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.
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.
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.
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.