Lots of people have been wondering about having a floating ring on top of the water. The creator of Peachy Printer has answered the question.

QUESTION
Nils Fromm asked:
possibility to save on the amount of resin:
Do you think it is possible to have a "floating" ring on top of the water, in which the resin is then poured, so that we don't have to cover the whole surface of the water tank? e.g. the tank is 10" x 10", but the part I want to print is very small, thus uses little resin. If resin is only inside the floating ring, the size of the container is irrelevant. Floating ring has to be held in position of course, but that is easily arranged.
Just an idea on minimizing resinwaste.
Your thoughts?

ANSWER:
@Nils Fromm
Yes. That is a wonderful idea, we see no reason why it would not work, but we have not tried it yet. As you said the floating ring could float around, so it would be best to guide it along the z axis with a couple of rods.