Let me begin my stating that this was NOT my idea......I read, or heard of this method for pre-washing yardage some time ago. I wish I could remember where because I would love to give them credit. This little time saving trick worked so well for me I had to pass it along.
I had a piece of fabric just over 9 metres long, needing to be pre-washed. You know what happens when you throw that full length of fabric into the washer......you end up with a big twisted mess that has to be unwound to then go into the dryer where it just twists up again so that by the time it is dry you have to spend a long time at the ironing board trying to get rid of all the wrinkling.
To avoid this, a little prep work is all you need. Here is what I did.
I opened the fabric up so that it was the full 45" long, serged the raw edges to prevent unraveling, and then began accordion folding in roughly 1m lengths along one selvage edge. I set my machine to a long stitch, used a contrasting thread in the bobbin and proceeded to stitch the selvage edges closed through all layers. ( Not sure if it was only supposed to be done at one end but I did this to both ends)
What went into the washer was a piece of fabric that measured about 45 x 40 inches and 9 layers thick. I checked it a couple of times during the wash cycle to make certain it stayed in that shape. When it came out of the dryer I unpicked the basting threads and left the piece draped over the ironing board still folded, to finish drying (the selvage area was still damp)
The only pressing I will need to do is what I would generally when beginning any project. You can bet I'll be using this method to pre-wash my fabrics in the future