You could start with new material and make it like a giant cushion cover similar to these.
But for this bed for Karma I recycled an old hammock whose ropes had started to fray. The canvas was still like new though.
You could also use old curtains with tabs as long as the material is sturdy enough for a dog's bed. (This isn't Karma. It was Chanelle keeping an eye on my husband.
You'll meet Karma later in this post)
I folded the material in half and found some old pillows around the house that would fit well.
I read somewhere that dental floss makes a great thread for heavy work so I gave it a try here using it to stitch the pillows together. I overlapped them by a few inches.
Now with the wrong side out sew the 2 sides together at each side just a little longer than the pillows you want to put inside. Leave about 4 inches not sewn at the tab end and leave the tab end opened.
Fold 1 tab end in to almost the size of the pillows and sew it down like this. I hope these instructions are making sense.
Now turn the work right side out and put the giant pillow inside.
I used a few lengths of cloth ribbon to make ties. I just sewed them onto the pillow at several intervals and tied the tabs together, making the cover easy to take off and wash every now and then.
And this is Karma our 2 year old boxer/shar pei mix baby. She's our rescue furbaby and she is very lovable.
She's learned a lot in the month that she has been with us, but clearly chewing is still a bit of a problem.
Oh well, almost good as new!