
My trusty inner tube bum bag has been in near constant use now for over a year, accompanying me on walks and bike rides and other escapes from being stuck home during a pandemic.
So I was gutted when I broke the zip. It was totally my fault: I stuffed it really full with a wispy plastic bag on top, which got caught in the zip. Instead of taking care I just tried to force it closed/open, whacking a tooth out of place. Soon the zip just came off one side.

I couldn’t just bin the bag. I’d saved the inner tubes that made it from landfill, washed and sewed them up, pairing them with a lining made from a pair of secondhand trousers. It was such a useful thing and meant a lot to me, so I decided to replace that zip.
I’d never done a zip replacement before, but thought of no better time to give it a go. As I’d constructed the bag I knew where it was attached and more or less what would need to be done to put a new one in…I thought.
I definitely learned a lot in this process (translation: some things didn’t go exactly to plan!).
Choosing a New Zip
I love the combination of inner tube and metal teeth, so I rummaged through my stash of secondhand zips for one I liked the looks of. With a lot of repairs you have a big choice: whether to try to hide the repair or show it off. I decided to ask Instagram:

Thankfully you guys chose contrasting. To be honest, I would’ve gone contrasting even if the votes had gone the other way, but it was nice to see nearly everyone agree.
When things break it’s so easy to just toss them in the bin. Repair can sometimes seem like a subversive act. I love highlighting the mends and adjustments I make to garments to make people think.
I did decide to use black thread, though. There was going to be a lot of hand stitching and I’m out of practice so I thought it might turn out a bit rough.
Taking Out The Old
I like to do my mending work in front of the telly in the evening. This time, I had some help removing the old zip from the bag. Tilly decided to keep me company.

It made things so awkward and slightly frustrating, but she’s so tiny I can’t say no! There was a point I did have to set things aside because she got very cute and demanding for a fuss.
Zips are where I start with a lot of bag making, they tend to be really sewn in there as they’re under a lot of stress. So I carefully unpicked the stitching all around the opening. It was attached along each edge – long and short – sewn twice to the lining, and stitched in along the join on the bag’s short edges.
But it didn’t take long to remove, despite Tilly’s ‘help’.
Adding the New Zip
Adding the new zip is where things started to go wrong. For some reason I got it in my head to sew through all the layers at once. Maybe I thought it’d be faster and less hassle?
I was so wrong.
I used a double sided sticky tape (designed for sewing) to attach the zip to all the layers. If I were to do this again, I’d start with the lining only, and then go back and stitch through the exterior as well. This mimics how I sewed the bag together to begin with, so I’m not sure why I went rogue here.
Doing both sides at once meant I needed to keep an eye on a lot of different seams, but it did come together eventually.

While the tape can be frustratingly sticky, it can also shift against the inner tubes. I found it moved as I worked, so I had to undo some stitches periodically. Eventually I also put some sewing clips (a great alternative to pins for inner tubes), which helped a great deal, but there are still some areas where it’s a bit wonky.
All of the seams were resewn by hand. This opening is too small and fiddly to work through on my current machine (at least when the bag is completely assembled), and I wanted to go through the existing holes in the inner tubes to reduce damage – you can see them really well in the photo above. I reassembled with a quick running stitch to get everything in place, and then came back again later to fill in the gaps.

I’m really glad I chose black thread as I somehow managed to turn a straight line wonky, even going through the original holes as much as possible. It’s a talent!
Another downside to doing everything at once was it created a flap of lining. I was worried it might get caught in the zip, so I eventually went back later and did a (more or less) invisible stitch line in red to tack it to the zip tape:

I also reinforced the short edges of the bag with a few lines of stitching through those same holes. That’s probably the part of the bag that’s under the most strain, so I wanted to be sure it wouldn’t come undone.
The End Result & Summary

Despite all the stress I’m so happy to have my bum bag back! I really missed it for the week or two it was out of commission.
I’m so happy I’d chosen a black lined bag for myself, so I was able to use black thread on the repair. Some of my stitching looks ok on the outside, but really dodgy on the inside.
If you’re not the one using it day to day I doubt you’d notice. And it hasn’t impacted the usability of the bag at all. If I ever have to do this again, I’ve learned some valuable lessons I can put to good use doing a better job.

So if you’re thinking about doing this yourself:
- Decide what look you want: contrasting or matching (matching thread is always a good choice for hand stitching if you’re out of practice)
- Take your time – Don’t try to do everything at once!
- Make sure your pins/clips/tape/glue are secure
- Be proud of you work and the fact that you’re saved something from landfill!
- Try to ignore any little mistakes, no one will notice them but you!
And if you’re interested in your own bum bag, you can find the rest of my limited stock here. While I love the design, I’m on a pause making any new ones until I get an industrial sewing machine.