This spring I brazed up the main tubes for a touring frame and decided not to vent the top tube joints. Not a problem. Did not experience any blow outs from heat. Of course I am unable to get in the top tube to flush it, but that will be another chapter in this story at some other time.

In a previous frame I used 3/4 hole at the head tube to vent with. The seat stays were not vented either. Does not seem to affect anything from were I sit. Long term corrosion may be an issue, but I doubt it.