Dolomite, thanks for the tips. Rustyshakelford, thanks for the offer to use the correct stuff, it was very kind but I went ahead and just gave it a try using stuff I had around the house. My thought was if it didn't work well enough I might take you up on your offer. It turned out well enough for me at this stage. I just trimmed and used a round file to get the shape. Wet the area a little and then used the barrel of a pen to burnish it until it was very smooth and hard. Then I used one of my wife's brown craft markers.
I'm going to run it this way for a while to see if the edge stays smooth and hard. Rustyshakelford, if it doesn't I'll give you a shout.
Before shot showing the area around the grip that was in the way to get a good grip.
After shot
Shot of the inside