Lots of Flux. and tin your ends. Then more flux. On small stuff I use a electronics liquid flux. You can dip the ends right in a small container.

Just my 2 cents

P.S. Super looking box. I keep playing with the idea of making one from scratch. But I think I'll wait till I get a little seasoned and see how much cra... (stuff) I end up taking into the field.

See ya

Del