Make Your Own Cylindrical Stuff Sack
As a follow-up to his tutorial on making a simple rectangular stuff sack, Dave Helbig returns with this step-by-step guide to making your own cylindrical stuff sack—a shape that’s perfectly suited to cinching into a cargo cage, a handlebar harness, or underneath your saddle. Find detailed instructions here…
Words and photos by David Helbig
In this second stuff sack tutorial, we’ll take a look at cylindrical stuff sacks. They are a bit harder to sew than their rectangular counterparts we learned how to make last time, but I find they offer several advantages. They are easier to stack onto each other in large bags, fit better in cargo cages, and in my opinion they just look better. Let’s get to it.
Making A Cylindrical Stuff Sack
Here’s what you’ll need to get started:
- A basic sewing machine
- A sharp pair of scissors
- A lighter
- Several mini clamps, like those you’d find in the kitchen
- A straight edged ruler for measuring and cutting your fabric to size
- A utility knife for cutting your fabric
- Around 0.5m of fabric
- A 15mm buckle
- 30cm of 15mm webbing for the roll-top closure
- 20cm of polyethylene plastic (or more of the same 15mm webbing instead)
- 30cm of any size webbing to add MOLLE loops (optional)
Note: I understand that not everybody has polyethylene plastic at home. Some people use other kinds of plastic, such as something cut from an old binder, etc., but be aware that they will wear and tear over time. Instead of a substitute plastic, I recommend using a second length of 15mm webbing. It will certainly do the job, but it just needs to be rolled more tightly to work effectively.
Before You Begin
Sewing a round bottomed stuff sack requires some more advanced sewing skills (which we’ll dive into later) and also some math.
Your bag will be made out of two pieces of fabric: the bottom (round) part and the upper (rectangular) part. To know the exact length of the upper fabric we’ll first need to calculate the circumference of the bottom fabric we choose to use, using the formula: C= d x π, or if you prefer, C = (2xr) x π.
For this tutorial, I used a little plate from my kitchen with a diameter of 13cm. So, in my case, C = 13 x 3.14, which means my bottom piece has a circumference of 40.8cm.
As such, I needed to cut out an upper part measuring 40cm (the circumference) x 45cm (you can use any number here depending on the height you want your stuff sack to be).
By cutting out a d=13cm piece, the actual stuff sack will only have a diameter of 12cm, since we have to account for a 1cm seam allowance. Calculating the circumference of a d=12cm circle (37.6cm), shows us that even if we use 40cm instead of 40.8cm, we won’t have to add any extra seam allowance for the upper fabric since we have a difference of 2.4cm.
I wouldn’t recommend going smaller than d=15cm, otherwise the opening could be too small for you to easily access the bag, in addition to making it harder to see into. Anything smaller than a 15cm diameter also results in a bag with a limited storage capacity.
Some (very) personal guidelines:
- 15-20cm diameter: Stuff sack for cargo/anything cages, or to neatly organize your clothing inside another bag.
- 20-30cm diameter: Stuff sack to cinch to your saddle rails, depending on your tire clearance.
- 30cm+ diameter: Stuff sack to cinch to your front or rear rack.
Now, let’s begin with the fun part…
Start by cutting out the pieces of fabric calculated beforehand.
- A round bottom part: d = 13cm
- A rectangular upper part: 40cm x 45cm
Sew the 40 x 45cm fabric on the long side together by folding right side on right side (so the two 45cm parts are on top of each other). Leave about 1cm of seam allowance.
Step 3 (Optional):
Stitch down the seam allowance along one side. This will facilitate applying seam sealant later on, if desired, and also gives your stuff sack a nicer look. Note: Be really careful that you don’t sew the two sides of your stuff sack together!
You should have a tube that looks like the above right.
Step 4 (Optional):
Applying MOLLE webbing:
Turn the bag right side out. Only one seam should be visible from the outside. Place the webbing right above your seam (as shown in the photo) and tack it down by going back and forth. No need to go wild here! Once should be enough since you won’t be pulling on the webbing. Voilé Straps are 2cm wide, so leave at least 2.5cm between your stitches.
Note: To speed up this process, don’t bother to cut the string after every back and forth pass. Just lift the needle, slide the fabric, and restart.
Sew on the round part by placing right side on right side. Go really slowly here! Do 3-4 stitches, readjust the round part (left hand) and keep feeding the upper (blue) fabric through (right hand) and redo 3-4 stitches.
Note: Respecting seam allowance is quite tricky while sewing round stuff, so you might end up with either a tiny bit too much or too little fabric (or maybe because my calculation is not 100% precise). Folding the required fabric just a tiny bit should help.
Turn your bag inside out and fold it so your seam is placed in the middle. Place the plastic stiffener on the upper side and curl the fabric on one side around it twice. I usually trim the plastic once at this step since I don’t always respect my own seam allowances and might end up with a smaller or bigger bag. Using little plastic clamps is really helpful here to keep things in place.
Match the other side by folding it twice and use the clamps to hold it into place.
Stitch everything down. I recommend starting on the non-plastic side, as this will hide the start and end of your seam later on.
Turn your stuff sack inside out, then adjust the length of your webbing to fit the width of the bag.
Stitch the excess lengths of webbing to the lower portion so everything is fixed into the appropriate length. This will make it easier to sew on the entire webbing without it slipping.
Carefully clip the webbing into position at the top of your stuff sack.
Sew the webbing onto your stuff sack. Start with the upper and then the lower side. Odds are, one of your buckle ends will still be a bit loose at this point.
To firmly affix and reinforce the ends of the webbing, do a little back and forth as close to the buckles as possible.
Cut all remaining threads and burn the ends using a lighter. Congratulations, you’ve made your first cylindrical stuff sack. Sit back and proudly admire your work!
About David Helbig
David Helbig is a bikepacker based in France who spends his free time volunteering for a local DIY bike festival, riding around town on a rusty old bike, or heading off to the mountains to hike, mountaineer, and ride with friends. He’s been getting more and more into making his own gear and exploring the vast opportunities that traveling by bike offers.
Looking for more DIY projects? Check out our guides to making your own fanny pack, fire starters, stem bag, ultralight beer can stove, cycling cap, and lots more by following the hashtag #MYOBG. And if you made a stuff sack using this tutorial, please share a photo of it with us in the comments below!
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