I decided that my vessel would be made out of a 52Qt rectangular igloo cooler. I chose this due to local availability and price. Due to the shape of this vessel, a batch sparge is preferred over a fly sparge. NOTE: I have not included pictures, but may add later. [Edit]: Just to be clear, I do feel that a circular cooler (like those Gatorade ones) usually work a bit better, especially with fly sparging. I also chose the size of the tun (52 Qt.) so that I can mash grain for up to 10 Gal batches.
Equipment to buy:
1x 52 QT. Igloo rectangular cooler
1/2" Brass Ball Valve
1x 1"x1/2" threaded brass nipple
1x 1/2" FIP to 1/2" Barb
1x 1/2" MIP to 1/2" barb
1x 1/2" MIP to 1/2" barb
2x #15 Rubber O-Ring
1x 4' Stainless Steel (SS) braided dishwasher/toilet water line
Length of 1/2" Hot water transfer tubing
Prep SS Braid
1. Saw off the hose connectors on the Dishwasher water line (both ends) You may want to tape up the ends to reduce fraying of the SS braid
2. If there is an outer plastic tube surrounding the SS braid, use a razor blade cut a single cut down the length of tube and peel off the outer tube.
3. Remove the inner tube. Use pliers to slowly pull the inner-tube out, while pulling the outer SS braid down the inner-tube. Start slowly, working the one end of the braid down the tube. As you compact the SS braid, it will loosen and slide off easier. Think of a Chinese finger trap
4. Using a a hose clamp, attach a 1/2" FIP to Barb
5. Pinch off other end
1. Remove spigot from cooler (usually held in by a plastic nut)
2. If you are lucky, there should already be a 1/2" hole left from the spigot
3. If not, use a 1/2" hole saw to make a hole where the spigot was
4. Optional: Drill a 1/2" hole on on the top of the cooler to allow for incoming water from HLT
1. Place the 1/2" threaded nipple in the new 1/2" hole
2. Place #15 o-rings on both sides of the cooler wall
3. Attach the SS braid assembly to the inside of the cooler
4. Attach 1/2" MIP to 1/2" barb to 1/2" Brass Valve
5. Attach the 1/2" Brass Valve to the outside of the coolers 1/2" nipple. Careful not to over tighten.
6. Attach 1/2" transfer hose to 1/2" barb for out-flow
7. OPTIONAL: If you drilled a hole in the top of your cooler, you can assemble another nipple (take measurements! the lid is usually thicker than the walls) and 1/2" FIP to barb assembly (you could use a smaller barb) to allow for a closed cooler during sparge. Note since this is above the liquid level, it does not necessarily need to be liquid tight.
Test and Adjust
Prior to first use, I recommend testing the tun to ensure it is water tight. Fill the cooler with water and look for leaks. If there are leaks try adjusting the tightness on both sides on the cooler wall. Note that leaks will occur from both over and under tightened assemblies.
Below is a picture of the MLT with grains waiting for use. Note, I did the optional step of a nipple through the top. I also assembled a SS braid for incoming hot water, but this doesn't really do much - it does NOT evenly distribute water. No worries, I'll be batch sparging. But the photo does show a SS braid, so it might be useful. More photos will be uploaded in the near future, but the MLT currently has a fermenter I do not wish to disturb sitting on it
Up close with the SS braid. Note that's a 1/2" Barbed to 1/2" FIP. The FIP screws onto the nipple that punches through the cooler wall. A #15 O-Ring sits between the FIP and cooler wall to create a seal.
Up close with the brass valve. 1/2" MIP to 1/2" barb connected to the valve. The valve is screwed into a 1 inch length 1/2" threaded nipple that sticks through the 1/2" hole where the original spigot lived. Sealed by #15 O-Rings on both sides. Essentially the same on the inside, minus the valve, a female thread instead of male, and using the SS braid instead of plastic tubing. Oh and use a hose clamp on the inside barb/braid
MLT from the outside. Nipple\barb on top connected to my Hot Liquid Tun.