Pack Frame Build Questions

Macegl

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Dec 2, 2016
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I've been toying with the idea of building a duplex style frame. I figure my current pack has about a year left on it, and with my sewing abilities I figure I better round up supplies and get an early start.

Reading Tartan and 5shot's posts from their builds couple years ago has given me some great ideas, and really helped with the thought process.

Just a couple questions:

For the aluminum stays 5shot posted a link to a supplier on ebay that sells pre-bent stays 7075 aluminum stays for the Marine ILBE, has anyone used these or have you bent your own?

Next on the HDPE sheet, can you heat it up with a heat gun to shape it? Or does it require another method. I have made things out of PVC heating them up and forming them, but I've never tried HDPE.
Another question on the HDPE sheet, is 1/16" HDPE is rigid enough or would you use 1/8" like the previous version of the duplex? I realize there would be a weight penalty, just curious if there would be any benefit to using a thicker plastic.

Appreciate all the good ideas on this forum, there's a lot of first class craftsmen on here
 

colonel00

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I can't help with most of your questions. I'm a DIYer at heart but some things are worth paying for and for me, a frame is one of those. That said, I have made my own stays for my Duplex frame. Kifaru's aluminum stays are just thick enough to make shaping a pain. I needed to change the shape to fit me better.

So, I just went to Home Depot and got an 8' section of 1" x 1/4" aluminum stock and made my own. While the 1/4" thickness is slightly less than what Kifaru uses (I forgot but maybe 3/8") I haven't had a problem with it.

Granted, I had the pattern already from the Kifaru stays I already had. Right now, it's traced on the wall of my garage. If you are interested, I can see if I can trace it on some paper and send it your way.
 
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Macegl

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How hard are they to bend to shape? One concern I had with the pre-bent stays was if they didn’t fit I’d have to shape them anyway.
 

5shot

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I reshaped the ones that I bought off eBay... wasn't too difficult. No need to heat the HDPE, it isn't hard like Kydex.

Sent from my XT1585 using Tapatalk
 

colonel00

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It's not that it's hard to bend the aluminum, regardless of thickness. I just found the thicker Kifaru stays a bit harder to tweak just in the right spots, like near the ends. I'm sure you could rig up some jigs or something to make it easier. I just found the 1/4" thickness a bit easier to bend and tweak to just the right shape.

One other thing I almost forgot about. I read about Kifaru releasing a new frame soon. You might just wait and pick up an "older" frame on the classifieds. I have no issues with the current design. I'm sure the new one will be great and maybe lighten things up but there will be plenty of frames up for sale soon at a good enough discount.
 
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Macegl

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Dec 2, 2016
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Thanks Colonel, I’ll keep an eye on the classifieds, but it’s pretty satisfying when someone asks where you bought a piece of gear, and you tell them you made it yourself.
5shot, would you go with 1/16” hdpe or 1/8”?
 

Tartan

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I bought both my aluminum and HDPE from mcmaster-carr

3/16" x 1" 6061 i believe and 1/8" frame sheet. 7075 would be an upgrade I'm sure, but one I probably wouldn't notice.

no need to shape the frame sheet, the stays will do that. The curve that the stays put in the frame sheet also help stiffen it side to side. I think the 1/16" is plenty stiff. It will bend a little bit, but it doesn't seem to affect anything.

I'm still playing with the shape of my stays, but I think I'm finally pretty close. I did pack out a cow elk this year and while not enjoyable, I didn't have any hot spots or anything like that.
 
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Macegl

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Thanks all, I’ll get some supplies on order and hopefully post some pictures of some progress.
 

pods8 (Rugged Stitching)

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I'm a DIYer at heart but some things are worth paying for and for me, a frame is one of those.

Ditto. I sew up quite a bit of accessories and bags but frames don't seem worth it. Good ones I'm sure take some rounds of R&D to get all the geometry and materials dialed in and cost of buying all those things one off. Sure you can make something functional but is it as comfortable as a refined frame from the various manufacturers? Maybe. I'd rather make up all kinds of fun bags and such with that time though. :) Only time playing with a frame crossed my mind is making up something for my kids when they get a bit older but aren't into adult size frames, but with that I know they aren't going to be loaded with the weight that adults potentially are carrying so the ergonomic refinements aren't as critical most likely.

Regardless original poster GOOD LUCK! and keep us posted. :)
 

Tartan

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just to add some thoughts. To me, the frame itself was the easiest part of the whole pack build. If you imitate kifaru like I did, you're just building a cordura sleeve that slides over an hdpe sheet. If you have a truly industrial machine you can even sew the webbing through the hdpe, but from the experience with mine, it isn't necessary. I had over 80lbs in my pack and didn't pop a single seam. The hardest part is just trying to figure out what order the pieces need to be sewn together.

now, the belt, shoulder straps or harness, lumbar pad, etc... that's where the comfort really comes in. I may have gotten lucky, but I've hiked with my pack and a kifaru back to back and was very happy with how mine felt. I however spent quite a bit of time with cardboard and foam mock-ups before I sewed a single stitch. I zoomed in and stared at countless images on the web of different pack designs from kifaru, hpg, sg, etc to mentally reverse engineer how they were made.

It took several hikes with some weight, would make an adjustment, and repeat. Luckily I had access to a friend's kifaru at that point and I made some tweaks to my lumbar pad and stay shape that really smoothed things out.

It's certainly all about what you want to get out of your diy. I can see the argument for both sides. There's definitely a comfort knowing you're starting with a good base if you build off of a frame that's already out there.

I'm excited to see the new kifaru frame, just so I can figure out what changes they've made and if it could help me make a better pack.


keep us updated. Even if it's just the little things. you never know what may help somebody in the future.
 

pods8 (Rugged Stitching)

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Yeah when I say frame I mean the whole thing including the straps and belt, which good foam and geometry seem to make/break a design and trial/error could eat up material costs figuring it out nicely. But there is certainly satisfaction at the end if someone chooses that path, esp. making a unique design.
 
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Macegl

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I get it, and if I found a screaming deal on a duplex frame I would have a hard time not just buying one.

However there are a couple things I would like to change, and when I fork out a bit of money for something, its pretty hard for me to make modifications to it.

My sewing machine is a singer 301 so I'm pretty sure sewing through the HDPE will be a no go. So for now I'm planning on sewing it up like Tartan did.

Quick question on how cordura is sold, when they say it is by the yard, is that one square yard i.e. 36"x36"? Or is it one yard of 60" width fabric i.e. 36"x60"? I had always assumed it was by the square yard, but some of the descriptions I have been reading on ebay make it sound like one yard of 60" fabric.
 
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Macegl

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Good to know, I would have bought way more than I needed to. But I would have had a lot of material left for building things.
 

jyukai

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Nov 25, 2016
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Planning to DIY my own bag soon, but running my own hack 'frame' with Kifaru's bags in the meantime. Using a Greyman Tactical 10.75" x 17" rigid molle panel with HPG shoulder straps and Prarie belt. Love how the panel slots perfectly into the hyphalon sleeves of Kifaru's bags, with lots of options for attaching additional compression straps. This only works well with the smaller bags like the apollo, 22mag and nomad though.
 
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When I had a kifaru tactical duplex frame I wanted to make a shorter version and just use the shoulder straps, hipbelt, and lumbar pad that I already had.

The project came out great,* super functional. It was very time consuming for a novice like myself. I didnt make any templates or lay anything out, just jumped right in. It was not the best way to approach a frame on my own.

Some things I learned.

I used 1/16th hdpe because I knew my machine (1960's kenmore) couldn't punch through 1/8th hdpe. I prefer the thicker framesheet after using both. It resists barreling* better. My machine couldnt do 1/16th thickness, as a matter of fact, but I picked up a sewing awl and it worked great albeit slow and time consuming. I use it on all my projects7 now to reinforce high stress seams. Here is a link: Speedy Stitcher Sewing Awl
I used the small needle #130 with the fine waxed polyester thread #160.


My personal opinion is the best aluminum stay size is 3/16" × 3/4" 7075. That is the size McHale uses on his custom packs. McHale Alpine Style Packs However acquiring this size is like hearing a unicorn fart. My step dads owns a welding shop and he couldn't find any of his suppliers that carry that size in stock. The stays from staymakers on ebay are great stays, they are the size that HPG uses, 1/8th x 1" 7075, 24" long for the Ute and 28" long for the Qui Ya. Using those stays in the kifaru frame didn't work that great, they have much more bend then the OEM Kifaru kifaru stays. The systems are just different including the way the stays are supposed to be bent. HPG stays follow the shape of your back more closely than Kifaru, due to not having a large lumbar pad. 1" x 1/4" 6061 can be found fairly easily (home depot, tractor supply etc.) and about ten bucks. They are also almost an exact match to what Kifaru uses. They can be a chore to bend, having a bench vise helps.

Finding the right foam, or good enough substitute is tough. Most pack manufacturers use EVA foam which is pricey and hard to find in small quantities. Then sewing through the foam is not easy without a good machine.

I think a lot of what the other guys have said is really a good idea. Buying a used frame is the way to go. Making bags and pouches is awesome and totally doable for a diy project. The frame is a big project and not really cost effective when you are starting from scratch and without an industrial machine to punch through some thick stuff.

Good luck and let us know how your project takes shape.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
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Macegl

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Dec 2, 2016
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Thanks for the tips, I have pretty much decided to use 1/8" HDPE after watching some of the Kifaru videos comparing the tactical vs hunting frame.

I worked up a cost list over the last couple days for the materials I will be purchasing to build the frame/suspension (with some extra material added in, for mistakes I'm sure I'll make). Its coming in right around $200.00, just for the materials, so its easy to see why these companies charge what they do.

The good news is if I don't make too many mistakes, I'll probably have enough to get a bag out of it as well.
 
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