Rain Covers FAQ's
W1 Are White Mountain™ backpacks waterproof?
All White Mountain™ backpack materials have a polyurethane (PU) coating
and are waterproof to varying degrees. Please visit our page on
Material Test Reports for further detail on this subject. The only true
waterproof packs are made of vinyl and have welded seams. Waterproof zips
are available, but are very expensive and can more than double the price
of the finished backpack. There are water resistant zips now available on
the market, but White Mountain™ have not approved the use of these zips
in the manufacturing of White Mountain™ backpacks.
W2 Are the seams on White Mountain™ Backpacks Waterproof?
While not entirely waterproof, all interior seams are bound with a polyurethane
proofed nylon webbing that reduces water penetration to a bare minimum.
If you think it necessary and wish to further waterproof the seams, you
can seam seal all seams with a liquid silicon seam sealer, available from
most outdoor stockists.
W3 Are Internal Liners necessary?
Some backpackers avoid external rain covers completely and use internal
liners instead. These less expensive internal liners are heavy gauge plastic
bags similar to what you'd see as a garden waste or a survival bag. Others
opt for Dry Bags, which are actually designed for canoe or kayaking trips.
The dry bags are far more durable than plastic, but also weigh considerably
more. The advantage of an internal liner? You still have ready access to
the backpack. The disadvantage? The backpack is not protected on the outside.
W4 Bivvy Bags
We recommend the use of bivvy bags in all circumstances, especially with
hiking backpacks. Bivvy Bags will protect your gear from water and allow
you to organize your backpack for ease of access. The use of different coloured
Bivvy Bags is recommended and will enable all your stored equipment to be
colour coded for ease of identification.
W5 Are Rain Covers Necessary?
Most backpacks have a waterproof polyurethane (PU) coating, that means
water won't penetrate the backpack, right? Well actually, NO! Polyurethane
(PU) coatings prevent water entering through the fabric, but don't prevent
water from getting into the backpack through the seams and through the zippers.
Bear in mind that lower quality backpacks have less stitching over a given
area, and use a inferior thread. Inferior threads are not tensioned enough
to form a tight bond on the adjoining materials, and this can easily be
demonstrated by gaps formed when gently pulling on these adjoining materials.
When fully packed a lower quality backpack will expose these gaps and allow
greater water penetration. A backpack with higher quality thread that is
stitched and tensioned to prevent gaping will prevent excessive water entering
the backpack, particularly if bound internally with a waterproof nylon tape
stitched over the exposed seam, as in all White Mountain™ backpacks..
W6 What is the correct Rain Cover Size Selection?
Care must be taken in selecting a Rain Cover size. If you strap gear
on the outside of your backpack, you'll want to make sure that the Rain
Cover will fit over all of the backpack, external attachments and all. A
generic XL Rain Cover should be large enough to cover all the gear. A personal
choice on size is one reason we do not sew Rain Covers to the backpack,
another is that Rain Covers are generally only required in severe weather
conditions.
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