When I recharge my TWP cartidges, I remove the ridge on the ends that comes at the mold lines, to lessen the chances of leaks. You can feel the ridge so I remove it by "sanding" the ends of the tube.
You can tape a sheet of fine sandpaper to a flat table, and draw the tube end along the sandpaper, turning occassionally, and making sure the tube is kept square with the table top.
By the way, I don't use the spring as it compacts the resins and creates too much resistance in my TWP and pops the water connections sometimes.
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ICQ #30079114
Ray's Reef