol, solvent or petroleum based substances to clean or lubricate any part.
4. Do not store your equipment near any oil, gasoline, chemicals, or solvents.