How to make your own Harry Potter Quidditch Robes on polkadotchair.com...The costumes are made by making simple modifications to a basic robe pattern. I’m sure you can find a free tutorial online for a robe pattern if you don’t want to buy one, but since you can usually get sewing patterns on sale for as little as .99 I think it’s worthwhile to buy one. Simplicity 9877 is great for adults and Simplicity 3998 will work for kids.