This is one of the most complicated tip I have given out so far and it takes some getting used to , but the results speak for themselves. Remember this is a complicated method and as all the method should be tried on a scrap first to get the hag of it.
This method does work best on seams that have a reinforcement strip to hold the two ends together but I have used it successfully on "roll together joints that simply overlap.
Cut out all the parts for the tube, that later will form the rockets body.
Glue the glue strips in place following the instruction for the model kit.
Pre-curl the the paper sheet by gently rolling it around a smaller wooden dowel. Do this to secure, that it holds it's shape before you starts adding glue to it.
Take a strip of low tack or any other type of masking tape and cut it into small strips as shown. Then attach the strips to the inside of the part just before assembly As long as the strips are placed about right it doesn't have to be exact, just stay clear of any circular retainer rings that will go in later.
Now align the centerlines first and work out the ends. This takes some care and maybe a few try. Push the two edges together, while attaching the masking tape with a dowel or finger.
If the tape pulls up a little paper when you reposition the tape, don't worry. Remember, that it is hidden on the inside, where it will not show.
Now you have a tube with the unglued ends pulling away from each other. This is ok. Just double check that when you force the two egdess back together that the seam is in alignment.
Here comes the tricky part. Pull the two parts away from each other by slightly squeezing the tube.
While the seam is open lay several stripes of glue up and down the reinforcement strip not getting too close to the very end of the seam where the two ends meet, you don't want glue oozing out when we do the next step.
Push lightly from the center out just to tack down the whole seam, work quick but not sloppy.
Now take a dowel and roll over the tacked down ends as the glue dries, this will allow a uniform glue joint. I sometimes put down a piece of wax paper or foam to collect the glue that sometimes oozes from the seam because of the force being used by the dowel.
Now you are done. The result speaks for itselves.
Remember, there is no need to remove the tape. You will probably tear the model by doing so. The tape can stay harmlessly inside never to be seen by any one and you will end up with a perfect seam as the proof shows.