Wednesday, 15 August 2012

How to Stiffen a MEC Alpinelite 30

Many of the smaller lightweight packs on the market these days don't have framesheets.  If you buy a pack with a framesheet, the lightest you can go is around 1 kg, whereas "soft" packs generally can be around 500-700 grams.  When you're shedding weight that's big enough to make you favor the soft pack.  Until you cram it full of climbing gear and realize that it carries like a piece of sh!t.

Common packs like this are the MEC Alpinelight 30, Arc'teryx Cierzo and the Deuter Freerider.  They use foam rather than a stiff plastic/metal sheet to "stiffen" the backpanel of the pack.  This works fine when you just have a sweater and water bottle in your pack.  Fill it with a trad rack, hammer, pins, helmet, rope, emergency gear, etc, it suddenly carries like a piece of crap, your hammer pokes you directly in the spine with every step, and you spend all day cursing your weight-saving efforts.

Despair no longer!  For about 5 bucks, you can easily rig up 4 packs to have nice, firm "framesheets" which weigh no more than a few grams.

What you'll need:

  1. Small Sheet of Hollow Polypropylene Sheet.  Commonly found in hardware stores in 2 x 4 foot sheets for around 5 bucks.  It might be labeled "Tenulite" or similar.  It should have a rectangular grid when you look at the inside.  This is enough to do about 4 packs.
  2. Small Saw
  3. The foam back panel from your pack.
How to rig it:

I did this to my MEC Alpinelite 30 (Long Size).  It has a pocket in which the foam is slid.  This is a common feature, as manufacturers advertise this pad as a nice seat for taking a break on.  It really never works that way, because as soon as you take the pad out, your gear smushes into the empty space and replacing it is impossible.  But I digress...

This might be doable on a pack lacking the pocket for the foam.   If your pack has a hydration sleeve, the Tenulite could be slid in there, but I'm guessing that it would be sloppy and not as rigid as my setup.  You could also sew a sleeve for the tenulite, but that requires more effort.

  1. Take out the foam back panel, and using a Sharpie, trace its outline onto the Tenulite.
  2. Cut the tenulite slightly smaller than the foam pad.  The extra space that this Tenulite consumes will make the fit tough, so going a bit smaller is a good idea.
  3. Put the Tenulite into the pocket first, followed by the foam pad.  Put the foam towards the wearer of the pack so that it provides some comfort.
  4. Close the pocket, load up the pack and test the fit.  I almost guarantee that you won't go back.
The Tenulite is the red, hollow plastic sheet.  The stock foamie is the grey thing below.  The pack is fully loaded with gear for an alpine rock climb, and carries like a dream.

For 5 bucks I got this whole sheet.  The missing portion is what my Alpinelite consumed.  Could do 3 more packs easily.

With my experience, this stiffened my pack to the point that it carries better than my Alpinelite 45!  It's real darn stiff, transfers load super well, and weights essentially the same as the stock pack.  It's still comfy because of the foam.

Bonus:  Tenulite is actually used in many lightweight leg splints.  Manufacturers essentially take the plain board, glue some velcro on, and call it a splint.  So if your buddy takes a nasty slip and breaks his tib/fib, whip this back panel out and with a few prussiks/triangle bandages/rope/sling/whatever, you have a pretty stable leg splint.  Huh!

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