Tumbling Polymer Clay

I made some polymer clay beads, and when I did, I left fingerprints and nail marks all over them. I wanted to get all of these marks off and I was interested in seeing if I could make them look shinier. So I checked into sanding them to clean off all the marks.

A web search quickly showed that some people use a rock tumbler to do the sanding and buffing on polymer clay. They use sandpaper instead of grit because polymer clay is much softer than rock. For the same reason the time for tumbling is much shorter.

I thought I would try it. So here is the rock tumbler I got. It is a toy rock tumbler available at Michael's for about $20. (That is with a 40% off coupon.)



It has several advantages over professional tumblers besides price. It is small which is good for tumbling small amounts of beads because the tumbler should be about 3/4 full when it works. Also it is plastic which is nice because most real tumblers are rubber and the black rubber leaves black marks on polymer clay.

I went out and bought sandpaper in 3 grits, 400, 600 and 1500. I got it at Ace Hardware. I looked at Lowe's first but I couldn't find it there even after asking for help. The really fine sandpaper is often used for body work on cars so it should also be available at auto supply shops Walmart, and on line.


There should really be another grit between 600 and 1500 but I didn't find one at Ace, Walmart, or at Auto Zone. I found some on-line but I didn't get any yet.


I cut the 400 grit sandpaper into small pieces for tumbling. I loaded the container about 3/4 full with the beads and sandpaper and added water to cover and a drop of dish detergent.


Then I tumbled it for about 6 hours before I couldn't stand it and had to check on it. It is a good thing I did because all of the sandpaper curled up and formed into stacks so no sanding was going on.



You can see the rolled up pieces with stacks here.




So next I cut more 400 grid sandpaper up into confetti and put it back in along with a long piece lining the edges of the tank and added a piece on the top and bottom of the container. (It is important that the long strip of paper is arranged so the beads won't feed into the sandpaper when the tank turns.)


There is a picture of the confetti just below so you can see how big it is.





Some people glue their sandpaper together back to back to get grit on both sides and to discourage the curling. I haven't tried this yet and I may not ever. It sounds like a lot of work.

Then I put it back in and let it go for another 3 hours. (The recommended time for the first pass is really 24 hours.)


That seemed to work reasonably well. The strip stayed around the edge and the confetti was distributed throught the rocks although there was one big clump. The pieces on the top and the bottom curled into tubes with the grit on the inside so I left them off after that.


Then another 6 hours with 600 grit. (Till bed time)
And 8 with the 1500 grit (overnight)


An interesting thing about the sandpaper I am using is that it curls side to side across the sandpaper so long thin strips that run from top to bottom might work well for the squares.


After the sanding, it was time for buffing. The recommended cloth was white denim. It is clear from reading that getting the color right is more important than getting the fabric right. because color can rub off on your beads. I didn't have any white denim but I did have white flannel -- so I used white flannel.


I cut the fabric into squares roughly the size of the base of the tumbler so I could stack the fabric into the tumbler with beads in between the pieces. Many people buff with the fabric dry, but I was worried about things getting hot from the friction so I dampened my fabric. Then I stacked it up. When I was done stacking my beads and fabric squares I had a small air space at the top.


I let it run for a couple of hours and checked on it. All of the fabric was bunched up at the top of the container and the beads were all tumbling around in the middle.


So I lined the edge of the tumbler with a strip of the flannel and cut more strips so the container was full and set it off again. This seemed to work well. When I took the beads out several hours later they were still distributed between the flannel. Also nothing seemed in the least bit warm so trying to buff with the fabric dry is probably safe.


Overall I think the whole process worked pretty well. The beads look better and feel much smoother. There are still a few fingerprint marks that I can see from looking for them but I'm not sure other would notice them.


Next time I do this I will probably start with 200 grit sandpaper. When I was looking up the buffing I ran across advice that beginners need to start with 200. Also leaving at least the first pass longer seems to be in order. That is to get the marks all off.


I may still finish the beads with Future floor wax. That is one of the recommended ways for finishing and I think I have some on hand from last time I did this.