3D mesh questions

[Justin T]

Hey y’all, long time lurker, new member, first time posting. After searching this forum and others for a couple months I’ve decided to take on a backpack. This is I’m sure the first of many questions that I’ll have but as I am trying to tackle the shoulder straps and hipbelt first, I’ll start there. I’ve traced my pattern out on my hyperD 300 and my 1/4 inch spacer mesh, right sides together with some extra fabric for wiggle room. I got them sewed together without much issue, however when I flip the strap inside out the mesh and fabric seem to now be warped creating a big gap where the mesh is like half moon shaped and leaving me scratching my head. Any ideas on the cause or fix of this? I plan to stuff them with 3/8 inch foam will that balance it out? Thanks!

[R]

Do you mean the mesh is bowed, as if you sliced a drinking straw in half the long way?  Is everything ok if you squash it flat with your hand?

I haven’t worked w/ that material, but I have some and based on the squishy, springy nature of it, I wouldn’t be surprised if it bowed like that.

Stick some foam in and see!

[Sam C]

Don’t worry, this is what it does.  When you slide the padding in it will flatten out and look “normal”.  This also happens with non-3D mesh fabrics, too.  Think about what is happen here;  you essentially had sewn two pieces of fabric together, flat, and in their “desired” orientation.  Then, you flipped it inside out, if you will, causing the fabric pieces to fold/bend back onto themselves disrupting their natural states of lying flat.  The curling effect is caused from the tension of the fabric wanting to flatten back out.

Also, don’t be surprised when/if you find the that the straps had shrunk.  You need to include the height of padding into each piece otherwise your width will be short by that much.  For example, if you want 3″ wide straps and are using 1/4″ foam and 1/4″ allowances and only cut your pieces to 3 1/2″, you will end up with  with 2 1/2″ straps or so, to give an example.

 

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