Chemical Handwarmer with Drysuit?

[DanL]

Anyone ever try the chemical type handwarmer/footwarmer packets in a drysuit?
I'm referring to the ones that you open, expose to the air, put in your pocket,gloves or boots and they start to warm up and stay warm for a couple hours.
I know they won't work totally wet, but in a drysuit - 2 to 4 of them tucked in the undies - they should stay dry and generate heat.
Guess my biggest question is do they get too hot at depth where the O2 partial pressure starts getting high.
Would they work????
Thanks,
Dan

 

[Stone]

There is another type of hand warmer that my wife and I have used in wetsuits.

This hand warmer is crystline until it is boiled for 20 minutes, at which time it becomes liquid. It remains liquid until you activate it and it turns into mushy crystals (which causes it to give off heat)

Here's the link Reheater Heat Packs

 

[Arduous]

Yes they do work in a dry suit. I have used the chemical hand warmers in my dry gloves during early spring and dead of winter dives here in New England. I use a thin glove liner and put the heater between the liner and the dry glove. I don’t think I would want to put a heater somewhere else on my body in a dry suit. I think you might be asking for problems there. Like over heating or possibly an uncomfortable burn, should the heater slip onto bare skin........................Arduous

 

[BlueDolphin]

I was wondering about these as well. I know they will burn if they stay against the skin. But wondered how they would do in a pouch or pocket.

They come in varying sizes..... perhaps some experimenting with the smaller ones.

I was curious if the chemical reaction would damage the suit/seals etc..

 

[rcohn]

I've tried the warmers you expose to the air in dry suit boots. I find they don't work, not enough air for effective heating.

I use the crystalline type in my dry gloves when it is below 40 degrees F. My hands get cold easily. They would burn the back of my hands, but the palms are much less sensitive. They feel odd at first, but the fingers have full dexterity.

Ralph

 

[disco1999]

Someone just got his feet burnt to the 2nd degree while diving in a drysuit under 100' in cold waters. As the partial pressure of oxygen increases inside the suit, the pads get warmer, the diver had to flood his drysuit to cool the burns. Beware. DON'T USE CHEMICAL HAND WARMERS INSIDE A DRYSUIT AT DEPTH. There is usually a warning on the package of those products not to use those in a rich oxygen environment.

 

[fmerkel]

Had a friend that put them directly on his skin (calves, try to alleviate cramps). At depth they went into overdrive and burned him by the time he could get out of the water and get them off.
Not sure how hot they would get if placed a couple layers out. On the complete outside of the insulation not sure if they would do any good, just heat the water.

 

[stuartv]

Use the sodium acetate ones. They are reusable and they don't react to oxygen, so they are safe in a drysuit.

 

[Gareth J]

I would strongly advise against having chemical warmers inside a suit.
If you are intending to use an artificial heater, then it should be possible to disable it in water from outside the suit.
Personally I could only ever advise an electrical heating system powered from outside the suit. In the worst case, if you can't power down, then you can always cut the lead.

Interestingly, at the Diving Officers Conference in the UK (BSAC DOC), the decompression specialist where urging caution over the use of heating systems. I believe there main concern was divers being warm at the start / mid section of the dive, and then cold after the heating system failed in the later part of the dive.
There advice was to use the heating at the end of the dive to aid off gasing, rather than the start, which promotes on gasing and off gasing suffers if the heating system fails and the diver becomes cold during the decompression phase of the dive.

Gareth

 

[KenGordon]

Diver suffered chemical burns in freak accident 160ft below sea level | Daily Mail Online

Sorry about the Daily Mail link, but it has the pictures that should scare you off using chemical heaters.

A quick google will show something like this happening every few years. I am not sure that avoiding a rich mix for your suit inflate gas will fix it either. They will be designed for a ppO2 of .21 bar, at 30m, best case on air, it will be subject to .84 bar, so is very likely to run faster than designed.

As Billy Connolly put it, "There is no such thing as bad weather, just the wrong clothes."