When I need to sand the inside bottom of a vase I like to use a sanding stick made out of styrofoam. The stuff they sell at Home Depot, etc to insulate foundations. They call it “Rigid Foam Board Insulation”. I use the 2″ thick stuff.
Why styrofoam rather than a wooden dowel? It hurts a lot less if the lathe rips the sanding stick out of my hands and it hits me!
I have found that attaching a small piece of Red Siasoft Sandpaper works best. The tough red side lasts a long time. The soft yellow foam side helps it conform to the round shape in the bottom of my vases.
I like sticks that are roughly 10″ long and 2″ diameter with different shapes on each end. See photos.
I use the stick with the lathe running. I use the pointy end to sand the center in the very bottom of a vase. I use the slightly rounded end to sand the area in the bottom of the vase where the side walls transition into the bottom.
I have 3 sticks. One for each grit. 120, 180 and 220.
Note: I use a Ring Tool to CUT the bottom as clean as possible before sanding.
Make Your Own
b. Make it sort of round (rough it out) with a hand held hacksaw blade or a knife with a long blade. Use what ever you have.
c. Sand it round with sand paper. I use a big belt sander. The belt tends to grab the styrofoam and rip it out of your hands. Thus, hand sanding would be safer.
d. Sand a bullet shape on one end and a slightly rounded shape on the other end. See photo #2.
e. Attach Red Siasoft Sandpaper (or what ever floats your boat) to each end with masking tape. See photo #3.
Here are some photos showing me sanding the inside of a vase.
The next photo shows the inside bottom of the vase after sanding. Nice and clean. Ready for a clear finish.