Vibratory Tumbler

[jcornell]

Noob question here.

 

I got a vibratory tumbler for Christmas - the smaller type that is usually used to clean brass casings for reloaders.

 

I've got it loaded with crushed walnut shells and a bit of brass polish and I'm vibrating 3" rings that I've made (Christmas ornaments) along with some split crosses.

 

How long do I let it tumble to knock off all the scale?  I reckoned that this would be safer than the wire brush on the bench grinder (which works well, but scares me).

 

As a practical aside, don't leave the bag of walnut shells outside - a local squirrel attacked the bag, scattering it all over my driveway.  He must have figured that there was a nut in there somewhere!

 

Would I be better off using another abrasive - say glass for sandblasting or something else?

[BIGGUNDOCTOR]

Forever..

Glass beads won't work either-too heavy,and they don't allow the part to move.

We use a plastic media with an abrasive in it at work.

Wire brush the parts while they are hot to knock the scale off when in the forge.

[njanvilman]

Why not a mix of some glass beads and nut shells?  I find the process of experimentation to find what works very satisfying.

[DSW]

Different medias clean at different rates. When I used to work at the dive shop  we used to have a number of different medias for both for cleaning cylinders, as well as various reg or compressor parts. Some like glass beads or walnut shells were very "mild" while others like the ceramic chips were more middle range. We used to use alum oxide chips to remove heavy rust and in some cases we tumble those cylinders for almost a week, but using that for more than 15 minutes in an alum cylinder would destroy it.

 

Watch how aggressive the media is in plastic tumblers. Many mild abrasives won't seriously effect the plastic, but more aggressive ones may wear the plastic as fast as the  thing you want to clean.

 

A friend of mine cleans plasma cut parts in an old cement mixer filled with steel scraps and sand. The old plasma cut scraps knock off the dross easily and the sand polishes the steel to almost a mirror finish and can kill the crisp edges if you aren't careful.

[SmoothBore]

In a vibratory bowl, the KISS rule applies in nearly all situations.

 

There's a wide variety of Media available, targeted for particular applications.

 

It sounds like the parts you're working with, require fairly agressive abrasion.

 

You won't get that from Nut Shells.

 

 

I'd start off with dry "Pea" gravel ( cinders ) that's been washed in a Colander, ... to eliminate the "fine" sand and dirt.

 

Within an hour, you'll know if that's working.

 

When the parts are sufficently clean, ... add soapy water to the bowl, ( "Simple Green" works great ) to see if that won't get you the "polish" you want.

 

Again, an hour or 2 should get results.

 

 

The Nut Shells are for polishing "tarnish" from metal that's already free of scale, ... or paint.

 

Crushed Corn Cobs work well with "Jewlers Rouge", ... for polishing softer metals.

 

 

Steel Shot will put a nice patina on steel parts,  ... and, if you can find them, ... the little Cast Iron "Stars" really work well, to remove burrs and scale.

 

You can also buy a wide variety of "Media", in various shapes and Grits, ... but I'd try the simple, readily available options first.

 

 

Sometimes you have to experiment with speeds and Media, to find that which works best in a particular situation.

 

 

 

 

.

[Smithy.Travis]

What about a load of ball bearings? Would those work or would they be too heavy?

[BIGGUNDOCTOR]

Too heavy. The problem with these case tumblers is that they have the wrong action for heavy media. They bare designed to remove tarnish from shell casings. I have tried bead, and it doesn't do anything. A true rotary tumbler like the ones for rocks would work.

[RGraff]

I used ceramic media of varying shapes (depending on the geometry of the part being tumbled).  Worked well on steel scale. 

 

Not advocating this particular vendor but the link illustrates what we used.

 

http://www.vibrafinish.com/vibratory-media-ceramic-sp.html

[swedefiddle]

Slugs from a punch press work great in an old cement mixer. So does a few shovels of 3/4"minus gravel.

There is no wrong, just some work better than another. Depending on what you are doing.