Breathable foam for pack straps

[Colin Krusor]

I'm working on a pack and trying to decide on a design for the shoulder straps. I like thin, breathable mesh straps like those on the Nathan vest-packs when the load is very light, but with overnight loads I find myself wishing for straps with padding.

Reticulated foam came to mind as a way to make shoulder straps that are both padded and breathable. I would sandwich it between layers of soft mesh fabric. It is essentially a three-dimensional screen.

I ordered some and it arrived today. The product I found is called Poret and I got mine from an aquarium supply company. t has ten pores per linear inch and it is extremely breathable. I can blow through it with basically no resistance. It also appears to be very bouncy and resistant to compression set. Has anyone used this kind of foam? Does it have any shortcomings that I haven't forseen?

[Dustin Short]

I'm very intrigued by this, looks like a great way to add a lot of softness to straps without much weight.

How much does it weigh/volume?

The only concern I would have is it's durability. With a lot of sheer stresses during compression, the strands may tear and eventually flatten out. This may be minimized by some clever sewing/design of the straps but not sure where to start.

Either way, keep us updated on how well it holds up and performs!

[Jerry Adams]

They make scrubbing pads out of a similar material

I would be interested to find out how long it lasts before flattening

I've put it in the shoulders of a rain jacket before. I'll get sweaty on my shoulders, upper back, and head before anywhere else so a spacer like that might help.

You could also put it on your pack where it presses against your back.

Yeah, report back your esperiences.

[Daryl and Daryl]

Colin,

Nice find. I like the looks of this stuff.

Daryl

[Terry Trimble]

Good find I hit up local aquarium distributor but they did not have sheets.

Some of the older heavier packs used this foam in sandwich form. For example Mesh or 3d foam,the type foam of foam you found and closed or open cell foam to make it breathable and transport sweat away in to the air. Now most of the manufactures use perforated die cut foam that we cant afford to manufactuer.

The only way we can make perforated closed cell foam is with a hole punch and a hammer and punch holes in 1/4 inch foam.

I have Jandd Mogen 35 liter panel loader that uses this type of foam and mesh on the back it works in wicking transporting moisture really good.
Terry

[Paul McLaughlin]

I have used this stuff in the past – I have a pack with a hipbelt that has a layer of 3/8" Blue-foam and a layer of reticulated that is over 25 years old and has been used on many trips. The reticulated has compressed some, but I would say less than 50%. As to the breathability, I think you'll find that overrated. By the time you cover it with fabric of some kind (I used Leno mesh for maximum breathability) you'll end up sweating about as much as you would with most hipbelts – at least that's my experience. I have not used it since on any of my packs. I suspec tthe main issue is that it is very breathable when not under compression, and less so when compressed – and it compresses quite easily. That belt is still very comfortable, however!
My current solution is to use breathable fabric (uncoated 160d cordura) and perforated 1/4" thick closed -cell foam. Not perfect but I'm pretty happy with that.
I also tried some Brock Foam – supposedly breathable foam that many pack manufacturers were using – but found that it doesn't hold up well.

[Nick Gatel]

Is a breathable shoulder strap that important? Sweat under straps has never been an issue for me. For a really light pack, I like what GG does on their Murmur pack. The edge of each strap is velcro. You can take out the stock foam and replace it with bubble wrap or even socks. Bubble wrap is pretty darn light. Or you could use the Poret? This way if your padding compresses, it will be easy to replace.

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