I should have spent some time cleaning up my work area, but brazing is more fun.
The seat tube is in a 1 1/4" piece of tubing held in a Park stand. That way I can rotate it -- with a gloved hand of course. I added some flux after this.
My goal is to have the brazing filler as smooth as possible, particularly where it hits the tubes. It's really easy to leave a small lip right at the edge of the filler. The trick is to get rid of that discontinuity while brazing instead of having to file and sand it off and risk cutting into the tube. I thought this looked good, but it will have to wait until I get a chance to soak the flux off.