Shopsmith Forums

I think I'm going to give it a try.

Tom - It's a concrete mixer - I need to throw some new slabs.

Mike - First I'll remove the agitation fins (thanks). They are just bolted in place and I'll temporarily plug the bolt holes.

Next I'll run 2 test batches with bits of scrap steel & scrap aluminium, and I'll run each of these tests with a coarse concrete sand, and a fine plaster sand.

Red - I like our little committee members - they keep our dogs fit and they don't steal. Besides which, the new babies are just way too cute and very entertaining. Also, I don't want to wash gore out of the mixer

Stay tuned for pictures & results in a couple of days time.

The only thing I ever tumbled besides a few stones was spring steel stays that held the cover of an A.B. Dick mimeograph machine up off of the inky drum. They were sewn into the top of the cover. I used to (about 46 years ago) cut the bands to length and with round ends using a punch press then feed them through a triple roller press to put a curve in them and then tumble them to remove any burrs. The tumbler was about 4 or 5 feet long and maybe 30 inches in diameter and hex shaped. The cover was one of the sides bolted in place. I tumbled them in a "mess" of scraps from the machine shop. Nuts, bolts, and about anything steel. Old files broken into about 2" lengths worked great. The steel was kind of oily off of the roll and I would toss in about 3 gallons (dipped with a big old gallon can) of sawdust into the whole "mess". I would let it run a few hours then take them out and take them to a bunch of ladies upstairs that wiped them down and inserted them into the covers (thousands of covers per run).

I have a friend who cleans clock parts (including some very high grade delicate parts) in a rock tumbler with stainless steel media and cleaning solution. The results are remarkable and I am halfway convinced to dump my ultrasonic tank.

The only problem is you would need a lot of the media for a cement mixer, I believe he said the stuff is currently about $30 a pound. The tumbler is plastic and has a lid that is water tight. I would be concerned that the parts may be damaged when the hit the sides of your cement mixer.

I agree with Heath, try it on something expendable and post pictures.

Troy

Depending on the size of the parts, what if you took one of those 5 gallon plastic buckets with sealing top, put the parts and abrasives in the bucket, and tumbled that in the mixer? Would the bucket self-destruct or would it be resilient enough to protect the aluminum parts from the mixer's fins?

This is the mixer


I selected a few actual ShopSmith items for the test. I only used items that I won't be upset about damaging.

Before



The poor mixer was not designed for continuous use, and I had to switch it off every half hour for fear of overheating.

Items Tumbling


And YES, I did leave the mixer fins in place. I kept an ear open for knocking sounds that would indicate possible ding damage, but they were few and only slight. I reckon the sand cushioned the impacts.

See Next .

In total, I tumbled these items for just over two hours.

After



On close personal inspection, I can see that the parts are a lot cleaner and that dirt and Al Oxide has been cleaned off. I see NO polishing effect starting.

But
This was an unsuccessful experiment. Maybe several more hours would do the job, but I don't think it is worth pursuing any further.

We live and learn.
.

No experiment is unsuccessful! You may not achieve a certain desired outcome, but the real point of an experiment is to "see what happens." Mission accomplished.

I'm glad you did it and appreciate you sharing!

Certainly not a failure. True the parts aren't polished, but you have found a relatively painless way to remove the dirt and Al oxide. That is at least half the battle.

Troy

It would take several days with a tumbling process to get a bright polished surface. I've got a small 100% duty cycle tumbler at work that I'll try out on a couple of the aluminum parts on 'pinkie'.