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Contour Polishing Petrified Wood

So you have a rough piece of petrified wood — a nice full round. What do you do? Step one is to get out all the big steps and divots as quickly as possible. Put a diamond blade on your angle grinder, a respirator over your mouth and nose and drag the diamond blade over the problem areas. This is a dry operation and moves lot of material fast. To finish shaping, use a Barranca or similar wet contour grinder with a coarse diamond wheel. After shaping, the fresh surface may want to peel and crack, so it’s necessary to fill the fractures to hold it together. Use 330 two part epoxy thinned down with acetone till the mixture is thin and runny and clear as water. Use a teaspoon to carefully drip the epoxy into the wider cracks and then use a toothpick to fill those cracks the rest of the way and to fill in tiny cracks. This gets the cracks filled without trapping air iin the bottom. After the whole piece is treated, let it sit in the sun for days to cure. Now you can proceed with the usual grinding and polishing steps with the Barranca.

via The Pegmatite 6/08 and Breccia 10/04 (John Dahnke.)