sew on nametags

Question

My daughter who is 11 years old is going to sleepaway camp on Thursday morning after tisha-baav. I need to sew on nametags on her socks so she won't lose them in camp washes. Can I do it on Tisha-baav after chazot? I have so much else to do on Wednesday so whatever I can possibly do before would be very helpful. Thanks for this wonderful site!