New the the AHA forum. We needed this BADLY!
I think this thread would be the best spot to ask about about Mash Tun design. I am planning to build a recirculation brew-stand this next year.
I've recently abandoned my 10 Gallon Rubbermaid cooler (glue has separated at the bottom and there is a upward bulge of the innner plastic liner which makes it impossible to use a false bottom). I recently bought a Coleman Extreme 70 qt Cooler. I have temporarily fitted it with my Bulkhead and ball valve connected to a Bazooka Mash Screen that I had used in the 10 gallon rubber maid.
I tried to build a manifold, but became frustrated. I tried using 1/2 Copper tubing and fittings, but those I think are too big for this cooler to build an optimal manifold. I think I may try again with 3/* tubing. Thought I could do 4 long collection tubes, but they would rest against the sides of the cooler because the fittings are sized such that any closer spacing isn's possible.
I don't think that the Bazooka Screen would support a RIMS/HERMS setup because of the same comments posted here concerning channeling - you would get non-uniform channeling of the wort feeding into the recirculation circuit, and likely also compaction of the grain I suspect because of the nature of the Bazooka Screen.
I could attempt to figure out the optimal design myself for a slotted bottom copper manifold design but I would rather tap into the knowledge and experience here to minimize further frustration, and maximize enjoyment (and efficiency). So is there any awesome design I could copy, or is there any advice or blueprint that is out there for building a HERMS system with a Coleman 70qt Extreme cooler for a mash tun?