I think I see what you are talking about. I assume you are using a multilayer CA finish? the last thing I do after I have finished the blank is to use a knife or a skew and cut a groove 'just past' the joint between the barrel and the bushing. This helps to establish a 'break line' just beyond the barrel and may leave a little of the CA protruding off the end of the barrel. This MUST be removed before pressing the pen together. Some people sand it off with sandpaper mounted to the flat side of a barrel trimmer or with a dedicated tool. Personally, I trim it off with a sharp knife or chisel.
That is a pretty pen by the way - the two-tone amboyna looks great.
Yeah, I think I didn't sand it enough. Back to the shop and practice some more.
I think I learned a bit about pitting a good finish on it while making it though. I did it at our local pen group but just got the CA on. I finished it at home 2 days later. The CA had set up hard and was a lot easier to finish and gave a nice smooth finish and wasn't cloudy. I may start leaving them 24 hours before finishing them in the future.
I think you should use delrin finishing bushings. There is one member called johnnycnc who sells them, with those you won't have to separate the tubes of your pen with the bushings, they won't stick together as they are smaller. Usually when I am done, I just sand the ends of my pen tubes to make them straight as glue can build up. That should take care of that white line problem. ;-)