I use a 10 gallon Rubbermaid Cooler for Mash tun with a cooper manifold. On brew day I wrap the manifold in a sanitized 5 gallon paint strainer prior to installing it in the mash tun.
I preheat the mash tun with hot water from the HLT (My Brew keggle). Next I get the temperature of my grist. Temp in hand I enter data into Sparge Pal (iPhone) or web:
Batch size: 5 gallon
Grain Bill: 12 lbs
Boil Time 60 min
Mash Thickness 1.25 qts per pound
Grain Temp: 66 (example)
Target Mash Temp: 154
Mash: 3.8 gallons at 168 degrees
Sparge: 4.7 gallons at 170 degrees
Works for me.....
My current plan is to do Iodine tests on the mash to determine if
one hour is the right amount of time to complete starch conversion.