Re-waterproof an old backpack?

[Bengo]

Howdy!

Longtime member here. Looking for a advice about refurbishing my old Lowe backpack. I see, on the inside chambers of the pack, that what I take to be the waterproofing "skin" is flaking and peeling off the fabric. A thin, white-ish, plasticky residue is rubbing off the walls. IS that indeed the waterproofing? Can it be replaced/rejuvenated? Hate to waste a perfectly good pack, though I suppose I could keep it for fair-weather use only.

Thanks for any suggestions!

Inside of top flap, Lowe Alpine.

Ben

[REI-JohnJ]

@Bengo 

Hey there, Ben!

Thanks for bringing this question to us here in the community! While it is hard to tell what was used to add water repellency to your backpack, it is likely a polyurethane (PU) coating. As such, your best bet is to use rubbing alcohol and a soft brush or rag so remove the residue. As always, start with a small section to see if it works before moving on to the rest of the pack. This is the process for removing PU from tents, as described in this Expert Advice article, How to Waterproof a Tent. You could also use a vinegar/water mix to do this as lined out in this conversation Replacement Rain Fly Half Dome 2 plus. It's important to remember that this worked well for a tent because the user was able to rinse it clean in a washing machine. A backpack with an internal frame will be challenging to rinse clean and eliminate the vinegar smell.

When you're looking to re-apply a treatment, we recommend a product like Nikwax Tent and Gear Solarproof waterproofing spray.

Hopefully this helps revitalize your backpack and you get many more miles on the trail with it. Thanks!

[Cdawley4]

Not sure if that is waterproofing, though, seems you could use a hair dryer and a hard bristle tooth brush to scrub the old waterproofing off, them spray new waterproofing onto it, then using a vacuum cleaner to get the loose particles that fall inside the bag.

My fear is that over time, those flakes would eventually flake off and get all over your gear inside the bag and cause a headache you may not want, if hiking out on the trail or wandering about while using the pack.

[hikermor]

This peeling of the waterproof layer has eventually occurred with every pack I have owned with that feature (at least ten or so).  In every case, I peeled off the crud and continued to use the pack without any problems.

No pack is totally waterproof, although there are roll top closure dry bags that wll totally seal out moisture.  I have used those to keep my pack dry when it was shipped on open deck boats for significant passages.  For items that must be kept dry (down sleeping bags, etc) seal them is plastic sacks within the pack.  I have never experienced a rainstorm that significantly wetted my gear and what leakage occurred was through the necessary apertures in the pack - zippers, etc.

Waterproof  pack fabrics are an insignificant issue.

[Bengo]

Thanks to REI-JohnJ, CDawley4, and hikermor for your responses. It sounds like less of an issue than I had feared. Yes, I believe I will clean it off, trying rubbing alcohol and/or vinegar and a brush. Good thing I obsessively save old toothbrushes for such cleaning projects! I've lugged this beast around for many years, may as well keep doing so!

Thank you all!

Bengo