Saturday, December 26, 2009

Re-waterproofing a backpack

Do you have a trusty backpack? Because I do. It goes everywhere with me. Work, travel, play, outdoors. It holds my computer, or it holds my passport, or it holds a light jacket when I'm out on a day hike. It's a North Face Hot Shot, and it's about 8 years old.

Soon after some heavy traveling, I noticed white flakes appearing on all of my gear I stuffed inside the bag. Upon further inspection, I noticed that the waterproof coating on the inside of the packcloth was actually peeling off, making the bag pretty much useless in any sort of drizzle or downpour. But I couldn't give up this pack, it meant too much to me.

After some research, a local REI sales rep recommended McNett's Tent Floor Sealant, a water-based urethane coating that you paint on with a foam brush. I have no idea why it's called "Tent Floor Sealant" when it has so many applications, but it did the trick. Here's a short description on how to apply it, just in case you run into the same problem.

1) Peel off excess waterproofing (this part take forever). Tip: it helps if you wet the surface of the pack. Let the pack dry completely.

2) Lay down a work surface, since the sealant is quite liquidy, and it tends to drip when applying. I cut up a paper grocery bag and laid it down on the floor.

3) Liberally squeeze the sealant onto the included foam brush and paint onto INSIDE of the pack fabric. Make sure to coat underneath the zipper flaps.

4) Hang and let the coating dry for a day or two. Reapply if you want an extra level of protection.

Available on McNett's website and at REI for $10.

Update 1/24/10: I've noticed some very slight darkening on the top section (it looks like faint rubbed-in dirt) of my backpack after re-waterproofing. This is probably due to the amount of sealant I coated the inside with; I put enough on to the point of saturation. If you have a light colored pack and don't want this to happen, don't quadruple coat when you're waterproofing. :)