there's a nicer option: smelt the red cobblestone, and put that red rock into a carpenter supplied with a aqueous accumulator.
this way you just sit next to that machine and get all the clay out of it.
I just thought about a similar thing, I don't need the clay, but I need (I have a dense ore age that seems to be mostly stable... a little naussea on the surface) a lot of sodiumpersulfate. since the best supply for sodium is clay (and therefore redrock) I sit on a few stacks of lithium. and lithium burns very well in liquid fuelboxes. I think about setting up a boiler (my first one) with a bunch of different liquid fuel supplies, one of them will be lithium...