Friday, March 13, 2015

Lapidary Lessons

You get taught a lot in lapidary class. By the end you will have operated a saw, chosen stones and templates, worked a series of grinders and polishers, been shown how to clean up after yourself, and produced two reasonable cabochons for... whatever.

There's still a lot the class doesn't cover, however. If you keep going with it, asking questions, making mistakes and learning from them, you will begin to find out what those things are. Perhaps the following will help you on your way.

It took you a while to produce your first cab. The second was a little faster,. You will continue to speed up as you become more comfortable with the machines and your coordination and skills improve. Then you will get slower. The day you decide you can produce 4-5 cabs is the day you start to learn why you can't. And why you shouldn't.

Murphy is alive and thriving in the lapidary room. And with practice, your standards of what you should produce will rise, unmet, at least for a while.

Let's start with the stones. Chances are you had pretty ho-hum ones to practice on. Why let you ruin the good stuff first thing? So while infatuated with your early success, you head off and acquire something fancier. It will, guaranteed, be harder to work with. The prettiest spot on the rock slab will be the place where it cracks, chips, and/or is soft enough to gouge with an eye blink. (Hey, I swear that's all it took!)

It's easy and convenient for source material to browse through the donations box at our club, where people who have a leftover chunk of rock donate it for the club to sell, for $.50 or a buck, depending mostly on size. You can't believe some of the things that get donated! One has great colors, the next a druzy, the next pockets of agate or some wonderful new mineral or who knows what? So you donate your buck and start working the rock, and find out just why somebody else tossed it. But just to keep you on your toes, the next donation will be a real gem, keeping your hopes high.

Personally I love to browse eBay for rock slabs. If browsing were all I did, my Master Card balance would be much lower. But I do wind up with some great specimens, and get a lot of questions from others in the club about what and where on my stones. Apparently I'm the only one who knows about eBay. So here's how it works, rubes. Name a rock, say agate or jasper or whatever. Add "slab" to your search. EBay then offers you a list. Select your choice under "in rocks and minerals". Browse. When you see something you particularly like for color, quality, etc., click on "see sellers other items" for other ideas, and the possibility for shipping discounts on multiple orders. And off you go.

The next independent working lesson is that you need to be adaptable. Whatever Plan A was for your rock, you better be able to switch to Plan B, C, or on a particularly bad day, Plan D.

Starting with the saw, somebody else is likely using the particular one you want. Or it needs Gem Lube, or wasn't cleaned. Or some idiot bent the blade and the replacement is on order. If you are lucky, everything works or you have other projects in process you can switch to. Even in the best of shape, it vibrates, and it can vibrate your rock to pieces, like the black turritella fossil chunk. You also find out, just when you smugly thought you had a soft touch with the saw, when you ease off for a second on your pressure on the piece you are cutting you have actually been pushing it a bit sideways rather than straight ahead, and with luck have stopped short of being the one to bend the blade.

The saw is noisy. So are the grinders and polishers. Nobody bothered to mention earplugs, but go get some before your next session. One could assume nobody else cares about their remaining hearing, but that's not an excuse. They do not reach the decibel level of that rock concert back when - or not so when - but at this age every bit matters.

They show you the safety glasses in class, but don't bother to let you know that all the aerosolized oils and rock dust coat your glasses, so you not only need to clean them before sawing and grinding to see just where you are cutting and when to stop, but afterwards as well so you can see, say, to drive home. And while we are on that subject, you will be coughing the sprays back out while you sit near the saws, and even after washing it all off your hands, arms, etc., lotion is a must to repair skin and nails.

Once you are ready for grinding, there is again the competition for the machines. If you see the ones you want free up but choose to take another 30 seconds in the conversation you've been having, chances are excellent there will be another 30 minutes to talk because you missed the opening. With three sets of polishers, you'd think waits would ease, but the person who cleaned it last time likely put it back together so that the air hose (which spits water onto the belt so it can do a proper job) is in the perfect spot to get cut by that same belt. Leaky hoses are not efficient at pushing air to the desired location, and your machine is useless. Waiting till late afternoon is an alternative to long lines, but while the room is supposed to be open until 4:00, low occupancy results in pressure to close early, and there are fewer people present who know how to fix whatever happened to whichever machine it is that you need next.

With all the various messes you make or otherwise need to deal with, it helps to bring a variety of rag towels from home. The oils go all over during the sawing parts of the project, and you don't want them messing up stuff later, so that towel should stay separate from the ones that mop up water, and the cerium oxide towel should not mix with the tin oxide towel because you want your cab clean between the two steps. They don't have to be big towels, but plan on laundry. The clean oil goes in the machine a pale orange color but spreads all over everything in a medium blue. At least it's easy to tell which towel is full of the gem lube. And even though you wipe off your hands thoroughly before riding the scooter to the hand- and rock-washing sink, the handlebars get gooey with the stuff. And do assume  the cleanest towels will be full of lint or critter hair: deal with it.

Let's assume that everything goes well. Machines are cleaned, maintained, available. Your skills have grown, your rock stayed together. Surprises still await. The cab you get is never the same as the rock you started with. Occasionally it is the result of "operator error". A gouge or scratch "appears" (magically) and has to be ground away and smoothed over, leaving a smaller, perhaps differently shaped cab than intended. Colors and content change as you take off layers of rock to cut and shape it. Old bits of pattern disappear, layers bend and new substances, even geodes emerge. Polishing intensifies colors, some of which can be seen ahead of time by wetting  the rock. A couple of cabs revealed and then hid hematite, others surprised me with fools gold, some of which disappeared again before the stone was finished.

Whatever you are working on, three other people will have 4 better opinions of what you should or could have done with it. Working with mahogany obsidian today, one fellow thought I should stop and split it into two thinner slabs, leaving me two cabs instead of just one. He didn't take two things into consideration, however. Thicker obsidian is easier to work with, sturdier, less likely to chip and shatter, more forgiving when it does because it has additional material for a workaround. And second, we have no saw capable of splitting one slab into two thinner ones as he was suggesting. I'd wind up with zero if I tried on what I'll call the slabbing saw, the one which slices a chunk of rock into slabs. My rock would have to be glued to a flat wooden surface and I'd neither get the perfect angle for even thickness, nor the thinner slice unglued from the wood. The way the stuff chips, I would anticipate a pile of glass shards. Perhaps a laser cutter? Anybody?

Anyway, I still have most of the original chunk left to slab, and can adjust thickness as desired for the next times.

On the other hand, sharing ideas increases your stockpile of both ideas and skills, making you more flexible and productive. Lapidary is like working on computers: there are always other ways to get something accomplished. I can click-and-drag, copy-paste, Command c & command v to move data to a second location on my laptop. I have options of when and how to fix a problem in a stone, or even change stones to accomplish what I'm after. My cab can be drilled, wrapped, set in a bezel, glued onto a bolo backing, or many other options for display or use.

We started out using templates. I didn't like the ones supplied and designed my own. Then I started looking at smaller rocks and seeing what the rock had in mind. None were symmetrical, patterns went where they would. So now my cabs do too. And since they are larger than the templates, they take a lot more work. Part is the obvious: bigger stone takes longer grinding. Another part is the big challenge of keeping a rounded surface on a large flat rock. We start with a 90 degree edge, then carve off a 45 degree angle leaving about an eighth inch still vertical. Then we grind that to round. It has to be a very long slow slope to have anything round in the middle of a bigger stone. That's what takes the time.

You can want it flat, like it flat, adore it flat. The problem is in the polishing. If you want an unscratched shiny middle to your stone, the machines can't do it on a  big flat one. The grinders and polishers are flat belts across revolving wheels. Any part of the rock that sticks up roundly can be smoothed off. The wheel misses where it is flat. Worse, when big enough, it is wider than the belt, and the edges of the belt touching the rock leave a gouge. Actually, lots of gouges. Every-which-way gouges. Any time they touch.

And there's nothing around to polish them off. After a point, rather than improving your polishing job, all you get are more gouges and scratches.  Still worse, with all the extra work and frustration, it becomes easier to slip a little bit and put gouges into the rest of the rock. Yes, the very one you've now been putting hours of work into. This is possible no matter how fine the belt is you are working with, even the final polishing belts that seem to be nothing more than layers of cloth stretched over a wheel with a polishing agent. They too can scratch. Just when you've relaxed thinking the belt is harmless.

It's mind boggling.

I'm getting better. The center scratches are getting teensier, the flats are smaller, the accidents fewer. I'm becoming a perfectionist, finally knowing why I can't put out 4-5 cabs per day. And almost meeting my own standards. I'm sure there will be more lessons ahead the instructor missed.

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