For anyone who's interested and likes to make plastic bag slings, I've developed a method of melting strips of plastic together for braiding. (I 'spose you could just tie them, but when I do this I get bits sticking out of the braid.) All that's needed is some card, some normal aluminium foil used in cooking and a desk lamp with flat glass in front of the bulb.
1: Get a strip of card, long and about 5cm wide. Cut a flap the width of the plastic strips you want to melt together into one end of the card (green lines). Leave a narrow gap and cut the rest of the card to the width of the lift-up flap.
2: Cut a piece of foil to a bit wider than the plastic strips. Wrap this around the end of the card,
below the lift-up piece.
3: Put the ends of each strip of plastic below the lift-up bit of card, resting on the foil and coming in from either side. They should overlap by however much you want to melt together.
4: Fold the long left part of the card over the foil, plastic and card, back and forth. (brown-red lines)
5: Turn the lamp on, wait for the glass to heat up, and press the foil underside of the thingo against the glass. Your fingers should be on the other side, pressing all the layers of card together. The strips of plsatic dangle downwards.
6: Wait ten or so seconds then take the whole lot down. The plastic should be fused together well enough to braid it as a single piece. If your fingers get hot, the plastic has probably melted by then.
WARNINGS (and stuff): Obviously, the lamp is hot. Don't burn yourself. It's probably best to work near an open window and keep your face away from the melting plastic. I'm not sure if it gives off fumes. Their's also a possibility the paper will catch fire, but I think it's unlikely.
Just be careful if you try it.