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Sleeping Bags
For some people a sleeping bag is just something
constrictive they sleep in away from home. For others it is a treasured
possession, the thought of which sends our minds spinning about far away
places, and sifting through dramatic or exciting memories. It is our pleasure
to bring you the range of Macpac, Mont, Mountain Equipment, and Mainpeak
sleeping bags, and to give you a few hot tips on getting the most out of your
bag.
Fillings
Down lasts longer when looked after. Over time the materials in
synthetic sleeping bags, such as Hollofil, and Quallofil, will compress and
seperate, losing some of their capacity to insulate. However, if down is well
maintained, it will loft to near its original capacity for many years. This
means that over time, down will continue to trap more air, and remain a better
insulator.
Down is lighter for the same warmth. Despite all the advances in
synthetic fibre technology, natural down is still a far more efficient
insulator than its synthetic counterparts. It is lighter for the same warmth,
and less bulky.
Down bags are harder to look after. Down filled bags require a lot of
care. You should do everything you can not to soil the filling. You should
always use one with a liner, as body oils will reduce down's insulation
capacity, as will any other dirt or grime. Washing a down bag also requires a
good deal of care and attention! (see below). A synthetic bag, however, may be
washed regularly (with care), and dries quickly.
How down fill keeps you warm. The quality of a down fill is measured on
a number of levels. Firstly, the proportion of down in the fill. Some fills do
not contain 100% down, because it just isn't necessary to achieve the warmth
some bags require, so a down/feather blend is used instead. The second is the
quality of the down. The standard measure for this is called a loft rating. It
is measured by weighing out one ounce (28grams) of down, putting it into a
cylinder, and then measuring its unrestrained volume in cubic inches. Thus a
loft rating of 700 means that one ounce of the down will expand to occupy 700
cubic inches (11.5l!). It should be noted that even in the very best downs,
there will occasionally be 'pin' feathers. It is impossible to separate these
from the down, except by their occasional appearance through seams in finished
sleeping bags!
Synthetic bags are warmer than down when wet. So who wants to sleep in a
wet sleeping bag? Nobody but you may not have the luxury of choice. A large
proportion of the air trapped in synthetic bags is contained in the microscopic
tunnels in the synthetic fibre filaments. Thus when a synthetic bag gets wet,
water can only occupy a certain amount of the space normally filled by air, and
the insulation remains at least partially effective. There is no such
partitioning of air in down, and water may invade all of the places that would
normally trap air. The only way to prevent this from happening with a down bag
is to cover it with something waterproof and breathable, be it a Gore-Tex bivvy
bag, or a Hydronaute XT shell (see below).
How synthetic fill keeps you warm. Synthetic fills are usually comprised
of polyester fibres of varying sophistication. One of the most important
features that distinguishes between performance of different fills is the
number of cores within individual fibres. A fibre that contains only one core
will not trap as much air, and therefore not be as efficient an insulator as a
fill that has 7 cores per fibre.
Washing
Down Bags
Always wash a bag according to its manufacturer's instructions. However,
generally:
Run a shallow bath of luke warm water, and dissolve in it the recommended
amount of an appropriate down wash.
It is important not to use any old detergent, as it will probably strip the
down of its natural oils, something which contributes to its insulating
efficiency.
Gently knead the bag to wash thoroughly. It is crucial that you never lift the
bag while it is wet. The wet down is heavy, and it will more than likely tear
the fine mesh internal baffles that separate your sleeping bag into
compartments. Hold the sleeping bag at one end of the bath, while you let the
dirty water out at the other. With the bag still in the bath, refill the bath
with enough luke warm water to cover the bag, and rinse it. Empty the bath
again, and repeat rinsing procedure until water is clear.
Without lifting the sleeping bag, transfer it into a tub big enough to contain
it, and from the tub transfer it into a washing machine bowl.
Now slowly spin it to remove as much water as possible. You may now pick up
your bag carefully! There are two ways of drying it. Traditionalists will hang
their sleeping bag in the shade somewhere warm and dry, and probably breezy,
and over the next two or three days will spend many hours shaking the clumps of
down apart. Technoheads will simply pop it into a tumble dryer on a medium heat
setting, along with a pair of clean sandshoes, or even tennis balls to help
break up the clumps of down.
Yes. Washing a down sleeping bag is a labour of love(?), but often a rewarding
and nostalgic one. If you do it right it will loft well, smell nice, and
continue to be a treasured possession for a long time to come.
Synthetic Bags
Always wash a bag according to its manufacturers instructions. However,
generally, a synthetic bag can be washed by hand in the following way:
Predissolve a mild detergent in a large tub or bath, using warm water. Knead
bag to wash thoroughly.
Transfer to a washing machine, and, on a gentle or slow setting, spin the bag
to remove the water.
Rinse thoroughly, and repeat spin to remove excess water.
Hang in the shade to dry.
Alternatively, take it to the drycleaners, but make sure they know how to do it
first.
Design
Tapered Rectangular
These afford a generously cut bag with room to
toss and turn, without becoming entangled. The bags will also unzip readily to
form a quilt, and can for this reason be used over a broad temperature range.
Mummy Conversely, the contoured mummy design
maximises thermal efficiency, and minimises weight and bulk, so they're quite
snug.
Shell and Fabrics
Most shells and linings are nylon based Usually a light and soft nylon fabric
is used as a lining because it doesn't contribute much weight to the bag, and
is down proof, so that it will prevent down from 'leaking' out.
Shells tend to be a little more durable to withstand the rigours of backpacking
and travelling, and are commonly slightly heavier nylon fabrics. If
waterproofness is a criterion for selection, then you should choose a shell
constructed from Hydronaute XT. This is an extremely light, waterproof,
breathable, and windproof fabric for applications where there is a likelihood
of extended dampness: for example, snowcaves. Dryloft shells contribute
substantially to the warmth of the bag because it has a propensity to trap warm
air around you, so preventing heat loss. Dryloft also assists the transport of
moisture to the exter
Warmth Ratings
Arguments have raged about the methods for classifying sleeping bags as
suitable for particular purposes and people. Some rate by temperature, eg 0 to
-5, but this scale risks overconfidence in the bag's capabilities to insulate,
given that there are so many influences over sleeping comfort. What are they?
You may well ask!
Gender Most women seem to require warmer sleeping bags than most men for
the same external conditions because of the difference between metabolic rates.
Diet What you have eaten during the day will dramatically effect your
sleep. If you haven't eaten enough to replace the energy used, you will not
have the same capacity to generate heat, and will sleep colder.
Activity You are likely to be warmer at night if you've spent the day
resting and eating, than if you have been slogging it out climbing or skiing in
a blizzard.
You Your shape, physical condition, and metabolism all effect your
sleeping comfort.
Moisture If your sleeping bag is damp from extended use in a snow cave, or
soggy tent, then it will not insulate you as efficiently, and consequently,
will not keep you as warm at night.
Ground What you sleep on is crucial. It is pointless buying a warm
sleeping bag and then not insulating it from the ground. Use an effective
mattress.
Clothing Wearing insulative clothing, especially on your head, hands and
feet, to bed will increase the temperature at which you sleep.
Preparation It is important that you give the bag a good shake, and let
it fully loft before climbing in, so that you can be sure that the down is
evenly spread, and that there are no cold spots.
A reliable method of rating sleeping bag is by taking an holistic approach, and
ascribing end uses eg Ski touring, Bushwalking et cetera to the bag.
The fundamental problem is that we're all different!
If you're a warm sleeper, that is, cold conditions don't bother you so much,
then buy a bag for conditions that coincide with the given end use description.
If you think that you're a cold sleeper, then buy the next bag up in the range.
eg You've decided to buy a Specialist Box Foot bag that will keep you warm when
you're ski touring. If you're a warm sleeper you'd probably want the Spindrift.
If you're a cold sleeper, you might want the Telemark, or a Dryloft Spindrift.
Simple huh? No not really. If in doubt discuss it at length with a staff
member!
Storage
Always take your sleeping bag, down or synthetic, out of its stuff sack while
it's not being used. Either spread it out and use it as a quilt, hang it up, or
put it in a large mesh storage sack. This way the bag will not lose its
insulative efficiency from extended compression. However you choose to store
it, it should be somewhere well ventilated and dry.
When you pack your sleeping bag into its stuff sack, just shove it in; if you
have a Dryloft shell, turn your bag inside out first - you'll find it much
easier. You should not fold a bag in half and then roll it. This puts a great
big cold spot right down the middle of your bag, especially in synthetic
sleeping bags.
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