It happens to everyone: you've had your favorite backpack for years. It's held textbooks, a week's worth of clothes, and camera equipment. You've dragged it on and off of trains, planes and automobiles; you took it caving and scraped it against rock walls. Its limits were tested and it always stood up to the test, until one tragic day when the zipper split.
Working at the Summit Hut, I've seen the stricken faces of people bringing in beloved jackets, sleeping bags and purses, hoping someone can repair the defunct zipper that keeps separating after the item has been zipped up. Turns out this is usually an easy repair you can perform in seconds with a simple set of pliers. Here's how to diagnose your zipper problem and get you favorite backpack up and running again.
Take a careful look at the teeth of the zipper. If any of the individual teeth are missing, or if the taping fabric next to the teeth is torn, you'll have to send the item in to the vendor or find a seamstress to replace the zipper itself.
If the zipper's teeth are intact, that means the problem is with the zipper's slider, and there are do-it-yourself solutions to that. Start by tightening the slider.
The slider is essentially two channels that come together, pulling the zipper teeth in and pressing them together. Well loved and well worn zippers sometimes loosen up from top to bottom, so they don't put enough pressure on the teeth to lock them together. To tighten the slider, first unzip it all the way to the bottom, making sure that the slider is sitting squarely on the bottom of both sides of the zipper. Take a pair of pliers and clamp them, top to bottom, around the slider on one side of the zipper pull. Squeeze with a medium-firm pressure, enough to feel a little bit of give in the slider but not so much that you press it closed. Repeat on the other side of the zipper pull. Then try zipping it up.
If the zipper works a little better now but still separates somewhere, it just needs to be tightened a little more. Repeat instructions above. It's possible to clamp the slider down too much and the zipper will be a little stiff; just keep working the zipper back and forth and it will loosen up a bit.
There are a few rare instances where the slider is completely worn out and needs to be replaced. In that case you can get a handy-dandy Zipper Rescue Kit that contains every common zipper slider size known to the outdoor industry. Now you need to get the slider off, which on jackets and sleeping bags is pretty easy and on other gear will likely involve a little sewing. On jacket zippers (or any piece where the sides being zipped up totally separate at the bottom) the only thing keeping the slider in is a little metal stopper pinched into the bottom. Use your handy pliers (or possibly a combination of implements found on a multi-tool) to open up this stopper and pry it off the zipper. Then slide the old slider off, slide a new slider on, and get a new stopper from the Rescue Kit to fasten on to the bottom with your pliers.
If the zipper is sewn into the recesses of seams in your backpack or tent, you'll need to pull out some of the stitching around the bottom of the zipper to get at the stoppers, which you can then remove and replace with the same instructions above. If you're not handy with a needle and thread, you might want to get a seamstress to take care of the sewing back together. If the item is waterproof, beware that water can seep through the new stitch holes and you might want to get some waterproofing tape to stick over it when you're done.