Purchased a quart of liquid self etching primer to do inside of tubes. Taped off ends of tubes and poured primer, slowly, while turning tubes. Primer was very thin and actually seeped out of the taped up ends. All four tubes are on end to let all the primer run out. Small tubes actually were completely filled with primer. Primer messed up marks on outside for drilling rivet holes so I had to clean everything off and will re-mark tomorrow. Also primer buildup on one end of each tube so I had to clean out with acetone and re-prime with paper towel soaked in primer.
