Don't leave those ikea bags out in the sun, they fall apart rather...quickly....
I came here to say this... Those FRAKTA bags ( http://www.ikea.com/us/en/catalog/products/17228340/ ) are 100% polypropylene (thin strands, even). Polypropylene breaks down under ultraviolet light. The fact that the weave of the cloth is made from fine strands of polypropylene means that it will break down very quickly in the sun. There's a "fix" though that should be good enough for a camping trip or two! Coat the b…
Still seems that economically speaking it might be cheaper to create such a backpack from a more suitable cloth instead.