Opening corded sacks

[Mike Barnes]

Not strictly DIY but I bet someone here knows the answer.

We get bird food delivered in 20 kg paper sacks that are closed by a stitched paper strip - the sort that has one thick brown cord and one thin white cord and a rather simplistic notice saying "To open, hold tape and pull cord".

When I get it right, the string almost falls off, but most of the time I struggle for a few minutes then resort to cutting the whole top off with a pair of scissors. There is clearly a knack to opening these things and I haven't got it.

Which cord should I pull? Does it matter which end I start? Am I supposed to unpick anything to get things started? Etc.

[Andy Dingley]

It's chain stitch, rather than the lock stitch on a domestic sewing machine.

Here's how it's made.

you study that, you ought to be able to work out which end you need to attack it from.

Yes