Metalwork options for creating a pannier for my bicycle

[ToolbeltDandy]

I would like to create something in the rough shape shown below. My bike already has a pannier rack on it and I'd like to affix this structure to it, probably with plywood or similar forming a platform on the bottom, either side of the wheel. My question is what sort of steel tubing should I use (e.g. round vs square). The grey bars represent optional bracing which may or may not be necessary.

It would be great if I could do it this without special tools but there's an art facility in Edinburgh which I may be able to use if necessary. I have a small gas torch which I could use to braze joints to avoid welding. Could I braze square tubing to avoid having to try to bend it?

 

[foxhole]

You could assemble with copper tubing, but they are so cheap to buy why bother?

 

[ToolbeltDandy]

I have pannier bags which I use to carry shopping home. I would like to build this so I have an open platform for bulkier loads. I think copper would maybe be a bit too soft and bend out of shape under load?

 

[foxhole]

Anything heavy enough to buckle short lengths of copper is going to buckle your back wheel, you have not given any dimension but any open platform will be a few inches wide so not hold any bulky items.

 

[foxhole]

Maybe you need a trike

http://www.flickr.com/photos/rodriguez5000/5292397161/#/photos/rodriguez5000/5292397161/lightbox/

 

[Burnerman]

Copper has a tendency to work harden and fracture when subjected to vibration or other stresses......aluminium would be fine apart from the difficulties when joining it.
If you want to go ahead, thin section mild steel tubing would probably be best, with the joints brazed.
John

 

[mattylad]

I would hinge the lower sections so that they can be folded up.


And in that case you can use ordinary panniers/rack and add plywood side that can then have piano hinges and bottoms added - with support straps.