Oh, anywhere from 30 minutes to three days But seriously, if you've haven't read the thrust arm stories here, it might be worth a look, or laugh. It will entirley deoend on how 'stuck' the ball joint end is in the steering arm. Are you planning on using a puller? pickle fork? 10lb sledge?
I assume you're looking for the arm itself and will replace both the ball jint and bushing??? As such, you can ruin the balljoint in your quest to remove it.
Good luck in the muck,
Dave