Originally Posted by
merlinextraligh
It's the easiest way to start building wheels. Take the new rim, and tape it to the old rim, then transfer the spokes to the new rim one by one in the exact pattern of the old rim. Admittedly, you've got to ge the wheel dished, tensioned correctly, and trued. You could always pay a shop to help you get that part right.
Take the opportunity to lubricate the spoke threads and rim sockets with anti-seize (ideally zinc-based) or grease. Use an acid brush with half the bristles chopped off on the spoke threads; that may or may not fit in the rim socket in which case you can use a Q-tip.
Tape a nipple off, move the spoke, and thread the new nipple on to a consistent depth.
You can use a spare spoke to get new nipples on there. Some people thread a nipple on upside down and jam it against the threads, then but their new nipple against the fix one for installation where they thread it on until the spoke ends touch then grab the flats and remove the installation tool.
Note however this only works when the Effective Rim Diameters (ERD) matches, where the ERD is where the straight ends of the spokes end up after passing through the nipple bed by a few millimeters.