Are pull ups helping?

i want to build a build some arm muscles and iv been doing a decent amount of pull ups each day(around 100). i can do a good 3 sets of 15 with my own body weight but i want to build muscle so today i started doing some pullups with a backpack with 10 extra pounds in it, with the backpack i can only do like a couple sets of 5 each set if that. will this help build muscle if i keep doing it with 10lbs extra until i can do like 15 in a row and then add another 10lbs and keep doing this for a while until i decide its enough? i dont have access to a gym so im limited to home and i have a pull up bar. im 5'6 140lbs and kinda skinny so i wanna put on some visible muscle. any tips?