I've used a hardboard (cardboard) with a sticky
face to it. After you have washed, pressed, and prepaired your work for framing, you peal off a covering and stick, very carefully your art work to it. I've seen it at Michaels (a craft store).
It comes in different sizes and makes your work
look great. Then find a frame to fit it and your done. Good luck! Oh, be sure and work from the center out as once it is stuck, getting bubbles out is hard.