Tumbling Questions

[Paul Alciatore]

I got one of those small tumbling machines from HF and it seems to work fairly well. I also bought a box of crushed walnut shell media for it. So far I have used it to clean up some old nuts and screws I have.

I also tried to finish some small aluminum parts with fairly good results. After with my success with the nuts and screws, I was initially disappointed with the aluminum parts. After several days of tumbling in the walnut shells they were only mildly improved so I added a bunch of nuts to the drum and they seemed to turn the trick. Apparently you need something in addition to the walnut shells to actually finish the aluminum parts. I thought of some abrasive like sand but did not want to use anything too coarse as it may have too drastic of an effect.

On another shopping trip I noticed that they do sell abrasive in small packets apparently to be added to the walnut shells. This sounds logical and there were four grades of abrasive in the box: I got one. But no instructions. So what I am wondering is exactly how much abrasive should I add to the shells for different kinds of parts? Steel, aluminum, brass, plastic? Can anybody provide guidance here or do I just have to experiment?

[Frank46]

I use walnut shells in my cartridge case cleaner. It's a vibratory type. After the walnut shells I dump it out to be reused and fill with corn chips. Definitely not the ones you eat. Brings brass to a high luster shine. Check any good welding shop and get their reccomendations. I would think an abrasive is the last thing you'd want to put in your tumbler. You are wanting to polish and deburr those parts. Sometimes on really crudded up brass I use some Bon Ami which is nothing more than ordinary scouring powder like you would use on sinks. Oh yeah the corn chips are nothing more than ground up corn cob. Hope this helps. Frank

[J Tiers]

I had some toolbox (case) hardware to clean up, had some rust/corrosion, hazy finish, etc. Have an old legitimate tumbler, about 8" diameter, not the tiny HF unit. The hardware was corners, edge straps, hinges, and handle plates. Very irregular shapes, with inside corners, etc.

Walnut shells did exactly nothing useful. Slight polishing of the rust.

Walnut shells with some abrasive did slightly more of nothing.

Some mixed old hardware did more work, but not what I wanted.

I finally went out to the shed and got some sand. That, with water, did exactly what I wanted.

A final run with walnut shells and a little oil polished up and coated them. The process cleaned up the surfaces, and gave a polish that should be a good base for replating.

[Grind Hard]

You actually need an abrasive media to remove rust and scale. Shell and Cob are great for final cleanup.

Sand works great with water, as was mentioned. I ran out of abrasive-stone media so I used a handful of gravel off the driveway, once. Worked quite well.

With aluminum and thin steel parts you will want to watch your loading, as tumbling can damage edges. For those, use a medium-fine abrasive and watch your cycle time.

[Paul Alciatore]

Hummm. I feel a wider internet search coming on.

[moe1942]

Steel shot..number 8...

[amatts]

I got one of those small tumbling machines from HF and it seems to work fairly well. I also bought a box of crushed walnut shell media for it. So far I have used it to clean up some old nuts and screws I have.

I also tried to finish some small aluminum parts with fairly good results. After with my success with the nuts and screws, I was initially disappointed with the aluminum parts. After several days of tumbling in the walnut shells they were only mildly improved so I added a bunch of nuts to the drum and they seemed to turn the trick. Apparently you need something in addition to the walnut shells to actually finish the aluminum parts. I thought of some abrasive like sand but did not want to use anything too coarse as it may have too drastic of an effect.

On another shopping trip I noticed that they do sell abrasive in small packets apparently to be added to the walnut shells. This sounds logical and there were four grades of abrasive in the box: I got one. But no instructions. So what I am wondering is exactly how much abrasive should I add to the shells for different kinds of parts? Steel, aluminum, brass, plastic? Can anybody provide guidance here or do I just have to experiment?

Several years ago,I invested in a 5# raytheon(US Made) vibratory finish mill. Try a local jewelers supply for media choices.I use plastic,steel shot,and ceramic media(HF) with good results on ferrous and non ferrous material.The HF triangular media works the best on rust removal,w/o alter the shapes or threads.

[J Tiers]

The HF triangular media works the best on rust removal,w/o alter the shapes or threads.

That stuff is so BIG that it seems virtually useless on many things. The triangles are well over a half inch in size, IIRC. The case hardware I referred to earlier was only 2x or 3x larger than those huge triangles.

I would expect them to be unable to reach into any but the coarsest threads or details, threads for 5" dia bolts, for example. Anything smaller looks like it would be battered into pulp in a tumbler. A good amount of liquid might prevent the worst of the battering.

[Grind Hard]

They make round media, square media, triangle media. Big, small, huge, tiny. There is a "right" size for every task.

1/2" triangle media is great for larger parts or heavy grinding.

In your application Jtiers I would have used a round cylinder shape 1/8 by 1/16th. Rice-media I call it.

[J Tiers]

They make round media, square media, triangle media. Big, small, huge, tiny. There is a "right" size for every task.

1/2" triangle media is great for larger parts or heavy grinding.

In your application Jtiers I would have used a round cylinder shape 1/8 by 1/16th. Rice-media I call it.

Very good.

But the other poster described HF (Harbor frieght) media and the only ones they ever have in stock are the huge ones.

In fact, looking at their website, they only list two types in "tumbler media" ...... big triangles, and "spark plug media", which appears to be grit. But they do also have walnut shell media (which they list as "blast media"). They also list a couple types of "resin" (plastic) shapes, listed for for vibratory cleaners.... if you look harder, they have rock polishing abrasive.

I don't suppose they even know what the stuff is used for...... or they would offer different options, and list appropriate stuff in each category. Their tumbler is tiny, and they list it for "rock polishing".