I had been looking around for info about how to do the 10-Gallon Rubbermaid cooler Mash tun conversion for 1/2" fittings instead of 3/8 and the info is spotty and scattered far and wide. Figured I would post what I came up with for my system that I'm very happy with and post the links to where I found it all. With this setup, you do NOT need the white rubber seal that comes with the cooler, nor any additional O-rings to help a 3/8" nipple "fill out" the stock hole on the cooler once the original spigot is removed. It is all-stainless/all high-temp safe as far as what touches your mash/wort. Since the internet is already rotting my brain, I don't want any additional chemicals leaching into my beverages to make it worse.
You could use any 1/2" MPT barb fitting you want to connect hose direcly but I went with the F-style Camlock
so I would have that kind of connection everywhere:
(One) 1/2" Ball Valve
(One) 3/4" cut washer from Home Depot:
(measures 52 mm wide overall diameter with 21 mm inner diameter, about 2.5 mm thick.)
(For reference, a web source would be here
(One) 1.5" Long 1/2" Diam SS pipe nipple
(One) 1/2" Inner Diameter silicone washer
(One) 1/2" (large diam for cooler bulkeads) SS washer
(One) 1/2" SS Female threaded hose barb
A stainless braid and hose clamp would be fine here for batch sparging but I went with a false bottom because I intend to fly sparge eventually.
False Bottom: Video Link: http://www.amazon.com/gp/product/B004B7GIV8/ref=oh_o03_s00_i00_details
from Amazon with 3/8" SS Barb:
I connected the 1/2" bulkhead barb to the 3/8 barb on the false bottom with
about a 6" length of 3/8" ID thermoplastic hose
The hose fits very tightly around the 1/2" barb and moderately tightly around the 3/8" barb, which allows me to remove the false bottom for cleaning. I have not had to use any hose clamps on it.
I was able to reduce my mash tun deadspace (undrainable liquid volume) by half (from 2 quarts down to one quart) with one simple addition to my mash tun:
I used a short length (~1.5") of regular 5/16" vinyl siphon hose, trimmed one end as shown in this pic and wedged the other end into the bottom port of the false bottom. This effectively maintains a siphon for longer and lets you drain down closer to the bottom without choking off flow. Depending on how domed your false bottom is, you may need to adjust the length of this small piece of hose so that it is just flush with the cooler bottom when in place. You don't want it preventing the SS false bottom from making good solid contact with the cooler bottom all the way around, yet if you make it too short, you lose some wort by having the siphon break sooner. Obviously this works best if your cooler is on an absolutely flat surface. I plan on finding a piece of copper or SS tubing to use instead of the vinyl hose so that I can be sure it won't collapse in any way.
Hopefully this helps some of you save some of the time I spent digging and researching, and buying extra unnecessary washers and fittings.