Today I discovered where I draw the line for diving without liners in my 720s.
4 degrees celsius is not a comfortable temp to dive without a liner!
We had 6-10 degrees a bit closer to the surface and that was pretty much the limit for what I could manage.
Will definitely invest in a pair of liners before going back there!
Yep - that sounds about right for me too. Anything below 50 deg F I'll add a liner for the additional warmth. Anything higher than that and I forego the liner (underglove) for the additional dexterity and tactile function.
That's not possible with PVC or latex ("rubber") gloves, as they require undergloves for warmth even in 70 degree water.
Throughout all temperatures, I find nitrile 720s are warmer, thinner, more dexterous, and more reliable than either PVC or latex gloves when undergloves are taken into account.
SRSLY, who's diving drygloves without liners? Before reading this thread, I wouldnt have imagined that anyone would do that. To me, it'd be like diving a trilam without an undersuit.
Yeah, and the "standard" of ALWAYS wearing undergloves under your drygloves is going to be a tough one to catch on... But technology advances and material science moves forward... VERY slowly in the drysuit market, since they're relatively uncommon compared to wetsuits and last for decades. The last time I looked, there were only about 3,500 drysuits sold globally annually... The majority market share leader (DUI - as of 2016) only sold about 1300 suits for the entire year.
Your comparison of not wearing an undergarment under a trilam is accurate. Most trilaminate drysuits are waterproof because of a butyl rubber layer of material sandwiched between two layers of fabric, like ripstop nylon, Cordura, spandex, and more. Butyl rubber has virtually no insulative properties to it at all, and neither do synthetic fabrics like polyester, nylon, and acrylic that makes up trilaminate. Fact is - the butyl rubber core of a trilam is virtually identical material to a latex dryglove like the ones made by SANTI or the G17ks. Without an undergarment or underglove, butyl rubber (aka "latex") is cold and clammy against the skin and makes for a very chilly dive - even in waters as warm as the mid-70's F.
Nitrile, on the other hand, has much better insulative properties, and can be used with a lot less insulation and yet still maintain warmth. I've found that they work great and keep my hands warm all by themselves ("undergloveless") down to about 50 degrees F... And anything lower can simply be bolstered by what I would normally consider a warm-water underglove. The 720s are just warmer overall.
...Which means that in practical, daily use, the stand-alone nitrile 720s are thinner and more dexterous to use than a latex glove equipped with an underglove... Even though latex is thinner and stretchier.
...And nitrile gloves like the 720s are LOADS better than thick, stiff, PVC gloves equipped with an underglove.
...And the 720s are MUCH tougher than either... Which is completely counterintuitive.
My 720s do not have a pleasant smell after some 40 dives now, but its a small price to pay for the dexterity you get.
Pretty much everyone I have dived with this year has been baffled that I dont use a liner, "your hands must be freezing!"
No, they are not because nitrile is amazing
At 40 dives - and at roughly $7 per pair, I'd just go ahead and replace them... But if you don't want to do that, you can wash them out. The acrylic liner inside the gloves takes to washing very well.
Just fill the gloves with soapy water and slosh it around. Rinse well and then turn them inside-out to dry (can't do THAT with PVC). They'll dry within an hour or two (PVC never really "dries") and don't even need to be removed from the rings if you don't want to. The acrylic liner inside the glove comes very clean quite easily - much better than cotton-lined gloves like the G17ks, 620s, 660s, 495s, etc. because acrylic "wicks" instead of "absorbs" like cotton does.
I am researching how to manufacture a trilaminate drysuit using nitrile instead of butyl rubber. Stay tuned.
Meanwhile, the closest thing to it is the new BARE Sentry/Guardian hypercompressed (not "compressed") neoprene drysuit, which is something that I've been helping to design for the past two years.
Alas, that's another thread.
Material science is amazing.