18l & 24l FastPacks – lessons learned from 30+ packs so far @montmolar

[Montmolar]

Hey folks,

since I’ve been pretty known for my FastPack design(s) I want to use this thread to share my learnings and the current state of my design philosophy with you.

The Montmolar 18-24l FastPack (9.4oz / 266g) – An In Depth Look

The FastPack Origin

My MYOG journey basically started with my wish to modify the existing Aonijie 18l trail running vest (±325g) to better fit my needs and especially use lighter and more advanced fabrics to do so. And as we all know: One thing leads to another and the perfect pack is always n+1.

So since then I have continually evolved the design over the last two years and reached a point where I supposedly have “seen” it all. Which just means: I literally have experimented with so many fabrics, components, tapes and cords, that I pretty much bought every feasible item from any commercial store all over the globe.

I found many gems and so this thread aims to distill the experience into a usable blueprint for each and everyone aiming to make their own Montmolar style FastPack – or any similar pack for that matter!

What you need (and don’t)

After much trial and error I can share my findings in terms of fabrics and components as part of the bag:

1) Main pack Fabrics:

• 40D TPU Nylon (70g/m² or 2oz/yd²) – $ cheap, easy and still quite robust/waterproof. Can be seamsealed / welded. There are more potent fabrics for the weight though.
• XPac LiteSkin LS07 (115g/m² or 3.4oz/yd²) – $, really nice fabric for its weight, seems durable, great feel and texture. Fully waterproof but hard to seamseal. Maybe problems with delamination on areas of continous folding? (No personal experience so far.)
• CT5K.18/blkwov4 Hybrid DCF (102g/m² or 3oz/yd²) – $$, nice to work with, fully waterproof, pretty robust, easy to seam tape, quite sturdy, the face fabric will help only so far with abrasion… (seen some wear on my personal EDC wallet).
• X-Pac X21 RC (150g/m² or 4.4oz/yd²) – $, rather stiff and burly, holds stitches well, fully waterproof, can be seamsealed, I don’t miss the inner fabric vs. VX21, problems with abrasion on x-pattern?
• CT5K.18 1.43oz DCF (48g/m² or 1.43oz/yd²) – $$, lightest pure DCF I would recommend for packs, seems really robust and sturdy!, holds stitches well and is easy to work with + seam tape. Fully waterproof.
• Dyneema Gridstop TPU Laminate (130g/m² or 3.9oz/yd²) – $, quite soft, seems pretty tough, moderately waterproof, could probably be seamsealed
• PU1000/DWR Woven Melange Dyneema (237g/m² or 7oz/yd²) – $$$, interesting fabric, strong and totally abrasion resistant, quite soft and mellow, not as waterproof as other fabrics, difficult/impossible to seamseal.
• Venom UHMWPE TPU coated (132g/m² or 3.9oz/yd²) – $$$, feels extremely robust and quite sturdy, highly waterproof, can be seamsealed, some minor imperfections from production are normal, TPU coating is prone to failure over time…
• Ripstop Polyester 300D (aka HyperD) – (135g/m² or 4oz/yd²) – $, quite soft and mellow, not as waterproof as other fabrics, difficult to seamseal, PU coating might wear off. Good for prototyping because of easy handling.
• Ecopak Ultra EPL 200 – (119g/m² or 3.5oz/yd²) – $$$, THE current backpack fabric, incredible strong for its weight, easy to seam tape and to handle.
• Ecopak EPLX 200 – (146g/m² or 4.3oz/yd²) – $, similar to XPac RC but slightly lighter and easier to seam tape, also not as stiff but more smoothly. Choose over XPac.
• XPac UVX40 – (241g/m² or 7.1oz/yd²) – $$$, interesting fabric, strong and totally abrasion resistant, hard to work with because of stiffness, difficult to seamseal. Might be better suited for haul bags.
• Ecopak Ultra EPL 100 – (99g/m² or 2.92oz/yd²) – $$$, the lightest Ultra fabric, incredible strong for its weight, easy to seam tape and to handle. My absolute favorite right now.

TLDR: Ultra 100, Ultra 200 and LS07 are my current favorites. I am looking forward to trying a yet to be released even lighter Ecopak DTRS75 fabric though.

I would rather advise against these fabrics:

• 20D SilNylon (36g/m² or 1.1oz/yd²) – $, a pain to work with, not very waterproof and stitches won’t hold properly… Stay away.
• CT2K.18 1oz DCF (34g/m² or 1oz/yd²) – $$, not as robust, easy to seam tape, ultralight and feels a bit too delicate. Fully waterproof. Rather use a bit heavier DCF (see below).
• 70D TPU Nylon – (170g/m² or 5oz/yd²) – $, not as good as the 40D version, tears rather easily, can be seamsealed / welded. Stay away.
• Cordura + Vectran Ripstop – (410g/m² or 12.1oz/yd² ; 360g/m² or 10.62 oz/yd²) – $, way too heavy, hard to cut and really robust, difficult/impossible to seamseal, not as waterproof.
• Technora X-Ply Laminate – (100g/m² or 2.92oz/yd²) – $, clear & waterproof, doesn’t hold stitches well, hard to seamseal. Stay away.

2) Vest Straps / Harness fabrics

• 3D HexMesh (405g/m² or 11.86oz/yd²) – $, heavy, rather stiff, great comfort and handling.
• 20D Monolite / Monofil RipStop (34g/m² or 1oz/yd²) – $, lightest option I sufficiently used, does need a high level of care and might still fail (ripping at the seamholes).
• 3mm 3D Spacer Mesh (300g/m² or 8.85oz/yd²) – $, reasonably robust and strong, good comfort and handling, not as breathable as the other ones.
• AliExpress HexMesh (±224g/m² or 6.61 oz/yd²) – $, not as strong as the other HexMesh, but way lighter, pretty stretchy (take care with warp&weft!)
• AliExpress Triangle Mesh (±153g/m² or 4.51 oz/yd²) – ($ – not for generic resale), lighter than the Ali HexMesh, but imo more robust and less stretchy! My personal favorite.

Might try some Coolmax Polyester some time, as another lightweight option (120g/m² or 3.54oz/yd²).

3) Stretch / Pocket fabrics

• Nylon Light Lycra (80g/m² or 2.36o/yd²) – $$, lightest stretch fabric I found viable, still prone to snagging if mistreated, really stretchy!
• Nylon Sports Lycra (190g/m² or 5.6oz/yd²) – $, really stretchy and rather robust, pretty heavy though.
• Strong Stretch Mesh / Powernet (160g/m² or 4.72oz/yd²) – $$, really robust and still stretchy, more “seethrough” than Lycra. My fabric of choice for all external pockets!
• Powermesh Bi-Elast. (110g/m² or 3.24oz/yd²) – $, really stretchy, feels a bit flimsy, still decently robust, may wear out with hard use. Only use for inner pockets.
• Spandex / Poly Blend (AX Stretch Mesh) (180g/m² or 5.31oz/yd²) – $, moderately stretchy and robust, rather heavy.
• Dyneema Nylon Ripstop Elast. (230g/m² or 6.78 oz/yd²) – $$$, extremely robust, only low stretch, perfect for the bottom pocket!
• Venom UL Stretch UHMWPE Mesh (169.5g/m² or 5.0 oz/yd²) – $$$, extremely robust, only low stretch (comparable to Dyneema Mesh, lighter and thinner than Dyneema mesh, perfect for the bottom pocket!

For this part I’ll only mention what has proven to be the best choice imo – mentioning everything I tried would take waaaay too long. :)

4) Hardware (Buckles, Cord Locks …)

• 2x Woojin Plastic 10mm Dual Adjust Buckle (Roll Top Closure)
• 2x WP Sternum Clip Buckle
• 2x WP 10mm Sternum Clip
• 1x WP 10mm Adjustable Webbing Hook (top strap)
• 1x Double Cord Lock (front elastic)
• 2x Ultralight Springless Cord Lock (side compressions) – working on sourcing / printing a more minimalist part (as used on TNF jackets)…
• 2x WP Pulling Cord Lock (better than Cyberian Cord Lock! – for lateral adjustments)
• 3x 25mm Slik Clip (top connection)
• 10x Mini Cord Guides (side connection) – could be supplemented with D-Rings, Beastee D-Rings or just plain 10mm webbing
• 1x WP Micro Whistle

5) Webbing, Cords and Elastic

• 10mm Thin Webbing (most adjustable straps incl. sternum straps)
• 12mm Thin Webbing (ice axe loop, haul loop)
• 10mm & 15mm Elastic Webbing (pockets + elastic portion of sternum straps)
• 10mm Reflective Webbing (front stretch pocket)
• 25mm / 1″ Venom UHMWPE Ultralight Webbing (top connections) – could use regular 25mm webbing as well.
• 1.3mm Dyneema Cord With Polyester Cover (lateral connections + small loops)
• 2mm Elastic Cord (pad suspension on the back, elastic on the front, bottle retention, side compression)
• 21mm Thin Edge Binding Elastic (vest harness binding)
• 2.5C (4mm flat) Zipper – 20cm (lower pockets on vest harness)

5.1) Options for finishing the Roll Top (ordered from most-> least prefered)

• Velcro Omnitape (Hook & Loop in one strip)
• 6x Neodymium Magnets 30x10x1mm
• 2-3x Micro KAM Snaps T3
• Polyethene Tape 20x1mm
• 20mm Webbing
• Snap Line
• YKK or HHH or AX zipper

6) Tools, Needles and Thread

• Saxony Tape for seam taping (more flexible and better adhesive vs. DCF tape!)
• Shrink Tubing for finishing zipper pulleys and cords
• Schmetz MicroTex 5×70 (not for ultra burly fabric, but leaves the smallest holes i.e. less damage)
• Nylbond 80 thread (really strong, yet thin thread)
• Prym Trick Pen for marking (self erasing) or Ultimate Marking Pencil (kinda like chalk)
• basic seam ripper, lighter, mini roll cutter, scissors, (big) cutting mat and (big) fabric ruler
• (KamSnap Tool)
• (Laser for cutting)

[Pierre Descoteaux]

Great info! Thank you for taking the time to share your thoughts on so many different products for myog.

[Sam Farrington]

Agree about the Ecopak Ultra from the evidence, but haven’t tried it yet, so thank you for confirming its high standing.  The price is not punishing when only need enough for a pack.

[Tyler R]

This isn’t really on topic with this thread… And I haven’t attempted a MYOG pack so take this all with a grain of salt… but I’d like to add some thoughts that support, and add to, the generally perceived merits Montmolar has gained from the community to emphasize how awesome and useful this post is to anyone looking to do a MYOG pack.

Being one of the lucky few with a Montmolar fastpack (a newer one at that too), I can independently attest to just how well thought out every aspect of the pack is. Everything from the hardware choices, chosen methods of adjusting fit (one handed too!), and overall layout is top notch. So I do not doubt in the slightest that all these little secret treasures, observations, and lessons he is sharing here are of very high value to anyone who partakes in MYOG.

It’s not just that they are well thought out and backed up by brilliant ideas/design… I’ve been told I have good ideas and the things I make perform as I generally describe them too, but they still look rather janky like the kitchen counter top MYOG items they are… However, with Montmolar, IT’S THE CRAFTSMANSHIP TOO! Montmolar has some serious skills and it shows. I haven’t had as many packs as some (4 frameless, 3 framed), so I may not know entirely what I’m talking about… But anecdotally, none of them have been this well taped, sewn, and exhibit this level of overall skill/detail in the construction alone. Everything about this pack is a piece of art from an exceptionally skilled and talented craftsman and you notice it from the second you see it in person for the first time.

I know this because I experienced it personally and on my last hike I was stopped twice and asked about my pack… I have never been stopped to be asked about my pack before.

As far as durability, I honestly can’t say. My intuition is that it will hold up just as well as my other frameless UL packs; But I haven’t had many trail miles with my pack yet to be certain. From the initial 80 miles I have put on it so far though, I can say this is the most comfortable pack I’ve tried yet(very impressive for a frameless IMO). But I know that based on Montmolars lighterpack profile, I’m loading my pack with about 2.6 more pounds than Montmolar does and I’m personally known for being rather fast and aggressive on the downhills in ways only the young and dumb can manage. So all that dynamic loading over time should be a great test for his unique vest strap attachment method. Which I honestly think it’ll hold up just fine, but I bring it up because it always seems to be one of the design decisions people ask about the most when they see pictures/videos of his packs.

Anyways, apologies for the off topic praising from someone who doesn’t even do MYOG packs.

[Paul S]

Thanks so much for sharing. Your pack looks awesome!

 

[Author]

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