How to Stiffen A Lightweight Climbing Pack

Many lightweight climbing packs come with a single piece of foam that acts like a suspension and protects your back from the contents of the pack. Packs like the entire Cold Cold World lineup, Wild Things, and MEC Alpinelite 30 and Genie come with foam backpads.

Depending on your preferences or packing methods this may not be enough support for the things you choose to carry in your pack. In my own experience, once the lid of a pack has items in it a soft pack will flop over, making packing more difficult.

There's are a few easy fixes to this problem. One is to use a framesheet from an older pack. I save the framesheets when I discard my older packs. That way I can cut or modify the sheet and aluminum stays to fit one of my newer packs. The other solution is lightweight, simple and relatively cheap. You can buy corrugated plastic and cut it to fit the size of your pack.

I have to admit this isn't my originial idea. I have a friend who's done this in the past to stiffen his CCW Chernobyl. However, when I tried to find the right material I ran into a brick wall. Corrugated plastic is hard to find. Often, you need to buy it in bulk, and when all you need is enough for one pack that doesn't make sense.

Where to get corrugated plastic

After a bit of searching I found a good source for "coroplast" in New Paltz. PDQ, a custom printing shop in the Stop and Shop Plaza, uses coroplast for custom signs and sells it for $2/foot². I bought 3 ft² for $6 and cut it to fit two of my packs. 4 ft² will easily make two framesheets with some extra just in case you make a mistake.

You can also buy corrugated plastic at Dick Blick, an art supply store that has a few locations throughout New England. If you're passing through stop by and see if they have it. Here's the information about coroplast from their website. If you mail order it you may have to buy 10 sheets of it to satisfy their requirements.

Cutting corrugated plastic to fit your pack

Once you have your sheet of corrugated plastic you'll want to size it appropriately. I did this by laying my foam frame insert atop the plastic and tracing it's pattern onto the corrugated plastic using a magic marker.

I slid the plastic sheet between layers of folded foam on the

 Ozone

Now that I have a rough idea of the size of my framesheet I can go ahead and cut the corrugated plastic. I decided to make the framesheet a little smaller than the padding. In order to protect the pack and padding I also chose to round the corners. This keeps the edges from feeling sharp and poking holes in my packs.

One final addition, that I didn't do, would be to wrap duct tape along the edges of the corrugated plastic to protect both the pack and the edges of the corrugated plastic.

Here's a link to another post about making alpine packs stiffer. Good luck and have fun!