I was just forced to make mine because shipping will cost me more than the original stuff.
I made several versions, they all works fine.
I use various kinds of soft plastic like PVC or the kind that you put on the kitchen floor (I don't know name in English), and cover material with some kind of inkjet substrate like HP tracing paper or HP vellum, therefore the printed surface come in contact with clean material that is also supposed to be used for printing.
I made several different constructions with different diameters of core.
First I used cardboard core from the paper roll it works fine at the begging of the roll, but need more time to de-roll when paper approach its end. It was 2 inch core = 5 cm.
For second construction I used cardboard core that has 4 cm, that works great on all degrees of curling.
I tested core that was 2 cm in diameter, it was too extreme and some papers got strips like it was bent over the edge of table - but it did not crack picture layer or destroy it or made any other harm to the image itself. I don't use this construction any more.
Than I made one without core with soft PVC - this is miracle - it works in the second with any kind of paper in any curl - but you need to be very gentle with pressure. Because there is no core it is possible to bend paper if you put to much pressure on it, just gently roll the paper and it is flat. Due to lack of hard core it is possible to adjust diameter so it is very useful for all degrees of curl, and all kind of material. My favourite construction. I just glue HP tracing paper on each side of PVC in the way that layer on which it is supposed to be printed is outside.
At the end I can say that I save a lot of money, learn a lot about mechanic strength and resistance of various papers and have some fun with my leftovers from calibrations, but the main point is that it works very well.
Of course I can change my mind if I have opportunity to work with the original, but I doubt it.
