Hi folks - I customized some leather satchels to make saddlebags.

I had some aluminium plate sewn into the backs of them, but evidently I should have used bigger (deeper) plates, as the bottom third of the bags are kinda 'sagging in and under' the bottom edge of the metal plate towards the bike/wheel

What I'm thinking is I might fit another metal/plastic plate to the outside of the bag to keep it straight and stop it sagging in towards the bike - they'll be invisible when fitted anyway, so not bothered about looks.

My question is, should I just be using aluminium sheet again or is there a suitable plastic material (like the kind of stuff they make chopping boards out of, for instance) that might be even lighter?

If so, what would it be called and how thick would it need to be to provide a similar sort of stiffness to, say, 3mm aluminium?

 

I'm not an expert, really, but I did sell some sheet goods (gasket materials and such) at my former job, so I have some experience.

Something like UHMW Polyethylene might work for what you're looking for. 1/8" thick will still have some flex to it, but be relatively stiff depending on how large or small the sections are. You can get it in black and it's cheap enough from McMaster Carr that you could buy some to experiment with and not be out much if it didn't end up working.

Here's a link (the sheets are on the right): http://www.mcmaster.com/#uhmw-polyet...heets/=12fnad0

 

Nice - thanks for the tip

 

I have cut up old bed liners from pickup trucks and purchased black garbage cans from Home Depot for similar things to what you are doing. These are nice sources because they have the angles already in them.

 

I am not a plastics expert, but I have used plastic storage bins cut with tin/metal shears to custom fit inside soft bags before. Just rigid enough to hold the shape desired and not taking up a lot of space or adding weight.

Good luck...

 

The best performing product for this application is ABS. 1/8" thick sheets are thin enough to not be intrusive, but very rigid and light.

Rather than cut individual sheets for each side of the bag, form a "U" shape that can be inserted. If the opening doesn't allow the "U" to fit, make two "L" shaped that can be screwed or glued together after installation.

http://www.amazon.com/gp/aw/d/B00AKJ...+plaatic+sheet

 

Perfect! thanks

 

You could also use kydex (like they make holsters with) you can get it in various thickness and you can also mold it to just about any shape w a heat gun.

 

Yeah. Good stuff too. It's a little tougher than ABS, but a bit more expensive and slightly harder to work with. But only slightly on both accounts. It's a great option.