Tips/Validation Needed for first MYOG Pack

[Hoosier T]

Hey folks, as you might have seen, I’ve done a lot of MYOG, just not yet a pack. I’m building something similar to an HMG 2400 (ruck sack with roll top; waterproof) to compliment my quickstep for the longer trips. Here is what I have so far:

X-PAC X21 RC for entire body.

Lycra Mesh for front pocket. It will be tall, like an OHM.

Tall side pockets made from HyperD300 for storage. These will be about twice as tall as standard bottle pockets with no cant. I carry my water bottles on my shoulder straps and a Platy bag in my pack.

Need some advice on shoulder straps and hipbelt:

1. Is Hex70 breathable strong enough for the front of the straps and hipbelt? I want something breathable and don’t feel it needs to be bomber.
2. 1/4 FY20 foam with 1/4 3D spacer mesh ….OR 3/8 foam with 1/8 3D spacer mesh?

I plan to use Tera 60 with a size 16 schmetz jeans needle. Is that a sound decision? Never used anything this heavy but also never made a pack.

I will also be using 1/8″ thick x 1/2″ wide 7075 aluminum stays that I will bend accordingly.

Thanks in advance for you input.

[Hoosier T]

Missed a couple of details. I will use a winged hipbelt with a fairly narrow gap (~4″) between their connections. The backpanel with have two sections of Power Mesh (like GG) to hold a sitpad. Per my other thread, the stay sleeves will be nylon webbing sewn to a large piece of 1.43 cuben. This will be the exact same size of the actual back panel and the entire piece of cuben will be taped to the inside of the X-Pac backpanel. This will eliminate any holes being sewn into the backpanel and improve waterproofness.

[AG]

unrelated question.. but can you share how you are taping the seams?

[Hoosier T]

I taped the seams in my quickstep carefully with cuben tape. I will do the same with this pack. I made my own cuben tape with 3M 9485PC and cuben. For this pack I would make the tape with the heaver 1.43 cuben for some added strength at the seams. It’s a minuscule weight gain to do so. Were you looking for more specifics?

[Hoosier T]

I would still appreciate some input on this:

Need some advice on shoulder straps and hipbelt:

1. Is Hex70 breathable strong enough for the front of the straps and hipbelt? I want something breathable and don’t feel it needs to be bomber.
2. 1/4 FY20 foam with 1/4 3D spacer mesh ….OR 3/8 foam with 1/8 3D spacer mesh?

I plan to use Tera 60 with a size 16 schmetz jeans needle. Is that a sound decision? Never used anything this heavy but also never made a pack.

[David Chenault]

I reckon Hex70 will be more than strong enough, the only questions I’d have (having never seen it myself) would be how much it stretches.  If nothing else avoid orienting the bias in the direction of load.   Unless you preferate the heck out of your foam I don’t think having breathable fabric on the harness elements will do anything for you.

I’d vote 3/8″ foam.  1/4″ FY20 is great with a 1/16″ layer of 20 pound as a backer to spread out of the load, but I don’t like it alone for anything beyond a 20 liter daypack.  Too much tendency to roll and deform.

Tera 60 will be fine.  I like a finer thread and needles, smaller stitch length, and double stitching over the opposite.  In my experience that will give you better resistance to stitch hole enlargement and the like.  X21RC doesn’t have especially impressive tear strength anyway, and single stitched seam in it with decent thread like Tera 60 will rip by hand stitch hole to stitch before the thread is troubled.

Good overall plan with the suspension, those stays will do you very well.

 

[Eric Blanche]

I recently made a pack with hyperd300 and hex70. I used the pu coated hex70 and i do think that is absolutely strong enough based on hand feel and working with the material. I do not know actual specs though. I used 3mm (1/8) 3d mesh with 3/8 foam for the shoulder straps using the inside out method. I think the 3/8 foam is a bit overkill for the weight my pack would carry (under 20 at all times). The Ohm/ula shoulder straps are far thinner and I would say are just as comfortable. With that said, I think the 1/4 in and 1/4 in would offer a softer and perhaps more cushy feel compared to going with thicker foam.

Have you considered ordering samples from ripstopbytheroll? They do a sample of four swatches for real cheap. Great for selecting color and/or fabric choice.

I agree with David when it comes to the needle/thread choice.

Good ideas for the stays! I look forward to seeing this pack with the stretch mesh front pocket. Good luck and make sure to take a lot of pictures!

[Hoosier T]

Thanks guys. I’ve done samples from them and worked with most of their materials but never had a need for hex70 until now. I will take your advice on the needle and thread as the thicker needles are definitely hard on my machine. I’ll grab some Tera80 for it but do you guys use sharp or jeans needles? I’ve only ever used schmetz sharps but have read a lot about jeans needles for packs.

[Sam C]

 

1. Is Hex70 breathable strong enough for the front of the straps and hipbelt? I want something breathable and don’t feel it needs to be bomber.

I use Hex70 extensively;  love it, it’s likely my favorite fabric.  The “breathable” is the DWR without the PU coating, which I’ll reference simply as DWR.  I have used this version of Hex70 for both hip belts and shoulder straps and you’ll have no problem, either.  The PU coated Hex70 is a little more abrasion resistant, though.   Because the DWR Hex70 is not PU coated, it is prone to unraveling at raw edges.

Anyways, yes; the DWR Hex70 will be strong enough.

As an aside, if you are a gram counter and don’t care for the PU coating, you might want to also look into the 1.7 oz. Robic XL hybrid fabric also at RSBTR.

1. 1/4 FY20 foam with 1/4 3D spacer mesh ….OR 3/8 foam with 1/8 3D spacer mesh?

3/8″ foam with 1/8″ 3D mesh is the typical combo used by most MYOGers. Likely because those blue foam pads you see in the sporting goods section are 3/8″, and, 1/8″ 3D mesh is both cheaper and lighter than 1/4″ 3D mesh.

I’ve used 1/4″ foam in the past, and find that it has a property that I like that 3/8″ does not have;  it’s more flexible/bendy whereas the 3/8″ is stiffer.

Aside #2:  In the past I had used a textured fabric for the undersides of shoulder straps and hip belts because textured fabrics are grippy by nature, then I had moved on to 3D mesh because it seemed all the rage.  To be frank, I find 3D mesh difficult to work with and have moved back to using textured fabrics.  For one, sewing through a completed strap, with 3D mesh on the underside, seriously throws off my tension and I bird nest almost every time no matter what “trick” I employ to combat.  Yet with with any other fabric this does not happen (well, not nearly as often, anyways).  And, two;  3D mesh has a tendency to stretch forward as you sew.  A lot of mesh fabrics do this, but imagine if you had cut two pieces of fabric, one a 3D mesh and the other, say, X21, both of the same width and length, and had aligned raw edges and had then sewed down the length of one side; you’d find that the 3D mesh is now 1/2″ or more longer than the X21.

As for the thread:  most MYOGers seem to believe that you match the needle to the fabric, but in reality you should match the thread to fabric then the needle to the thread.  Of course this means that the needle is then matched to the fabric but if you skip the thread part then you may end up using the wrong thread for either or both the needle and/or fabric.  If you can thread the needle the needle will punch through the fabric, but if it’s the wrong thread for the fabric then the bottom stitch may not properly lock with the top stitch (aka, throwing off the tension).  Good news, you can adjust the tension on your sewing machine to correct this.  The bad news is that once you start fiddling with the tension controls it might be difficult to get it back to the factory setting, which is the “sew all” setting.

 

[Hoosier T]

@davec

I was considering a harder 1/8″ foam sandwiched with 1/4″ fy20 (2lb) for the hip belt. How do you think that would do for shoulder straps?

[Hoosier T]

Alright, so I pulled the trigger on all materials. Here is the breakdown:

Pack body – X21 RC Gray/Black two tone

Pack bottom – X51 Black

Front Pocket – Gossamer Gear front pocket mesh from current gen packs

Pad holder – 4-way power mesh (copying the pad holder from GG packs as I love it)

Side Pockets – Hex70 PU3000

Hipbelt – Hex70 PU3000/1/4″ FY20 foam/1/8″ 12lb EVA/1/8″ spacer mesh

Shoulder straps – Hex70 PU3000/1/4″ FY20 foam/1/4″ spacer mesh

Stays – 1/2″ W x 1/8″ thick 7075 aluminum flat bars bent to shape. The channels will be sewn on the outside of the pack running down the back panel behind the sit pad. The hipbelt wings will be 5″ apart (with a lumbar pad between) and the stays will slide down into the back of the hipbelt 1/2″ out from where they are attached to the pack. This leaves me with a gap of 6″ between the stays.

[Hoosier T]

Need a little help. Never had one problem sewing anything thus far. But I’m currently sewing the daisy chains on the hipbelt and my machine will not zigzag (bartack) through it. The bottom thread won’t catch. Either way, I have to hand crank it and straight stitches are going fine. Any tips for getting the zigzag to work or do you thin back and forth straight stitching is okay? Have adjusted top tension to no avail. Have not touched bobbin tension.

Details:

Tera60 thread

Tried both 90/14 Sharp and Leather needles

Layers are: Hex70_+ 1/8″ 12lb EVA foam + 1/4″ FY20 foam + 1/8″ spacer mesh

[R]

My next step would be the bottom tension.  If you’re mindful of how far you turn it in which direction (no less than 45d – but I’d probably start w/ 180d increments) you should be able to restore it to it’s present setting.

You might try a touch of lube on the needle.

Will the daisy chain be heavily loaded?  Does it need to support the full tension of the belt?  Several passes of straight stitches should be fine, especially if you’re sewing in several places.

Some other possible work arounds:

• Don’t sew through the full stack.  Maybe just go through the Hex70 and add a backing layer of Hex70 that will be hidden inside the belt, or a backing layer that spans the full height of the belt so it gets included in the edge seams.
• Cut a hole out of one of the foam layers where you need to sew through it, so you have one less layer to go through.  Maybe experiment on scraps to see if there’s a viable stack of layers that you can sew through.

[Author]

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