To make the holes are made in the mason jar lid, first sand away the coating on both sides of the lid. Don't try to drill the hole. Instead, take a skewed chisel and cut a 6 pointed star in the lid (looks kinda like an askerisk...). Poke a tapered center punch into the star and enlarge the hole. Six "petals" will be formed. Make the holes so that the petals are formed on the jar side of the lid. Size the hole so that the tubing is a tight fit. Do both holes and insert the 2 pieces of tubing. Put the lid aside the jar and eyeball where to make the crimp. I used a pair of dikes to cut and crimp the tubing in one step. Clamp the bottom ends of the tubing into a vise and ensure the ends of the goose necks are kinda close together to allow the lid's band to be placed over them later. Using a knife then some needle nosed pliers, straighten out the "petals" at the edges of the holes so they contact the tubing. These petals will reinforce the joint between the tubing and the lid. Smear some paste type flux on both sides of the lid and solder the tubing to the lid with lead-free solder. Exercise caution when soldering the outer tube to avoid melting the gasketing on the lid. I soldered by heating only the goosenecks. After the solder flows into the joints, quicking and gingerly brush the side with the petals with a flux wetted brush to remove excess solder. Don't brush the upper side- you want a bead of solder around the joint and wiping with a brush will remove this bead.

Clean the assembly with dishwasher detergent, hot water, a toothbrush and some sort of swab for the interior of the tubing. Follow with several flushes of hot or boiling water. Don't assemble the hopback and pressurize with city water pressure tho'- you'll likely create a glass grenade!

Stretch out a copper scrubbie a bit and insert the center, output tube into it. I cover the scrubbie with some fairly fine nylon netting to enhance filtering. Wire the scrubbie and (if you use it) the nylon netting to the top of the tube.

USING THE HOP-BACK
Put the lid assembly atop the jar and lift it just enough so that you can pour/stuff whole hops into the jar. I fill the jar and pack them in just a bit. Count on using 1 ounce or so. Put the band on and clamp it down. I put the hop back down stream of a counterflow chiller so that it helps in removal of the cold break. The traditional location is in the hot wort path so as to extract aroma from the hops. While the wort is still boiling, put a copper racking cane into the kettle. I use slotted 3/8" copper tubing loop shaped manifold for racking but a simple cane made from 3/8" copper tubing scrubbie and nylon netting on the end of the end also works. connect the racking cane to the input side of the counterflow chiller and the output of the chiller to the input of the hop-back with 5/16" ID vinyl tubing. (Hint: get a cup of very hot water and dip the business ends of the copper and vinyl tubing to be joined. Start the heated end of the vinyl tubing over the end of the copper tubing then use a dry rag or such to twist/slide the vinyl tubing further onto the copper tubing.) Another piece of vinyl tubing goes from the output of the hop-back to the fermenter. I put a clamp type valve on this line. I sanitize chiller, hop-back and connecting tubing by running boiling wort through the whole thing then capping the fermenter end and pitching the runnings back into the kettle.

PERFORMANCE DATA
The bottom of my kettle is just over 4' above grade and my chiiler has 20' of 3/8" copper. The flow through the whole affair is pretty slow- just over 1 quart per minute. I don't think you would want to go much faster or the hop-back could clog. Oh yeah, after I turn off the burner, I whirlpool the wort and let it sit 'til the hops and break are nicely piled in the middle of the kettle. I use a 8 gallon enamel kettle which is relatively large in diameter. I think this enhances the whirlpool effect.