Tumbler Troubles

Tumbler Troubles

As some of my faithful readers may remember from previous blogs, I've been an active devotee of the hobby of metal detecting for quite a number of years. I've used a half-dozen machines of various makes and models in the course of this hobby, the latest of which I purchased last year. The aim of the hobby is, of course, to acquire “treasures” from the ground. As you might imagine, the gold rings, gold coins, silver dollars, jewelry and other goodies are the most sought after. But the normal acquisitions that the ground yields up to the metal detectorist are usually common, everyday coins – cents, nickels, dimes and quarters – or rarely a half dollar. Occasionally a dollar coin is uncovered or some other rarity, but the vast majority of finds are quite simply pocket change.

What you have to understand about coins lost in the ground is this: they change color and get tarnished during their sojourn in the soil. I'm not sure of the chemistry, but the various metals in modern coinage react to the soil by darkening and tarnishing. So the coins you bring home at the end of your day digging them out of the ground will eventually need cleaning before any even semi-observant store will accept them. Or the banks. Or anyone.

I haven't cleaned any of my finds for a number of years. I've just been tossing them into a big jug in the basement and figuring I'd “get around” to cleaning them “one day”.

So the jug of dirty money sat in the basement.

Upstairs, in the extra bedroom we use for our library/computer room/file storage room we have two big jars which we also use for coins. They were originally the depository of pretzel rods. Now they hold pocket change. One is for cents only, the other has mixed nickels, dimes and quarters. There's LOTS of coins in them, about forty pounds worth in each one nowadays.

I've been looking at them for some time now, wondering what I was going to do with that money when I cashed it in. I wanted it to be used for something special, not just household expenses. The last time we had an accumulation of a magnitude near this size we bought a nice digital camera with the proceeds. But we had no need for a new camera at the moment, so what would we do with it?

As my faithful readers may also remember, my wife and I got into a new hobby last year – geocaching. That's where you get the coordinates of a hidden “treasure” on the Internet and, using a GPS receiver, go and find the target. When found, you sign a logbook, exchange small tokens if you like, and log the find on the Internet. We'd been using one of the more inexpensive GPS receivers last year and had talked a bit about getting a better one.

Aha! A reason to break the two “piggy banks”! A new GPS!

But, if I was going to do that, why not add the dug coins from the basement stash to the two big jars upstairs?

All I had to do was clean the dirty ones.

As you may or may not know, there are several ways to clean dirty coins. I've tried most of them. The easiest way is with a rock tumbler.

Let me explain.

A rock tumbler is a machine who's original purpose is to tumble semi-precious rocks in and, by tumbling with various grades of grit, smooth and polish those rocks until they became like gems and could be used to make jewelry of various sorts. You've probably seen them in rock shops or souvenir stands in bins with hundreds of smooth, colorful pieces of various minerals.

The rotary rock tumbler (the kind I have) is quite simple. It's just a soft rubber barrel into which you load whatever rocks you want to tumble to smooth and polish along with some grit. You seal the barrel and place it in a metal box where a motor turns the barrel. The load of rocks and grit in the barrel tumble against themselves and, by doing so, wear themselves smooth and rounded and, depending on the grit, highly polished.

The rock tumbler is also a dandy way to clean dirty coins. I have an old rotary tumbler which I purchased at a garage sale many, many years ago. It's given good service, but was definitely showing the signs of age. I'd taken the cover off the drive machinery (it didn't fit well anymore and rubbed the barrel) and had to doctor up the drive shaft (that turns the barrel) so it would grip the barrel better. Along with other tweaks. The barrel itself was old and the rubber was showing a lot of wear and dryness.

Last Saturday I sat down and sorted through the “treasures” in the basement jug. I separated the pennies from the clad coins and those from the other “stuff” in the jug. I ended up with two piles of dirty coins. I loaded up the rubber barrel from my tumbler with the pile of clad coins along with some sand, some aquarium gravel, some water and a dash of dish soap. I sealed the lid on the barrel and started it tumbling. I had to wrap some masking tape on the drive shaft to give it some “bite” so it would turn the barrel. It was running fine.

I left it running for three days which is what I usually did for a load of coins.

They came out fine. I rinsed the gravel, sand and slurry off the cleaned coins and let them air dry. They were plenty clean enough to spend, so I carted them upstairs and dumped them into the “silver” jug.

I then loaded up the cents into the barrel. You don't want to mix the cents with the clad coins as your result will all look coppery, even the clad ones. I started them tumbling three days ago.

They were doing fine yesterday afternoon which was the last time I checked them.

But as I descended the basement steps this morning, planning on emptying the barrel and rinsing the cleaned cents, I subconsciously noted a change in the sound from the workshop where the tumbler was running. Instead of the light grinding and grumbling a loaded barrel made when it was rotating, I just heard a humming. The humming of a rock tumbler motor without a load.

I grit my teeth, took a deep breath, walked into the workshop and turned on the light.

Sometime between yesterday afternoon and this morning, disaster had occurred on my workbench. One of two things had to have happened. The first possibility was that the idler shaft that kept the barrel square while the drive shaft turned it, had slipped out of it's bearings and dumped the barrel, thus knocking off the lid and dumping the contents on the bench top. The other possibility is that the barrel itself had succumbed to dry rot and had popped the lid off itself, dumping the contents onto the idler shaft and knocking it off.

Whatever the mechanism of the failure, the gray-black slurry that was in the barrel was suddenly ejected onto the motor's fan which, in turn, then splashed the glop onto the walls and everything within six feet of the motor. It was a mess, with gray splatter seemingly everywhere, dumped cents all over the machine with the dark slurry hardening into a stone-like mass over everything.

And the coins weren't even clean! They needed another day or so tumbling.

So...

I cleaned up the cents as well as possible, rinsing the gravel, sand and slurry off them, and put them on some paper towels to dry.

Tomorrow I'll start cleaning the workshop. Or else I may just paint the rest of the room in polka dots to match the slurry splatter that's there already.

I'll have to think about that.

In the meantime I've given the wrecked tumbler the old heave ho and have ordered a new one from a company on the Internet. It should be here later this week.

Then I can finish tumbling my pennies.

And what did I learn from this coin catastrophe?

I guess you could say I've got a cents about needing some change in my life.

Yeah, that one hurt...