Ok, a few bucks, YMMV depending on what tools you have already.
$1 Nibco 604 Copper male adapter 1/2" NPT to 1/2" pipe (5/8" OD actual).
$2.38 for two pack. Hillman 3/4" stainless washers, item 21840 at Lowes
Short piece of 5/8" soft copper tubing but you can do it with a piece of rigid 1/2" pipe with a 90 degree elbow if you have to.
I already had the oring but a #314 is what you'd want to get.
The washer needs to be slightly filed open to get it all the way over the threads. After that, clean up the parts, apply an acid flux and silver solder the washer to the adapter.
The oring then goes on, through the kettle wall, then teflon tape, then the ball valve. If you can't get it tight, add the other washer between the kettle and valve.
$1 Nibco 604 Copper male adapter 1/2" NPT to 1/2" pipe (5/8" OD actual).
$2.38 for two pack. Hillman 3/4" stainless washers, item 21840 at Lowes
Short piece of 5/8" soft copper tubing but you can do it with a piece of rigid 1/2" pipe with a 90 degree elbow if you have to.
I already had the oring but a #314 is what you'd want to get.
The washer needs to be slightly filed open to get it all the way over the threads. After that, clean up the parts, apply an acid flux and silver solder the washer to the adapter.
The oring then goes on, through the kettle wall, then teflon tape, then the ball valve. If you can't get it tight, add the other washer between the kettle and valve.