Clearing Mask

[Leobendive]

This is quite intriguing as I actually advocate for using any cream or grease you have handy to help in mask sealing

I especially use vaseline or second choice a sunscreen where mask sealing is most important with rebreather diving

Interesting. Maybe it depends on the thickness of the cream. Vaseline is known to be used on sealings and is very thick. The sunscreen I usually use is very thin - add a bit of sweat before putting it on and I can feel it sliding around a bit...

 

[34109411]

obviously your mask doesn't fit you. Start with that the rest will come second nature.

mares x-mask

 

[TNEngineer]

Unshaven whiskers on male divers can also permit mask leakage. I can tell the difference if I've shaved, or not, before diving.

You need a mask that fits properly, no hair nor whiskers in the seal, and proper strap tension (neither too loose nor too tight). Experiment in a pool, you'll dial it in pretty fast.

 

[Leobendive]

This is quite intriguing as I actually advocate for using any cream or grease you have handy to help in mask sealing

I especially use vaseline or second choice a sunscreen where mask sealing is most important with rebreather diving

So I did a little Google research on the sunscreen topic. Here is the outcome:
-some say sunscreen does not interfere with dive mask sealing
-some say it does interfere with dive mask sealing (which is also my experience)
-found no recommendation to use sun screen for sealing a dive mask
-found some sources where vaseline was recommended to seal a dive mask when having a moustache or other facial hair
-Also found sources where vaseline is said to be able to damage the silicone of a dive mask (as vaseline is Petroleum based). Silicone grease should be prefered.
-of course there were also sources that state vaseline is fine to use with a dive mask.

So I think in the end it comes all down to personal experience.

One more question a little bit off topic. Why is a well sealing mask especially important when diving a rebreather? I think I understand the basic concept of rebreathers (closed circuit, co2 scrubbing, set ppo2, oxygen/diluent added to keep ppo2 stable). I don't understand why mask sealing on a rebreather is more important than on OC.

 

[inquis]

I don't understand why mask sealing on a rebreather is more important than on OC.

My take: clearing your mask will decrease the breathing (loop) volume, and adding gas to restore the volume usually changes the PO2. In practice, though, it's not an issue. You can usually tolerate a slight increase due to a tiny squirt of O2. Or if you're on deco, that increase is often desired or you need to vent anyway (from the tissue off-gassing).

 

[happy-diver]

Maybe it depends on the thickness of the cream. Vaseline is known to be used on sealings and is very thick.

Whatever it is that is thick, you can always apply thin, no globs no dollops, leaving only a film dude

The sunscreen I usually use is very thin - add a bit of sweat before putting it on and I can feel it sliding around a bit...

Well see yes I also apply it thin but in the sub tropics or in the cold I avoid adding sweat to the formula

So I did a little Google research

This is exactly what I do, even before google existed, and as shall you as you gain the decades of experience
I have be able to cite your own research and gain much great pleasure from helping yourself and the people

So I think in the end it comes all down to personal experience.

Yes but no as it depends on experience, listening skills, comprehension and capabilities

In practice, though, it's not an issue.

I would suggest it depends on whether you want to spend your time diving or replenishing
manually or listening to your solenoid doing the replenishing, and adjusting your buoyancy
etc etc etc
and then we can introduce, those that think they only exhale through their mouth, that also
exhale through their nose at the same time now theres a reason for some personal research

I didn't think I did it until I did

Rebreather divers do not inflate their dsmb with their mouths



And so now for some hands on personal research

For years I have rejuvenated old rubber scuba gear masks, fins, with Vaseline, or a petroleum lube
The people say it degrades rubber, they say it because others others say it and they like to belong

When some, rubber blends, have reached a certain stage of degredation they can not be restored

If they haven't they can, how much for how long you best try

My rubber experiments have been put aside


So now the great rubber debate in my mind at least continues now with silicone masks also orings


I have been soaking stuff in stuff for decades the only thing that is going to wreck your mask is fire
or a steamroller


A couple of my experiments

Silicone in engine oil and also in vaseline

As schmick as the day they were immersed years ago

Marks on the silicone are reflections, curvature is from the set of the rolled up sheet that I obtained them

 

[stretchthepenn]

I don't understand why mask sealing on a rebreather is more important than on OC.

What @inquis wrote, plus a few things.

Venting gas out the mask leads to changes in buoyancy. An RB diver already has an extra airspace to control, so introducing changes to buoyancy is less than desirable.

A rebreather has a finite supply of gases that's usually far less than an OC diver would carry. A leaky mask could (in the extreme) lead to running short of O2 or cutting into the bailout reserve.

 

[Ontwreckdiver]

Interesting. Maybe it depends on the thickness of the cream. Vaseline is known to be used on sealings and is very thick. The sunscreen I usually use is very thin - add a bit of sweat before putting it on and I can feel it sliding around a bit...

Do not use Vaseline, it is petroleum based and will degrade the silicone skirt of your mask. Same with sunscreen, if it builds up on the mask skirt it will make it leak. My mask that I have been using for years started to leak last year in the Dominican. When I got home, I cleaned it with sop and water and this year no leaks.
Use silicone grease, it won't harm your mask, but wash it off after every use.

 

[JonnieB]

Mask strap might be too tight - deforms the silicone and prevents it from sealing.

To desensitise yourself, go for a swim in a pool and exhale through your nose underwater while swimming.

Yep usually the case with newish divers; they think the tighter the mask strap the better the face seal and it's just the opposite. The strap should be just tight enough so the mask doesn't fall off and let the water pressure do the sealing.

 

[happy-diver]

Do not use Vaseline, it is petroleum based and will degrade the silicone skirt of your mask. Same with sunscreen,

No it will Not, and as your post shows you are talking through your hat

And that is not a good thing when all people want and want to do is help to seal their mask a bit better




Or perhaps I am speaking out of turn, and you have just missed the photo
of my silicone samples living in engine oil and vaseline for years and years

FOR ZERO ILL EFFECT

They are exactly the same as when I put them in years and years ago