CompuServe Thread

Hi Jim, I've been corresponding with Al Mitterling for a while via E-mail. I'm also a collector. I do think that Al can get you some very reasonably priced samples of various meteorites. In my opinion, he is very trustworthy. If you look into any Sky & Telescope magazine, you'll find 2 or 3 vendors of retail meteorites listed. My personal favorite is Robert Haag, who offers a Field Guide catalog for a nominal fee. He had 10,000 copies printed up a few years back and won't be printing any updated guides until his current supply dwindles somemore. Address: Robert Haag, Meteorites, PO Box 27527, Tucson, Az 85726. Another very professional vendor is Bethany Science led by Ron Farrell. He also deals retail in an assortment of common…and also very very rare exotics. He's often very pricy, but no other ready source is otherwise available for some things he stocks. Address: Bethany Science , Box 3762-A, new Haven, CT 06525. He furnishes updated catalogs for $2. My protocol for working etches onto my irons differ slightly from Al's: Start w/ 400 grit silicon carbide wet/dry sandpaper. Use several sheets before moving on to 600 grit. On the 600 grit, polish in all directions til all the scratches from the 400 are entirely gone. After the 600, polish with a buffing wheel using jewelers rouge. "Zam or Wham" buffing compound can be used to gain a higher polish. The better a polish, the more control you'll have developing the exquisite etch. After polishing, place specimen in 99% alcohol. I use methanol. Soak for at least 10 minutes. Prior to etching, the iron must be dry. This requires a dessicant or with careful heat. Usually, I opt for heat, in the interest of time. Heat your wife's oven to 200 degrees, then bake for 1 hour. After cooled down, you're ready to etch. Observe all of Al's caution about working with acid. Latex gloves are a must as is adequate ventilation. Don't forget eye protection! Cover all working surfaces with plastic and have absorbent paper towels readily at hand. Prepare an etching solution of 5% nitric acid in reagent grade methanol. Robert Haag uses 10%, but he's a pro. I benefit from the slower, better control. To etch the meteorite, hold it over a shallow bowel or glass brownie tray. Tilt the surface to 30 degrees from the horizontal or more vertically. Use a soft nylon brush and move the etching solution constantly over the entire face. Replenish the brush often with fresh etching solution. When the Widmanstatten pattern is it's brightest (this requires some experimentation and experience….unfortunately), rinse with distilled water, blot dry with paper towels, then dunk in 99% methanol to fully halt the etching process. When over-etched, the kamacite and taenite will become dull or grey. If this happens, you'll have to repolish and re-etch. You can't know how far you can etch until you've gone too far. After the alcohol dunking, rebake for an hour, then leave in a dessicant container with drierite for a couple of weeks. Finally, coat with a good grade of brushing laquer using a natural bristle brush. Clear sprays work adequately, but not as well. Lastly, store your beautifully etched meteorites in a dessication chamber. Here I just use a 2.5 gallon silicon-sealed commercial aquarium tank with a glass pane cover (from a frame store) and black electrician's tape overlapping seal. In the tank, a 1/2-3/4 inch layer of Drierite serves to keep moisture at bay. Moisture will in time otherwise crawl like a cancer under the lacquer along the etchlines, necessitating another painful re-etching job… I'm curious to learn where you obtained your initial specimens from. Al and I are interested in eventually developing a network of serious collectors…and neophytes!…in this forum… Hope some of the above will be useful to you… Hope to hear from you sometime. -Joseph