Ways of keeping curls in pin straight hair?

So I have tried almost everything, sleeping in bendy rollers (Painful, looked silly not curly and lasted about 2 hours). I tried sleeping in rags, lasted all of an hour. I use hot rollers now and get the curls to last 3 hours or so at the most with hair stray and mousse. Hot curling irons have no affect, litter ally 10 minutes of lasting even when I use the hair spray. Any methods or brands of products would be highly appreciated. Thanks!