I made a u-part 3 weeks ago. I sewed the tracks onto a spandex dome cap but also used a glue gun and glued some tracks underneath around front edges of the cap and the leave out area.
The glue sticks/glue gun isn't the same as Super Glue.
So far, the glued tracks are fine. I washed it last week w/out any problems. I didnt soak the wig cap/base when I washed it tho, I was very gentle w/ that area. I don't use a lot of product on my real hair and usually just plain water on my weave hair.
I'm pretty sure I saw this question answered in the comment section on the YouTube tutorials as well. I researched this thoroughly, watched at least 10 different YouTube tuts REPEATEDLY before deciding how to make my wig.
I love it..