I'm trying to make a hipbelt similar to the hipbelt on the ULA Circuit, which appears to consist of two densities of foam--one, a broad, thin and relatively rigid foam that gives the belt its structure (this foam is on the "pack" side of the hipbelt); and two, a thicker softer foam that is wrapped in 3-D mesh (this foam is on the "hip" side of the hipbelt.

Overall, this combination of rigidity and softness combines to make an excellent belt for both comfort and weight transfer.

I'm trying to source the thinner, stiffer, more rigid foam. Does anyone know where this type of foam can be purchased? Is the GG thin light pad relatively rigid?

Thanks all

Is the GG thin light pad relatively rigid?

Nope, it is definitely not. Haven't seen a ULA Circuit so I can't say what might be similar.

Thanks, Jim

After I went hunting for this type of foam and failed I was told that a good place to try would be some packaging firm. They use high-density stiff foam for packing things and often have off-cuts.

Alterantively....

I've done a load-bearing belt. I made a laminate as follows:

The outer belt fabric was 200d Cordura. The inner fabric was 3-polyester mesh. This was made into two pockets.

For the load-bearing I used some camping mat foam as 'soft foam' - which doesn't carry load.

I then went to a cheap stationary store and bought some clip binders that had thinish flexible plastic covers - I tested them in the store ;-)

The plastic was sliced and bonded to the foam using carpet glue.

The foam and plastic was then slipped into the two pockets and the pockets sealed.

The plastic distrubutes the load.

The foam mid-layer moulds to the hips,

The 3d mesh helps to wick moisture.

For a perfect fit I also used two 1" buckles spaced at 1". This means that I can tension them differently to determine exactly how load is carried.

This is all basically a copy of what the military issue in some countries.

Edited by ArchNemesis on 02/29/2008 16:13:56 MST.

Good suggestion. I've been thinking about using some plastic and this strategy may work.

At Wal-Mart, they sell a 3-pack of thin, flexible cutting boards for under 4 USD in kitchenware. That material takes a lot of abuse.

While you are at Wal Mart buy one of their blue foam sleeping pads along with the cutting board plastic stuff.

I have used the blue foam pad with the cutting board stuff on the back for a hipbelt.

I have some pictures of my last pack / frame and the hip belt for it was made that way. Look in the MYOG forum for the thread.

I did look at cutting boards. They are quite heavy.

Remember, in a hip belt the plastic the plastic is being bent inside an envelope perpendicular to the plane of the plastic and the load is applied parallel to the plane of the plastic - so provided that the plastic cannot flex sideways it will carry a tremendous load.

As a test I strung 20lbs of weights from the belt and it handled it beautifully.

The plastic that I picked up was 0.5-1mm thick and would easily flex for less than the diameter of my hips.

It does make a big difference to load-carrying and you can easily see how your hips are torqued by applying load in the normal positions.

I hope to write some of this stuff up RSN...

Edited by ArchNemesis on 03/01/2008 05:31:09 MST.

The flimsy, flexible cutting boards are ~.5mm thick.

I found this at seattlefabrics.com:

200 Denier Oxford Foam Laminate
200 Denier Oxford that is laminated to 1/4" open cell foam and backed with a fine tricot mesh. This makes a quick easy project where you want to add some padding. Black Only.

60" $16.50/yd


This is basically ready made stuff what Mike described above. My question is will 1/4" foam be good enough for hipbelt and shoulder straps carrying 35-40lbs?

The Aarn bodypacks have a hip belt of thin stiff foam and fabric from the pack, round your hips to the hip crests then an "S" or swan necked seam to a flexible 3D mesh front part of the belt. The middle part of the swan neck mimics the shape of your hip crest. A double anchored adjustable belt buckle pulls high and low on both "wings" of the belt and this causes the mesh to wrap round your hip crests very comfortably and carry the load very well, much better than unshaped thick padding. Aarn's big idea is carrying maybe 1/3 of the load in front pockets, these stand off the front of the hip belt and balance the load coming from the main pack at the back . You should be able to carry 35 lb with no backward pull on your shoulders.
He has large velcro squares to adjust each belt "wing" so as to get the belt exactly fitting different people.

Thanks for the info on Aarnpacks. I check their website. Innovative but I am not sure I would be comfortable with two big pockets on my chest.

After bit of research I am not sure if open foam would be a good choice for padding. I think EVA or XPE would be a better choice.

glue a sheet of cuben using goop to a 4 in belt of a 3/8 in sleeping pad, it won't stretch and the padding is inside! use appropriate hardware.

the 1/4" open cell foam is to make the mesh 3d. It isn't intended to be the main padding. It is best to pair it with 3/8" or 1/2" foam. I have 1yd of the oxford/foam/mesh you are talking about on order to see how it compares to comercial 3d mesh. I will post how it is. If it is the good stuff i will make sure my post is after my next order (j/k)

-Tim

Osprey has termo moldable hip belt. They call it the IsoForm. Some of their certified dealers have ovens to heat and mold the hip belt to you in the store at the time of purchase. This way the average Joe can't screw it up.

***sorry if you're name is Joe, nothing personal. I'm must have just stepped on some Joe's shoes out there.

I would like to know what kind of thermo foam Osprey is using.

Edited by matthewjamesroberts on 03/25/2009 22:05:05 MDT.