Packing regulator with silicone grease?

[Joris Vd]

Hello guys,

I was just wondering if it's still actually considered proper practice to pack piston regulators like the mk10-5-2 with silicone grease if you're considering them for cold water diving?
My mother used to do this back in the day when there was no real notion of a 'cold water regulator'.
(she basically dove an mk2-108 combo throughout all winter and summer, later switching to mk5-109)

I can't remember where I read it. But a while ago I came across an article claiming that packing grease actually does nothing for the cold water resistance of the regulator since unless the water is literally below zero (arctic) water in the ambient chamber would actually aid warm up the air, since most of the temperature drop below zero is usually happening at the high pressure seat. Please correct me if I'm wrong, because I'm far from an expert at this field.

I have a diaphragm cold water 1st stage for general use(DS4), but I have several old mk2's, and mk5's laying around that I would love to try out.

As a guideline, the watertemperatures are around 36-43F (2-6 C)right now
So the question is basically, to pack or not to pack?

 

[tbone1004]

to pack or not to pack is up to you and whether or not they have the spec boots. Packing definitely helps because grease can't freeze so you can't turn the first stage guts into an ice cube that will freeflow which is the problem. Will that happen under normal circumstances? no, but it absolutely will at the surface, or under high load *i.e. two divers on the same first stage*.

If you have a DS4, I'd just continue using that for the cold stuff, and consider some relatively inexpensive sealed diaphragms to replace the 2/5's if you need them for real cold water