Here's how it was done :-) Regular blog readers might not be that interested in what follows - it's long and detailed!
Table of contents
Initial joinFinal notes
Main webbing strap and buckle
Stiffening in back
Final weather sealing
As far as possible I wanted to make the pannier out of things that would otherwise be thrown away. I used:
- 5 mesh onion bags (10kg-size)
- the equivalent of around 200 supermarket shopping bags. These must be HDPE (recycling code 2). To make the bag decorative, I included a lot of highly patterned bags kindly supplied from China by my mother-in-law. I was also able to obtain a few HDPE bags that were as big as the onion bags, which was really handy.
- 2 corflute real estate signs (the size they put outside houses for sale)
- other strong fabric (in my case, an off-cut from our curtains), about 65 x 40cm
- around 1.5m 2" velcro
- 2-3m of 2" webbing plus a 2" buckle (I had to buy this - the cheapest way was to purchase a luggage strap)
- about 1.5 m 1" or 1/2" webbing (mostly scavenged from old bike helmets and old bags)
- 6 buckles or belt slides (1" or 1/2" depending on the size of your webbing) - those I hadn't scavenged from helmets I got from an army surplus store, where they came complete with webbing.
- a galvanised metal washer with a central hole around 1cm across.
- duct tape - around 5m
- scrap wool - around 10m
- extra strong thread - I used a whole 30m roll
I also needed the following tools:
- curved needle
- darning needle
- strong straight normal needle
- towels and newspaper (or lots and lots of newspaper)
- baking paper (or you could use newspaper, but some ink would then probably transfer onto your fused plastic)
- marker pen
- tape measure
I chose to make a square bag (as opposed to one that tapered out) because it would be simpler to sew. It sits on the left-hand side of the bike, secured to the bike with six anchors and closing with a buckle. (As you can see in the plan below, the original plan involved two buckles. To minimise sewing, this was later revised to one buckle, but a 2" one rather than the original 1"). The top flap was designed to overhang the bag at both sides in order to better keep water out, plus there is a drainage hole in one of the bottom corners to deal with any internal spills. Other than at this point, all seams were sealed with duct-tape for water-tightness.
Martin had earlier installed running boards on the bike. From the running boards to the carrier is 410mm and the running boards are 720mm long. This defined the bag's maximum height and length. In the end, I made the bag 410mm high but only 640mm long as this was the maximum I could easily do with my materials. In retrospect it would have been better to make the bag a bit shorter so that it could hang above the running boards rather than sit on them - as it is, it has a tendency to thump on the boards when going over bumps. The bag is 150mm wide - a number chosen fairly arbitrarily but which is working well.
The bag is primarily made of plastic bags ironed together. This fabric is very strong but rips once punctured. To prevent this, each plastic sheet has a layer of netting at its core. My one concern with this material is how it will hold up to being in the sun long-term. I have noticed that HDPE plastic can become very brittle after a year or so in the sun. It's too early to say whether this bag will also deteriorate over time. An alternative 'upcycled' material would have been old billboard signs.
There is a sheet of corflute in the back of the bag to stop it flopping around. The bag can be used as a single open space or divided into two uneven sections using a moveable corflute barrier.
|My plans - pieces to cut from the plastic bag fabric and corflute|
Fusing the plastic bags
I essentially followed these excellent instructions. I put a big towel folded in two on the floor to protect the floor. I covered the towel with newspaper so no plastic would stick to it, then started layering plastic on top.
The plastic bags all have to be recycling number #2 (HDPE) to fuse well together. These are easily identified as they crackle when you scrunch them.
First cut the bags open so each is a single layer of plastic. I tried to start with a really big sheet (ideally the size I wanted the whole final sheet to be) as this made it easier to see where to put the other bags. Two more layers went on top of this.
|First three layers of plastic|
|Final three layers of plastic ready for ironing|
|Back side after ironing|
|Front side after ironing|
I was able to make all the edge pieces out of a single onion bag. The longer 'base' piece was made out of the part of the bag that included the label, so it didn't need so many extra layers of plastic.
|net for edge pieces|
|edge pieces complete and ready to cut|
|The two side pieces, each 410 x 640mm|
|The edge pieces - all 150mm wide; 2 @ 410mm and 1 @ 640mm long|
|The top flap. The section at the bottom of the picture attaches to the back of the pannier, the section at the top where there are dark-coloured flowers forms the flap on the front.|
Using wool, I sewed blanket stitch along all the edges of the side and edge pieces. This not only secures the edges but will later enable me to easily sew them together.
|one of the sides edged in blanket stitch|
I cut one piece of corflute to 590 x 360mm and two pieces to 100 x 360mm. I had intended to round the edges of these latter pieces (which will form the divider) but I forgot and it doesn't seem to be a problem.
The netting hadn't gone quite to the edge of the side pieces in some places and I decided to put these weaker edges at the bottom of the pannier where I thought they'd get less stress. I then pinned the side and edge pieces together with safety pins at the corners to check they fitted well together. This was a bad idea as the wool got tangled in the pins and were very difficult to remove without cutting the wool: straight pins would have been much better. I then labelled the front and back sides with marker pen (on what would become the inside) and drew arrows showing which way up they were to go.
|The main body of the pannier pinned together|
|Back and edge pieces joined together|
Main webbing strap and buckle
As mentioned in the supplies list, we used a luggage strap for the main webbing and buckle. That was not only cheaper, but meant we could get a rainbow-coloured one :-)
|melting the cut ends of the webbing to prevent fraying|
|The webbing was stitched to the top flap with back stitch using a straight needle, with an X in a box at the high-strain area by the buckle socket.|
|You can't see this well, but the webbing on the front face of the pannier was only stitched with an X in a box at the base of the face. The rest needs to be free in order for the length to be fully adjustable.|
Note that I chose to install the buckle such that you pull the strap downwards to tighten it. Whilst this feels natural, I now think it would have been better to install it up the other way. As it is, the lower strap drags on the ground when it is unfastened, meaning that you must always fasten it while riding, even if your load doesn't require that. Installing it up the other way would have made that unnecessary.
Stiffening in back
I made a pocket across the back out of old curtain fabric (anything that wouldn't rip whilst the pannier was in use would be fine). A piece of corflute was placed in this and the pocket stitched shut. This isn't a high-strain area I so the sewing was done in a long running stitch (like a tacking stitch).
I next sewed around the edge of the portion of the top flap that was to go over the back panel. I used wool and a running stitch. Once done, I sewed a strip of the 2" rainbow webbing along the top flap at the point where it folds down the back, this time using a small running stitch in the strong thread. This webbing goes over where some of the anchors will go and spread the strain they put on the pannier.
|top flap attached|
The pannier is attached to the carrier of the bike at four points.
|Pinning webbing with belt slides roughly in place.|
|Determining location of the attachment points in situ.|
|One of the belt slides in place. We eventually put one at each end of the carrier (as determined by the tube locations) and the other two evenly spaced in between.|
|Stitching the webbing in place. This required the curved needle and was very hard work as the webbing that came with our belt slides was very thick. I stitched an X in a box in back stitch as close to the belt slide as possible.|
|All four attached and cut roughly to length.|
|Upper anchors attaching pannier to bike|
There are two lower attachment points, one on the tube that goes up on a sharp angle up towards the carrier and one on the tube that goes up on a shallow angle towards the seat. These don't need to be particularly strong as they're not weight-bearing: they're simply there to stop the pannier from swinging out. We used 1/2" webbing, fastened in one case with a side-release buckle and in the other with a belt slide. The webbing and fasteners were scavenged off an old helmet.
|Pannier on bike ready to position lower anchors|
|The space is really tight! We chose to put the belt slide on the tube going up to the carrier as it has easiest access and the belt slide would be harder to do up than the side-release buckle.|
With the pannier on the bike, we drew along the edges of the tubes at roughly the height we wanted the anchors. The anchors will then be mounted at right angles to these lines.
|Tube locations in marker pen; anchors next to the marks ready to sew on|
To spread the load on the anchors, each was mounted on a scrap of 2" webbing. The anchor was stitched to this (using the same 'X in a box' technique mentioned earlier) then the whole unit stitched to the back of the pannier with running stitch.
|Lower anchors attached|
I stitched together the base and one of the sides (using the whipped blanket stitch technique mentioned earlier), leaving a small gap in the corner. I inserted a washer into this as shown in the picture below.
|Drainage hole from the inside|
|Drainage hole from the outside|
The divider was installed in the bag about one third of the way along. We expect that the larger of these sections will get the most use so this section is towards the front of the bike in order to centre the load. The divider needs to be able to sit flush with the side of the bag when not in use and to connect to the front divider when in use. This is achieved with the use of velcro.
Firstly a strip of 2" velcro was attached along the long edge of one face of the divider. I used self-adhesive velcro, but still stitched the top half of it to the corflute with running stitch. I expect the velcro will be subject to substantial force and I wasn't confident the adhesive would be up to it. The other long edge of the back divider was then pierced at 1" intervals with a darning needle. Wool was sewn through those holes to connect it to the fabric covering the back stiffener. Lastly the matching strip of velcro was stuck lightly to the velcro on the divider and the divider folded down to determine the velcro placement. Like the previous strip it was self-adhesive, but I again stitched down the top half of the strip to be sure it would stay put.
|Back divider with the divider folder back to show the velcro|
|Back divider in the position it will be whilst not in use|
The front panel was attached to the bottom edge of the bag (using whipping stitch to join the blanket stitches) and the remaining edge was also joined to the bottom edge.
|Outside view: front panel joined to bottom edge|
|Inside view: seams sealed with duct tape|
I attached velcro to the long edge of the divider as before (making sure to use the other side of the velcro so they would stick together!) and pierced holes in it. I then stuck the two dividers together and held them in place while I stitched the divider to the front panel (going right through) with wool. This was really hard as the space I was sewing in was very tight. It would have been much less awkward to simply mark on the front panel where the divider should go, but I was more confident of getting it in the right place if I did it in situ.
|Stitching the front divider to the front panel|
|Front divider opened out showing velcro|
|Front divider in the position it will be when not in use|
|Dividers as they will be when in use|
Note: The top couple of inches of the front divider ripped off the front panel when a too-large load was put in one of the pannier compartments. I have since sewn it back on, but this time I strengthened the top few inches (by joining the divider to the front with three stitches through each hole rather than one) and made the stitches independent of each other (i.e. each is individually knotted, so if one is damaged they don't all undo).
Final weather sealing
All remaining internal seams were then sealed with duct tape.
|Inside fully sealed|
It took several years to accumulate all the supplies for this project then several months to complete it (I have a chronic illness so could only do about 30 minutes on this project most days) but I'm so pleased with the result :-)
Whilst assembling the pannier, I realised that the plastic bags hadn't fused properly in a few places and there were gaps where the netting was exposed. When this happened, I added in more plastic as follows.
|Plastic panel with exposed netting|
|Plastic wadded up over a hole.|
I then put a newspaper under the panel and baking paper on top and ironed it to melt the bag.
Velcro on flap
My original intention was to put large-ish patches of velcro on either side of the flap so that it could flop shut without needing to use the buckle. I did start doing this but ran out of thread before I was done. Before I could get more thread, Martin started using the pannier and he's finding it fine without. However, if you install the buckle on your pannier up the other way you might find velcro useful. As it is, in our case the buckle always has to be done up so the velcro is unnecessary.
I also wonder about later putting a handle onto the top flap for carrying it when off the bag, but it rarely leaves the bike at the moment so thus far that has been unnecessary.
|The first use for the pannier was carrying home a new wheel :-) You can see here how far the top flap can extend to accommodate large loads. My first velcro patch is also visible on the front.|
|The most common use for the pannier - bringing home the weekly vege shop (and occasionally some flowers for me!)|