How to protect stitching on bottom of pack?

I usually pretty heavily Seam Grip all of my pack seams on bottom edges, strap connection points, and high-wear areas, reapplying a layer every season or so.

same here, seam grip

store the left over tube in the freezer, it will keep for years.  Outside of freezer it will keep for months

Could you do sort of a bathtub bottom design to raise the stitching a bit? I would still apply seam grip.

For disclosure purposes, my DIY skills are limited to stuff sacks…

If your stitches are on the bottom and you cover with seam grip it’s quite robust. Maybe if you were rock climbing and trying to scrape off, but you’d really have to work at it

Thanks, everyone for the Seam Grip tip!

I’m putting in a vertical inner divider, so the bottom of it will be inside the pack bottom’s perimeter, therefore it’ll be exposed to the ground (when standing up).

What about sewing the divider to a “false bottom” and then sewing that false bottom inside the pack? Basically just doubling the pack bottom and having the stitching on the inside layer.

Also check out Hanchor pack designs–they sew in a webbing rim around the bottom of their packs that touches the ground and keeps the bottom fabric raised up.

Would your divider work if you only sewed it to the front/back walls, avoiding the bottom?

Greg—A second bottom layer might work, but the sewing sequence is already complicated. I’m not sure I could figure that out. :)

The Hanchor bottom rim holds the pack upright nicely, but it seems a bit heavy and unslick to me.

Rene—I’ve thought about leaving the bottom loose. I’d rather not—I want to be able to put small items in one compartment with confidence that they won’t migrate to another.

glue Velcro to the pack bottom, sew a mating strip on the lower end of the divider.

Chris R—Thanks for the idea. I think if I can successfully glue Velcro to the bottom I’ll just glue the divider to the bottom directly. :)

More:

Put a stretch mesh pocket under the bottom of the pack; this will protect a bottom seam.

Instead of trying to make a second bottom layer inside the pack, do it outside: sew in the divider with a bottom seam, and then add a burly second layer to the outside of the pack. (Granted, the rest of the assembly may rule this out.)

Use two narrow, waterproof pack liners, one for each side; don’t sew the bottom seam.

If you glue it, remember to sew a flap on to the bottom edge so you have a T shape to glue – this will avoid peeling the bond.  Pending material, tape may also be an option.

Rene—Thanks for the ideas. The bottom pocket thing doesn’t appeal to me: the bottom gets the most wear, so I want a durable material there, it would get dirty and maybe even muddy, and I don’t feel the need for that kind of pocket use. HYOP(ocket)

I’m going to try gluing a couple of pieces of scrap material, let it set up, and then try pulling it apart. I’m thinking of using Gorilla Glue (made of polyethylene like the Robic inner coating).

Gorilla Glue is not polyethylene; it is polyurethane.

Cheers

Roger—Oh, my mistake. I meant to say Gorilla Glue is polyurethane—which sounds like a good choice since the Robic nylon has a PU inner coating.

Very good adhesive, PU.

Cheers

I sew on the pack bottom panel with all the stitching on the inside.  Like on the inside of kid’s doll.  Two lines of stitching with a tough thread, but the seam allowance and thread are exposed inside.  Don’t use basting tape inside, but do seal with PU as suggested, and sew a 2-3 oz and very water and abrasion proof nylon onto the seam allowance on the inside.  Use 6 oz diamond ripstop on the outside, and something  like RBTR’s 2-3 oz hex nylon for the inner layer.  These are heavy fabrics, but for just a pack bottom don’t add much weight, and make the pack bottom pretty impregnable.

Sometimes the inner bottom is just sewn to the seam allowance on the inside and sealed.  A neater way is to leave the rear side of the pack that touches the wearer’s back open until last.  Sew the inner bottom to the outer with the seam allowances sewn together inside the space between the inner and outer pack bottoms.  To do this, the rear side of the pack bottoms must be left unsewn until last, and the bottom layers later top stitched to the back panel of the pack. The top stitched seam on the bottom can include whatever you want to use to connect the pack to a frame, or other stiffening device.  Am working on one now, and will post with attention to bottom seams when finished.

I’m putting in a vertical inner divider, so the bottom of it will be inside the pack bottom’s perimeter, therefore it’ll be exposed to the ground (when standing up).

Does the vertical divider have to be sewn on the bottom? Can it just be sewn in the front and rear panel of the pack body?

Here’s another option … look at the Kelty Model A below. If you can do something like this, I can take detailed pictures of the construction

Nick: https://backpackinglight.com/forums/topic/how-to-protect-stitching-on-bottom-of-pack/#post-3638160

“I’ve thought about leaving the bottom loose. I’d rather not—I want to be able to put small items in one compartment with confidence that they won’t migrate to another.”

put small items in one compartment
My external frame pack has only one compartment, by choice. I solved the small items problem by putting them all in one multi-coloured silnylon stuff sack and keeping that near the top. Works fine.

Cheers

Extra rows of stitches and sealant over them on the outside. By the time that wears out, you will have figured out things you want in a new pack project anyway

I find the best way to protect the stitching on the bottom of the pack is to not have any exposed. I make the bag itself, with stitching everywhere, then I make a cup-shaped outer cover of stronger material with bread-tin folds up the sides which is sewn to the full bag around the top perimeter. That also protects the weaker bag fabric from being dragged over rocks etc. Made many packs that way.

Cheers

Roger—That’s a clever solution. I’ve seen it used on separate bathtub floors to use with tarps, but not on packs.

“… then I make a cup-shaped outer cover of stronger material with bread-tin folds up the sides which is sewn to the full bag around the top perimeter. ”

Agree, a super solution.  Avoid all the manipulations of the pack inside out, and outside in, while sewing.