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Post by chris1956 on Jul 19, 2023 17:26:56 GMT -5
I started working on this one this afternoon and thought for sure it was destined for the driveway. I was surprised after I started grinding away and found this pattern. What was exposed was the bottom of the coral which usually doesn't present the best but looks good for this shape. It has one bad spot and a crack in the middle but I was afraid to grind away any more because the fossil was almost paper thin at the top and I really liked the shape and size. I flattened the bottom so it will stand up on a flat surface. It is about 3-1/2 inches tall. The second pic is a side view.   |
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khara
fully equipped rock polisher
Member since September 2022
Posts: 1,979
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Post by khara on Jul 19, 2023 18:01:52 GMT -5
That’s cool. I didn’t know that Petoskey stones could be just thin layers on or in a host rock. Do you use belts for sanding and polishing something this big?
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Post by chris1956 on Jul 19, 2023 18:29:30 GMT -5
It is only thin towards the top of the stone. If you look at the side view towards the bottom, you can see that the Petoskey stone fossil (darker) is on the left and limestone (lighter) is on the right. I am assuming that the top of the coral, for whatever reason, didn't get fossilized but the bottom portion of the coral did. So I would think that sediment piled up on the thin layer of coral that did get fossilized. But I could be wrong, just my guess.
I polished this on two cabbers. I have my 80 and 220 8-inch metal wheels on a Covington unit. The wheels are only 1.5 inches wide so it did take some effort to grind down the length of the stone and make sure I didn't have any uneven areas when I moved along the length. Then I switched to a Kingsley North Cabber 8 which has two inch wide wheels 280 through 50,000 grit. That unit has enough room with the width of the wheels and spacing in between wheels that polishing wasn't too hard. I like doing a final polish on 14000 and 50000 wheels rather than buffing with polish because the small voids in the Petoskey stones tend to collect the polish.
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Post by jasoninsd on Jul 20, 2023 0:27:26 GMT -5
First, I gotta say that looks AMAZING!! I love the pattern capture in that one! Great job on figuring that one out! Second...that shape (which is awesome!!) totally reminds me of those blow-up punching bags!  |
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Post by chris1956 on Jul 20, 2023 13:23:09 GMT -5
First, I gotta say that looks AMAZING!! I love the pattern capture in that one! Great job on figuring that one out! Second...that shape (which is awesome!!) totally reminds me of those blow-up punching bags! Now, if I could just get the rock to bounce back up after it is knocked down, I would really have something. LOL |
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Post by jasoninsd on Jul 20, 2023 20:52:28 GMT -5
First, I gotta say that looks AMAZING!! I love the pattern capture in that one! Great job on figuring that one out! Second...that shape (which is awesome!!) totally reminds me of those blow-up punching bags! Now, if I could just get the rock to bounce back up after it is knocked down, I would really have something. LOL Here's the best "bouncing rock" gif I could find! LOL  |
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