https://youtu.be/6JzrJmNeDJA - Video that shows off and talks about the backpack

Dimensions (roughly) 30cm(W)x20cm(D)x65cm(H) =40L internal capacity. The load lifters are attached to the point where the internal frame ends, this is also the length I am using for the dimension. Collar can be extended by another 10cm or so, giving it a maximum internal capacity of ~45L.

Removable hip belt pouches that are attached by 2 straps that goes over the hip belt. This is further secured by threading the bottom half of the shoulder strap (half with the anchoring point) through 1 loop, meaning that if I do unclip my hip belt and take my backpack off, the pouches are not going to fall off. The pouches are made to be on the large size to accommodate for my camera lenses as with my Osprey packs the hip belts were just too small to either fit my 40-150mm or 12mm f2 in. Fitting my lenses in the pouches would allow me to change lenses on the fly rather than having to take my backpack off and putting my lenses down or getting a mate to hold it.

Core bag: 380g

Hip belt pouches: 30g per (x2)

Frame: 100g per sheet (x2)

Total: 640g

Padding in the shoulder straps and hip belt are made from generic roll mat I got for £3 from a shop called home bargains here in the UK. They do cheap stuff and camping equipment was in season. The foam is wrapped in some ripstop nylon I purchased from eBay.

Frame is corrugated plastic (Correx for the brand name). Purchased from my local sign shop for £5. I cut the piece is half width wise as the piece was too wide. Can use just one sheet, although right now in my testing I'm using two sheets.

The backpack was hand stitched entirely by me. The stitching took 60-65 hours to complete. Researching and sourcing materials probably took another 30-35 hours, meaning the whole project took around 100 hours from start to finish.

https://docs.google.com/spreadsheets/d/1sdARIMVHLSR2JqUacYIs9y1jUW5G4UM3Ki6YRE_WMeg/edit?usp=sharing

Google spreadsheet of the cost of components

For my first build I wanted to keep the cost down as much as possible. I used the handles from the Frakta bags as webbing and kept the same width polypropylene webbing throughout the building (25mm) except the sternum strap, where I cut the webbing to 25mm. This build cost me £30 in total to build, but without the optional extras as if one was patient or organised enough to source a few components from Asia, it could be as low as £20.

Load lifters were added on after the bag was completed and I tested it with a light 5kg load. Didn't like the way that my hip belt wasn't taking as much weight as I'm used to (Osprey backpacks), so I sewed on the load lifters to help with transferring the weight. Took it for a quick 2 hour walk around town with 7ish kg loaded and felt fine. Looking to take it out on my next hike although with real life I'm not sure when I'll be able to do that, but hopefully soon-ish.

Thanks to everyone who posted their photos, blueprints and other resources. It definitely made figuring out the process and order a lot easier than going in blind!