Wednesday, October 26, 2005

Crystal and Rock Polishing

I don't remeber where I found this, nor who Uncle Ross is.


Uncle Ross Wenger, the fellow who helped raise my father became my adopted grandfather, was a big time rock hound, surveyor, and miner, but his favorite was crystals. Not only was he the one to get me into crystals, he used to take me into some of the most incredible caves in the world with walls just made of crystals. He used to earn a little extra money by slicing up and polishing some of his rock finds, particularly petrified wood. He shared some of his skills with me, but I never achieved his speed in quickly achieving the same results. For my own crystals, I pick them out liking the way they feel, so let them be. Once in a while I will inherit a poor crystal that has been abused by being banged around. I do sometimes shape these and polish other stones for myself and friends just because I like the look and feel also!

Anyway, the first thing you need to do make a commitment to spend the time and money to do the job right. First, do just like the jewelry stores and all but soak your stone in thin super glue if there are any visible breaks. Otherwise your abrasives will gather in the cracks and make for a not very attractive result. If there is a bad end or chipped off point, you should find someone with a diamond saw and have that part cut flat. It just takes far too long and is too expensive in terms of abrasives to try and sand big areas flat. Trying to grind away with the wrong tool will almost always break your piece. You just have to have the right tool! Next, you have to buy a succession of ever finer abrasives including the right polish to be able to finish with a highly polished surface.

The first abrasives are the ones used to shape the stone. If it is already shaped, then you can skip this step. To do the shaping my grandfather used a diamond saw and a diamond flat table. His were electric but you can do the same thing by hand. Way back then, diamond based tools were terribly expensive. Today you can go to Harbor Freight and buy a three piece diamond sharpening stone set (Fine, medium & coarse) for $3 this month on sale or about $12 normally. Although you could do the same thing with wet sandpaper glued to a very flat surface such as steel or glass, these diamond surfaces will do a much faster job. You also can buy a Dremel or similar 1/8" shaft rotary tool and pick up from that same catalog order firm a real nice set of diamond points (also about $12) known as burrs for making shapes, cutting in letters, etc. I found that these stones and burrs are also available from Post tool at nice discount prices. Regular retail prices can quickly push you over $100 for just the shaping stones, so take your time and do some shopping.

Once the shape is good and the major scratches worked out with the diamond tools your next move for polishing crystals is to use "sandpaper" glued to glass to take care of all the rest of the easily visible scratches. (For rounded stones you can just hold the paper or glue it to a sponge.) For crystals you need a perfectly flat surface if you do not want to mess up the sides, so a piece of 1/4" tempered glass that is about 14" square is ideal. I use a 3M Scotch photo mount adhesive (about $8 a can) to stick the special sandpaper to the glass as it works quickly and will not be bothered by the water you need to constantly use. Actually it is not called sandpaper, but instead known as wet-dry emery cloth that is a dark green or almost black. You can get the coarser grits at a hardware store but have to go to an auto finishing or supply store to get the finer grits. Your fine diamond stone should have been about 200 grit meaning two hundred diamond particles per linear inch. You need to move upward from there buying 400 grit, 800 grit and at least 1000 grit emery cloth. I actually go to some 1800 or 2000 grit as it makes the polishing go much faster. (Sometimes the auto people call this grade of emery cloth as that stuff used for color sanding which will let you invisibly repair chips on solid color paint). While at the auto paint store you also should get your professional grade polish used to put the final high gloss polish on the piece. I have had very good luck with Ditzler brand extra fine rubbing compound that is used to final polish new paint. Caution! The every day kind of polishes and rougher grit polishes are far too rough to do a good job!

Now to actually do it, start with practicing on other rocks before you tackle your good stones. Use plenty of water on both the hand stones and powered diamond burrs. Be careful mixing water and any electric power tool.. I use a long flexible shaft on my rotary tool to make sure there is no problem. The water is critical as it keeps things cool and takes away the buildup of debris so your stones and burrs keep cutting cleanly and quickly. Do your rough shaping with the most coarse stones then work your way to the most fine. Take out all the major imperfections and scratches before moving on to the emery cloth. For crystals I use the glass with plenty of water (I have a little squeeze plastic mustard bottle and work in a large pizza pan!) Start with a grit about twice as fine as your last diamond tool and then work until all the deeper scratches are gone. Shift to the next finer emery cloth.. (Cheat and glue one grade on each side of your piece of glass. I have two pieces of glass and use four weights of emery cloth and rarely have to change paper as they do not wear much at all) Continue shifting until you have finished with the finest paper. Then shift to using the polish on a soft cotton flannel rag or lamb's wool buffing pad. It takes me about 4-5 hours to polish up a three inch point, but the result can be stunning.

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