Delamination. The fabric is coated with a substance (probably poly) that makes it water resistant and/or helps with the structure of the fabric. You lost a little water resistance but other than that it’s fine. Don’t let it get soaked, or use a liner bag. Whatever is inside will get damp in rain.
@Skyler
Thanks I’ll let her know it’s still fine to use, preferably on sunny days!
Avery said:
@Skyler
Thanks I’ll let her know it’s still fine to use, preferably on sunny days!
You can rub beeswax on it
Avery said:
@Skyler
Thanks I’ll let her know it’s still fine to use, preferably on sunny days!
You can rub beeswax on it
You can put your weed in it.
Avery said:
@Skyler
Thanks I’ll let her know it’s still fine to use, preferably on sunny days!
You can reapply the water resistance… look up “reapply DWR backpack” and you’ll find a wealth of info
Waterproof (or at least water resistant) coatings peel off over time. Google it if you want to see examples. Can be a bit messy but fine to use.
Axel said:
Waterproof (or at least water resistant) coatings peel off over time. Google it if you want to see examples. Can be a bit messy but fine to use.
Thanks 
How old is this pack?
If it’s 8+ years - then I’d look into ‘delamination’. The nylon fabric is separating maybe.
More likely its the Polyurethane coating peeling off. It will hydrolyze with age or if packed away wet. PU is good for waterproofing nylon fabrics but doesn’t last forever.
I had a bag do this despite never being stored damp.
@Crosby
You’re right about polyurethane, but not all types of PU. The other aromatic urethane, polyether, doesn’t hydrolyze like this, but it does turn yellow.
@Crosby
Tyvm!
DEET melts plastic. If you guys use a fair amount of bug spray, it could have done the damage.
Winter said:
DEET melts plastic. If you guys use a fair amount of bug spray, it could have done the damage.
This is what I ran into and it’s no joke it melted my headphones
Winter said:
DEET melts plastic. If you guys use a fair amount of bug spray, it could have done the damage.
This is what I ran into and it’s no joke it melted my headphones
It rusts metal like no other too
@Hale
I did not know that, interesting….
Winter said:
DEET melts plastic. If you guys use a fair amount of bug spray, it could have done the damage.
This is what I ran into and it’s no joke it melted my headphones
Melted the clear coat and paint off of my zippo one summer.
Winter said:
DEET melts plastic. If you guys use a fair amount of bug spray, it could have done the damage.
DEET ruined my best toiletries pouch and its contents.
Switched to picaridan/icaridan based sprays
Put it in the washer on a cold delicate cycle. Then hang it up to dry. If the white bits are still around after it’s dried, then it’s likely the water proofing material. If it’s gone, then it may have been either mold or something that spilled and dried on the bag. Which makes sense as it’s on the zipper too.
@Kirby
Tyvm