Lynn's DIY Ultralight backpack

[Lynn LeFey]

First off, I have to say that I'd LOVE to share photos of this project. And i will. JUST as soon as photobucket stops sucking. Until then, I'll have to just use text to get this thread started.

Some time back, I got a chunk of Tyvek housewrap from a friend of mine, and thought it might make a neat material for a lightweight backpack. So I made a bag and straps and... it sucked. It was made entirely of duct tape and Tyvek, and the problem was the connection point of the shoulder straps. The duct tape kept pulling away. I set the failed experiment aside, feeling like it could only work if I could sew layers of Tyvek together.

But the idea never fell out of my head. It just ruminated. The more I watched videos of 'Ultralight' backpacks made of Dyneema composite fabric, the more I wanted to make my Tyvek pack. Those cottage industry ultralight packs were well over $200. I could make one out of Tyvek, almost as strong, almost as light, for a fraction of that, I was sure. Sure enough, I started hearing rumors of people who'd already made packs of Tyvek. So, I wasn't 100% crazy.

So, for my birthday this year, I got a 'budget', about $250 to get whatever. Some of the 'whatever' that I got was a used sewing machine, a 3'x100' roll of Tyvek, and some GOOD duct tape, in this case a roll of Gorilla tape and a roll of FiberFix.

Since I had pretty much no idea what I was doing with a sewing machine, I started learning, and my first project was a poncho/bivvie out of Tyvek. After sewing, I sealed the seams with the Gorilla tape. The weight of it, at 6' x 7' is about 12 oz. Not bad.

I jumped right in on the backpack prototype. I called it the 'ULSurvive' pack. It is basically the same design as a lot of the ultralight minimalist packs. It has a big central compartment, waterbottle holders on either side, and a mesh pocket for wet gear. And that's it. Closure of the main compartment is roll-top. No zippers to mess with (or fail). It has a series of tabs made of ribbon to hold very light cordage and act as compression straps. The goal, if one was to be stated, I guess would be this; Backpack capacity of something like 40 liters, and weight capacity of 25-30 lbs. Weight of pack under 1 lb. Cost of pack as low as possible. Easy to repair in the field.

I worked for six days building it. It was made of Tyvek, bits of ribbon, bank line, 'toggles' made of plastic coat hanger, and duct tape. When it was complete, I was reasonably happy, and before I put on duct tape reinforcement, I decided to load it with 20 lbs and shoulder it just to get a feel for the fit. Testing the materials made me come to a conclusion that any place where cord had to connect to duct tape was best done by inserting one of the plastic toggles to keep the tape from tearing. The toggle distributed the load across the width of the tape.

And...

The main body tore where the left shoulder strap connected. This was from heaving the pack up by one strap to shoulder it.
 

So... I... (sigh) sewed on a patch, reinforced the pack with duct tape, and tried again. It worked, but the dimensions felt wrong. The main body was too bulky. Also, the construction method was monstrously complex.

I set it aside and did a rapid-built second prototype. This was just to test some changes to the shoulder straps. This pack wasn't a complete build. The main body didn't extend far enough for a roll top, BUT the entire thing came in at 7.2oz. and was pretty amazingly sturdy.

The trick, it seemed, was to have a sort of mesh of duct tape that bore the weight, NOT the Tyvek. Break strength of Gorilla tape is about 140lbs for a double layer. It will MOMENTARILY hold my entire body weight before breaking. That is amazing.

One change I made was that the bottom of the shoulder straps connected to the bottom of the pack by paracord, instead of bank line. Not that the bank line wasn't strong enough. It was just that the paracord allowed me to make a double d-ring buckle with two galvanized washers for easy adjustment of the shoulder strap length.

My THIRD prototype is still in progress. It consists of three separate pieces. The first is a sling, made of duct tape. The second is the main bag (this time, made of blue tarp). And the third is the shoulder harness. I separated the harness from the sling so it could be adjusted based on the height of the wearer.I have yet to add the cordage that will hold it all together.

And with all this, I might refine a single goal... Instead of 'cost as low as possible', change that to '$5 of material from the dollar store'. Which, when I use the blue tarp instead of Tyvek, might actually be doable. I don't think any pack I made for myself would use the tarp material. That's just become a goal for what is doable for those with very limited resources.

[Aloha]

I've seen some project involving Tyvek.  Some are interesting while others, not so much.  Not trying to be a smart arse but with a Bday $250 budget, why not buy a pack?

I'm all for making stuff and projects are super fun but  .  I've found that my personal threshold for making things is, the time factor.  I'm not terribly busy but my time is worth the dollars spent sometimes. 

I do hope this didn't come off negative. 

I am very curious about your project 

 

[Lynn LeFey]

I didn't just buy a pack, because these are going to end up going into our vehicles as emergency bags. I need 4 of them.

Also, with that budget, I also got mylar bags, o2 absorbers, a food saver and roll of bags for it, a 55 gallon drum and syphon for it, a bunch of emergency food, and a load of other small things I can't think of off the top of my head.

Also, this is something to do. And, very likely, will also lead to me eventually making my own tents and such.

No, you're not coming across as negative. It's a fair question.

[Aloha]

 .  I see backpacks all the time.  We picked some up for car emergency packs for family.  We load them with the basics and give them to our family members.  We also give them a print out of other items that could go into the bags.  I love the idea of Tyvek projects and seen some neat tents. 

I love projects.  I'm currently hoarding pallets to try to make a pallet floating deck.  I began then stopped collecting broken tiles to make a mosaic.  IT was getting out of hand  .   

[Lynn LeFey]

I own a lot of smaller bags. Jansport and such, 25-30 liter size. I just don't think they're big enough for what I want.

Something I got to test in all of this was a $5 pack from Dollar General. It's about 25 liters. Everyone anywhere has said what complete garbage it is, but I do 2.3 mile walks, sometimes 3 a day, and have been carrying it a while. I've completed 20 walks with it loaded to 13 lbs, and just completed 10 walks with it loaded to 15 lbs. It's still doing fine. I added a waist strap, but that's just to make it more comfortable. The only problem with it, or anything similar, like Jansport bags I often find at thrift shops, is that they're just too small.

I have to say, though, if you can get by on a very small kit, it really isn't a bad bag. And not one I'd worry about someone wanting to steal, or feel all that bad about if someone DID steal it.

[Steinar]

Very interesting! A quick search on DuckDuckGo for tyvek backpack yielded links to at least a couple of other DIY projects, so you're certainly not alone in experimenting with the material.

And I would like to add I appreciate people posting here using their words. Words are rather better at conveying intent than what is possible with pictures alone. 

[MadPlumbarian]

I got a old used sewing machine as a graduation gift waaaaay back in 97, my grandmother made a job of it and I’d watch her, so I knew my basics.. I did make a backpack from a backpack a few years back, nothing great, but I want to buy fabric and make my own from scratch! I even have sketches but need to get fabric..
JR

[Lynn LeFey]

I have some ripstop nylon and poly webbing that I intend to use to make a more durable version of a pack at some point. Once I have a good design sorted out.

[MadPlumbarian]

The bag I want litterly isn’t a backpack but a panel that I can attach little bags to like a first aid kit, yet also has a compartment that opens and expands Incase you want to carry anything..
JR

[MadPlumbarian]

Kinda like this,
JR

[pfrsantos]

 

[Steinar]

 

No, it isn't. 

[powernoodle]

as soon as photobucket stops sucking.

That's going to be a long wait.   

[microbe]

Pretty cool project, but as stated above, we need pictures :-)
Please hit up https://imgur.com/ and spend 2 minutes to create an account,
then you upload the image, then you click on "images" in the menu, click on your uploaded image and then click on "copy" for the generated BB code, then paste it here in your reply.

 

[Lynn LeFey]

Okay... well, photobucket is SORT of working. I can't copy links so, URLs it is, I guess.


Here's the first prototype, back view. The straps here are two layers of tyvek with padding sandwiched in between. All the cordage is 50 lb bank line. There is no frame, but the design is made so a foam pad can be slipped in between the straps and body of the pack, making it more rigid and giving padding. There is also a wooden toggle on the lines between the shoulder strap and bottom of the pack to adjust it.
http://i105.photobucket.com/user/lynnlefey/media/IMG_20190226_103429614_zpsmnp4mrud.jpg.html


Here's the same pack, front view. You can see the duct tape reinforcing the bottom, and the drawstring closure of the top. The two side pouches are different. One is permanent, one is three flaps held together by more bank line. The idea was to allow eight the carry of a water bottle or to allow pass-through for long, skinny items. There is also a big mesh pocket with drawstring to cinch it up. Testing has convinced me it needs to be larger. I made it out of dollar store laundry bag mesh, and on a final version I would DEFINITELY use better material.

http://i105.photobucket.com/user/lynnlefey/media/IMG_20190226_103418231_zpsbebkfsxk.jpg.html

The little red tabs of ribbon are visible on both pics. These were for criss-crossing compression straps made of more bank line.

This next pic is the back of the second prototype. The shoulder straps are two layers of Gorilla tape with Tyvek in between. No padding. Instead of a wooden 'tent toggle', I used two galvanized AAA washers to make... I don't know what it's called, a Double D-ring buckle? I'll snap a detail pic later. The paracord used is gutted out dollar store cord. The gutted outside sheath will hold at least 150 lbs.

http://i105.photobucket.com/user/lynnlefey/media/IMG_20190226_103510797_zps22bzejdu.jpg.html

Between the previous pic and the next one, you can see the sort of sling of gorilla tape reinforcing the outside of the bag. Since this was just to test the 'cargo sling' idea, I didn't bother with side pockets or the mesh pocket, or the top, which I've decided to switch from pull cord to roll top. Another change I made to simplify the bag is to make the main body from one piece. On the first prototype, the back, bottom, and front are one piece, and the sides are sewn on. In the second prototype, the sides are folded over from front and back, so there's just one seam on either side, held together with duct tape.

http://i105.photobucket.com/user/lynnlefey/media/IMG_20190226_103518377_zpsojtasgkt.jpg.html


And, finally, the third prototype...
http://i105.photobucket.com/user/lynnlefey/media/IMG_20190226_103704789_zpslk81qsyb.jpg.html

This is three separate components. A sling that's 10" wide, that will comprise the front, bottom, and back of the pack, a separate H-harness that will connect to the sling, and a 'dry bag' that the sling will support. The bag is again a roll top. The harness and sling are two layers of gorilla tape with blue tarp material between them. I might cut out the tarp material in the hollows of the 'rungs' of the sling. Dunno. The sling will attach to itself along the sides. You can see the big black patch which is the reinforcement for the bottom of the pack. It might be a little hard to see, but the sling also has two loops to thread a waist strap through.

[MadPlumbarian]

Interesting,,
JR

[microbe]

Cool proto's, Curious about the next iteration, and how you will replace the ductape.

[Lynn LeFey]

eventually, the harness/sling portion I imagine will be nylon or poly webbing.


EDIT: Oooh, hey... seatbelt webbing looks like it goes for 60 cents per foot. Hmmm....

[Lynn LeFey]

And, I figured I'd add a pic showing the detail of the strap connection. You can see the plastic 'toggle' wrapped in duct tape and the reinforcing FiberFix tape over the gorilla tape just at the end of the shoulder strap (this is on the second prototype, but is 'typical'). You can also see the adjustment point created by the two washers.

http://i105.photobucket.com/user/lynnlefey/media/IMG_20190228_153802543_zps3odrslh8.jpg.html

What I fund is that despite the fact that Gorilla tape is extremely strong, whatever I use at the end will tear through without another reinforcing layer. I also tried this with the same washers as seen in this photo, but they tear through more easily than the plastic rods. I also couldn't use the bank line because the washers won't grip it to make a secure buckle. No big deal. Gutted paracord in this location won't add tons of weight and DOES add tons of strength.

[SteveC]

Lynn do yourself a favor and ditch Photosmurfit. 

Most of us have switched to imgur as it works very well