So I have just been mulling over what to "tweek" this year heading into canoe season and I had a random thought.
One of my more annoying occurrences in the boundary waters is when my day pack (backpack) that I keep at my feet gets VERY wet on the bottom from water inside the canoe.

I want it handy with all these things within my arms reach:
rainsuit, fishing tackle, sunglasses, sunblock, bug spray, snacks, water bottle
so on and so on

I get annoyed when it gets wet for on a portage or it just gets wet and stay wet for a while. It stands pretty up right on its own. I do use a strong trash bag on the inside to keep things dry and it works pretty well.

I have also used a large sponge that I take with me on trips to soak up the water before my bag does, then just ring it out. Works pretty well.

Well, anyway, on to my point. I dont have any experience with Flex Seal (and if I decide to try this it will be with an old bag 1st) but I am wondering about coating the bottom and up about an inch or so with Flex Seal, 2 or 3 coats, to try to keep out MOST of the water. Definitely the stitching as well.

Does anyone have experience with this product?
Do you know if it works on fabric?
Is it worth the time and money to try it out?

sorry this is long, just wanted to explain my thinking,
thanks in advance.

I have used it on canoes, but I don't think it would work on a pack, but may be wrong? I would think it would crack and peel?

I would try "Never Wet" first. Never Wet

Do realize the rubberized bottom of the pack will catch and hold any moisture that does make it's way in. Your fix may be worse than what happens currently.

butthead

Have you considered switching to a drybag?

Small garbage bag inside the pack will do the trick also

quote ozarkpaddler: "I have used it on canoes, but I don't think it would work on a pack, but may be wrong? I would think it would crack and peel?
"

I'm in this boat. Hah. I would think that it would crack and peel from use. Although I see it advertised it won't. Have you found for less than the $40 on their website?

If I understand correctly the contents stay dry but the pack material gets soaked.
What material is your bag made of? What about just waterproofing with canvas wax or a silicone based application? Or stitch on a piece of waterproof material for a bottom? Or make a little removable "bucket" that could be held to the pack with little bungees so you take it off and let it dry if water does get in from the top.

quote walllee: "Small garbage bag inside the pack will do the trick also"

He does that already. He doesn't like his pack getting wet though.

What would be a neat answer to your question is if you could find a way to have your pack dipped in nitrile like many gloves are.

What about sewing vinyl "fabric" onto and around the bottom of the pack?

Maybe PlastiDip would work.

Permatex flowable windshield silicone can be brushed on, is cheap. Could thin it more with mineral spirits.

Daniel

I also use a small garbage bag inside my day pack. Works great and is an inexpensive alternative to a new bag, or Flex Seal treatment.

This winter I waxed a canvas mechanic's bag that I use as a tackle bag for the same reason...it gets wet and stays wet while on the bottom of the canoe. It was simple to do and might work for the lower part of your pack.

I'm in the dry bag camp. For your pack I agree with Canoe42. Thin down silicone and treat the inside of the bottom of the day pack. This is the cheap fix for leaking tent floors so I'm confident it would work on the inside of your pack as well. Personally, I would be concerned coating the bottom of the pack on the outside as silicone stays fairly soft and flexible when fully cured and the bottom of any pack experiences a lot of wear and abrasion that would damage the silicone seal. Gear Aid DWR the outside of the pack to keep the pack material dry-ish. Results may vary.......

I would thin down silicon and put on the outside if you do not want the fibers of the cloth to soak up moisture. Or Spray heavily with a DWR to keep moisture from soaking into the fibers. Many things in the weeds as what kind of fabric- material previous treatments and or coatings. Many options before I would consider flex seal. Appearance of the product is a definite possibility- outcome.