Ready for the torch. The flux is a bit lumpy cause it's dry. I didn't feel like walking all the way to the house to get water. It works all the same. I preheat the tubes with a blowtorch before applying flux. Just enough so the tubes "sweat". This way the flux dries instead of boiling and falling on the floor. Both the flux and the brass are from Henry James.

Here is the seattube sleeve all cleaned up and ready to braze. I'm leaving about 1/4" of ST sticking out so I have somewhere to feed the brass.