How to build a mash tun cooler

Slide the hose clamp on first, put the barb in the mesh, and tighten the hose clamp as tight as you can get it.  Then screw on the endcap.  You can use teflon tape here if you like, but with this piece being inside the mash tun, if it leaks, there are no consequences, so I didn’t bother. On the other end, I attached the barbed to female connector in the same manner.

Barbed connector going into the mesh on the drain connection end of the hose
The completed connection after the hose clamp is fastened

The next step is to remove the drain from the cooler.  Mine was a simple unscrewing of the drain nut, and then pulling the plastic nipple out.  Be sure to save any rubber grommets, o-rings, or seals, as you can use them on your metal pieces you’ll use shortly.

Remove the old cooler drain before transforming into a mash tun cooler
Simple removal of the cooler’s plastic drain

Once you have the original cooler drain removed, insert your brass pipe nipple in the hole.  Use the O-rings and/or the original drain seal on the outside and inside, then screw on the washers to keep the pipe nipple in place on your new mash tun cooler.

Pipe nipple inserted with the O-ring attached
Pipe nipple installed with the original rubber seal and a new O-ring
mash tun cooler drain connection
Tighten the conduit threaded washers with a pair of pliers on each side for a water-tight seal

Now that your pipe nipple is in place, and has been tightened and liquid proofed with the O-rings, you can connect the mesh filter pipe on the inside of the mash tun cooler.

Stainless metal mesh filter tube connected to the drain hole