Kev888 wrote:Yet more very useful progress!
For continuous (or fly) sparging, the false bottom would ideally cover the whole base to maximise evenness of flow, but an inch around the edge is quite trivial - I seriously doubt you'd notice any difference at all. With batch sparging there will be even less impact (in fact some would prefer breaks in the drainage to help reduce compaction when draining).
Though yes, if it were to move around (say when mashing in) and ride up on the radius at the edge of the base then you could see a gap letting more/bigger bits of grain out than is normal (you will always get fine particles when initially running off). If that happens, some method of keeping the FB central may be needed; maybe some spacers around the edge or a small pin poking down into the central/bottom drain? But nothing too tight or rigid in a way that could prevent the weight of grain pressing the FB firmly against the pot base.
Hope the test goes well. If testing with water, you can normally expect that heat loss with grain will be a little better.
I like the idea of keeping the fb central using a pin or rod down into the outlet. Maybe a SS bolt with washers? It could also handily plug the hole in the Fb where the upward elbow outlet has been removed. Obviously it would also have to be narrow enough as to not inhibit too much flow into the bottom drain. Decisions, decisions... Thanks Kev