Though it's a slight possibility since concrete does shrink a bit as it dries, I couldn't guarantee that it would shrink enough that you could reuse the metal bands to make more stepping stones.
Though I'm not sure what idea you are going for, I have seen concrete pouring tubes sliced and used to make stepping stones.
I spent many minutes researching this method and couldnot come up with any information. I would then just try another stepping ston whats the worse that will happen.Nothing gained nothing lost.
Ive been searching for larger, circular forms for stepping stones myself. I haven't tried it yet but saw enormous circular pans that are drip trays for hot water tanks. Those can be sprayed with oul or release agent and used repeatedly. I would suggest some reinforcement in the concrete.
@Leigh I took a scrapped stainless steel clothers dryer tub, covered the outside of it with the cement and peat moss recipe, let dry-cure, painted black extior paint, planted a tree many years ago and still have the now pot with tree and it is happy growing in it.
Why not try lining them with plastic wrap?
A mold, is a mold. Why can't you reuse it?
concrete is NOT as strong as it sounds. Put some sort of lubricant on the band for insurance of release. if bands are large diameter maybe rods or a reinforcement (fiberglass type) sold in the concrete department should be added to the mixture,-- How about using the ground where the Stepping Stone will be as the mold? Dig the wanted shape--fill with concrete, cure, step on and wallaaa! done.
The ones I've made, have left the band on, but can't see any reason you could not remove the band to re-use. Only, I'd make the stone in place where you intend it to stay using a fairly dry mix, and remove the band immediately the same way you use the pathway molds that do cobblestone or brick patterns.
Once the concrete dries there's not much hope but I like the look of the rusty band in place. Also, notice that the bands are a little bit wider on one side - made to fit the curves of a barrel. Put the wide side down so it will slip off easier,