Materials Used - Sleeping Bags for Camping
The key components of a sleeping bag are:
- its Size and Shape (see Types and Styles);
- its Outer Shell (the outside of the sleeping bag);
- its Fill (the crucial component that actually keeps you warm);
- the Zip/Opening,
This is typically based on a tightly woven synthetic fabric with a durable water-repellent finish (DWR). The water and wind resistance are determined by the tightness of the thread weave in the fabric.
Sleeping bags where there is any evidence of leaking fill should be avoided, as the thread weave is too loose.
Ripstop nylon/polyester is now frequently used as it has thicker threads woven into the fabric to increase its durability.
Gore-Tex® can be used but this is often replaced by Dry-Loft (also from Gore) because, although less waterproof than Gore-Tex®, the breathability is much better.
For this reason, Dry-Loft is a good choice if you need some water-proofness as well as breathability.
Microfibre provides the best breathability so this is the best choice if you don't plan to use the sleeping bag in damp/wet conditions.
This is the business end of a sleeping bag. The insulative material (that actually keeps you warm) is packed between the Shell and the Lining and kept in place using devices such as baffles (seams that run across the sleeping bag to stop the fill moving).
There are two main types of insulation:
- natural (from goose/duck) down or
- an increasing array of synthetic materials such as Primaloft or Polarguard.
Down provides the best overall warmth/weight ratio. It is also more durable and breathable than synthetic equivalents. However, if it gets wet it loses most of its warmth and almost doubles in weight - and takes a long, long time to dry out.
In contrast, whilst synthetic materials tend to be heavier and bulkier than down of comparable warmth - they will retain most of their warmth even if wet and will dry more quickly.
Neither do they require as much maintenance (eg airing after use) as a down sleeping bag. The technology being developed by the fibre manufacturers is improving all the time producing fibres that are getting close to matching down for warmth/weight ratio and compressibility.
A two-way zip is preferable as it gives you more options for ventilation. Most sleeping bags these days have an insulated flap (or baffle) over the zip to prevent heat loss.