Would you be able to gave a bit of insight how you made your pen?
I'm happy to share.
I stumbled on this method while researching polymer clay on Youtube. I will post a link to the video at the end of my post. Technically, the video is about making Jewelry, but when I saw an intermediary step, I instantly knew I wanted to make a pen like what I saw on the screen. I have not achieved my goal, but it wasn't too bad.
First, I created a thin strip of clay with a gradient of gray at one end and white at the other. The strip was about 3cm wide and about 30cm long. I rolled up the clay strip starting with the white end, and ending with the gray - this left white in the middle, and gray on the outside. I then wrapped this roll in a thin single layer of Black clay. Once I wrapped it in the black, I rolled the roll back and forth, gradually stretching it into a longer, smaller diameter tube. I then cut thin slices of from the tube, and placed them onto a small thin sheet of white-ish clay. I cut off a section of this black roll, and rolled it smaller yet, and then filled in some of the gaps between larger circles with smaller circles. You can see the photos below.
I then rolled the sheet of clay to make it more uniform thickness. Unfortunately, this stretched the circles, making them larger than I wanted, but there was no turning back.
I then used a "cookie cutter" that is made for a specific pen tube size, and cut a piece from the sheet. I scuffed a brass tube, and then carefully rolled the piece onto the tube. It took a little massaging to smoosh the soft clay around to close the seam between the 2 ends. Once the clay seemed to be on the tube properly, I put it onto a simple fixture I rigged from some "T-Track" pieces and a piece of solid copper wire to hang the blank in the toaster oven. I didn't want the blank to sit on the wire rack in the oven, as I was concerned they would imprint on the soft clay.
I put the blank in the oven for about 20 minutes at 135C. I took it out, and let it cool a little while, then threw it on the lathe and gently turned it using a carbide negative rake pen tool.
I then sanded as per usual, and applied multiple coats of CA glue, polished with micro mesh, and called it a day.
Below is a link to the video where I first saw this technique. You can fast forward to the 3:08 mark to see this part of the video.
