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replacement for foam support in daypack?

Posted: January 10th, 2021, 8:41 pm
by Mukluk
I have an REI daypack that quickly ends up folded in half in an awkward position if there are only a few things in it.

It has a sheet foam pad insert against my back, but that's not stiff enough to keep from folding. I'm thinking of gluing some vertical thin wood or plastic strips to the foam to stiffen it up.

Any better recommendations for how to keep the pack's shape? Or a replacement material for the pad?

Thanks!

Re: replacement for foam support in daypack?

Posted: January 11th, 2021, 10:03 am
by Webfoot
I think expanded polypropylene (EPP) sheet would work mechanically if you can fit a thick enough piece. It would probably also be sweaty so I would plan on holes for breathability but they would need to be thoughtfully applied to avoid compromising the stiffness of the sheet.

Re: replacement for foam support in daypack?

Posted: January 12th, 2021, 8:53 am
by Chip Down
As I understand it, the foam sheet resides in a pocket inside the pack, and can be removed (or if it can't be removed, at least the pocket is open at the top so additional layers can be added).

Rather than adding strips, I would add a full sheet. But if you're generally happy with the pack's structure, other than the annoying folding, then I suppose adding some ribs would help. For a daypack, I wouldn't want it to be completely rigid. That's just me though; some manufacturers do, or used to, use aluminum bars, generally one on each side (left and right).

I wish packs were more versatile. I'd like to see more packs featuring removable back support, so users can easily customize to suit their needs.

Re: replacement for foam support in daypack?

Posted: January 12th, 2021, 6:35 pm
by Mukluk
Webfoot wrote:
January 11th, 2021, 10:03 am
I think expanded polypropylene (EPP) sheet would work mechanically if you can fit a thick enough piece. It would probably also be sweaty so I would plan on holes for breathability but they would need to be thoughtfully applied to avoid compromising the stiffness of the sheet.
I don't see any cheap options for EPP online, just big sheets for $40 and up. Know of any local sources?

Re: replacement for foam support in daypack?

Posted: January 13th, 2021, 10:41 am
by Webfoot
RC hobby shops may have smaller pieces. I think the #1.9 (pound per cubic foot) density may be enough but denser would probably be better; handle it first to check stiffness if possible.

https://windcatcherrc.com/product/9mm-t ... p-36-x-24/

Re: replacement for foam support in daypack?

Posted: January 14th, 2021, 6:33 pm
by aiwetir
Seen them at the fabric store too, not sure of the price, but I did take note for future foam carving projects

Re: replacement for foam support in daypack?

Posted: January 28th, 2021, 4:13 am
by Kay Burton
Isn't it easier to get a smaller backpack for those situations when you don't need to put a lot of things in your backpack? After all, it will be more convenient than carrying a healthy backpack, in which several things dangle on the go.

Re: replacement for foam support in daypack?

Posted: January 31st, 2021, 3:00 pm
by Mukluk
It's a pretty small pack.

I got a hydration bladder and it gives the pack enough structure to keep it's shape, at least until it's almost empty.