1. Remove the existing drain plug from the cooler. The plug in my cooler was actually two parts that threaded together between the inside and outside of the end wall. If you don’t have a drain plug, use a _” spade bit to bore a hole through the end wall. The center point should be located evenly in the horizontal direction, and about 1-1/2” from the floor of the cooler.
   
   
2. Thread a conduit locknut unto one end of the 2” nipple as far as it will go. Place one of the washers unto the unthreaded section of the nipple. Put this three-piece assembly through the hole in the cooler, so that the washer lies flat against the inner wall.
   
   
   
   
3. OPTIONAL, BUT ESSENTIAL STEP: The washer must lie flat against the inner wall, but because of the curve where the cooler wall meets the floor, the washer may need to be cut or ground down. I had to do this to ensure a snug fit. I used a Dremel with a cut-off wheel and then a grinding stone to remove about 1/8” from the washer.
   
   
   
   
   
   
4. Prepare some plumber’s epoxy as a long, thin rope. While holding the nipple assembly centered in the hole, press the epoxy into the gap around the nipple. Use a small flat screwdriver to push as much of the epoxy into the hole. Remove any excess epoxy, and smooth the surface so it’s flush with the outside wall.
   
   
   
   
5. Place the other washer over the outer portion of the nipple, then thread a conduit locknut on until it compresses against the washer. Slightly tighten the nut to hold the assembly in place while the epoxy sets—about 20 minutes. (NOTE: While the nut tightened down enough to hold the assembly firmly, I cut a rubber gasket to match the size of the metal washer out of a sheet of gasket material. This was placed between the outer wall and the washer during final assembly.)
   
   
   
   
6. While the epoxy sets, determine the position for the baffle that connects the manifold to the outlet valve. In my case, the outlet was fairly low, so I placed a tee about one-third of the way down one of the “even-numbered” runs in the manifold. The tee is turned about 45&Mac176; toward the center—if the tee was in the middle run, it would have to be oriented straight up, but would then be too high above the outlet. A short CPVC nipple connects the tee to an elbow. From the elbow, an approximately 6” length of CPVC connects to a _” CPVC to _” NPT female coupler threaded unto the inside of the nipple.
   
   
   
   
   
   
   
   
7. Remove the outer locknut and washer. Check if the epoxy has fallen away from the gap into the cooler insulation. If so, fill the holes with some more epoxy. Replace the gasket (if needed), washer, and locknut.
   
   
8. Wrap the outer threads of the nipple with Teflon tape. Thread the ball valve unto the nipple.
   
   
9. Wrap the threads of the brass _” NPT male to _” ID vinyl tubing elbow coupler with Teflon tape. Thread the coupler into the outlet of the valve. A length of _” ID vinyl tubing can then be attached to the coupler.
   
   
   
   
10. With the ball valve closed, pour a couple gallons of warm water into what is now your homemade mash tun. Check for leaks. Check that the ball valve functions properly. Clean everything with hot water and dishwashing detergent to remove any gum left from price tags and dirt and dust.
    
    
    
    

Conclusion

Construction of this mash tun requires little in the way of money, time, and handyman skills. The final product enables you to create high-gravity 5-gallon batches, and low- to medium-gravity 10-gallon batches. If you’re looking for a way to get into all-grain brewing without investing a lot, you’ll enjoy and appreciate building your very own mash tun. Good luck, and happy brewing!

• Called: Colin Brougham
  
• Lives: Cadillac, Michigan
  
• Works: Northern Michigan CBS affiliate, commercial/promo producer
  
• Brews: 6 months experience, partial-mash batches of every flavor of the rainbow; soon AG!
  
• Other: Kept on task by my wife, Rachel; when not brewing or building brewing gear or talking about brewing, I’m attempting alchemy with food, mishandling a camera, or assaulting a guitar