I was right about the blackish stones, they are too soft. They are of the same material of one of the first stones I ground. They have some material that sparkles and flashes like pyrite. The thing is that material comes in square flakes that pull out on polishing. So what I was left with was a stone with a dull polish and all of its interesting sparkle gone. As you can see below, these stones still have their sparkle. On the smaller one the flakes are on edge and form a spiral to the center. The flakes are flat on the larger one and it gives flashes that I couldn't capture with the camera. The wet pic shows what they might look like if I had all the grits to polish soft stones.
I will do nothing further with the two soft stones as my daughter likes them as is. I asked her about the other four stones that I think are the same material and she'd like them ground to rough form. As she has me wrapped around her little finger, she'll get them as she wishes.
Main tasks on the 100 grit grinding step are -
- Grind near bezel to the top marks
- Grind from top marks to center dot
- Then with the use of the template, work the sides in so that it can tightly pass through the template
I was a bit lazy on the reddish stone in the middle. As I was sizing to template I found I was more than a bit off. This means I'll have more work to do on the 220 grit step to clean up the bezel.
The large quartz stone on the right has some major flaws that might cause problems with polishing. There are two major cleavage-like cracks that run across the width and length of the stone. There are also a number of flaws that reach the surface of the stone. This means that cavities can open up at each point where the surface is breached. In the wet picture you can tell that the flaws run deep and that there is no real chance to grind through them. Still, it is an interesting rock and I want to see how it turns out.
Next up, the 220 grit grind...
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220 grit grind --
Main tasks on the 220 grit grinding step are -
- Grind to bezel
- Get rid of any ridges/bumps near the bezel and any major ridges/bumps elsewhere on the stone
- Ensure that that the stone has been made as symmetrical as possible as it would be very hard to correct this in the sanding steps ahead
- Put a shallow 45 degree cut into the bottom edge to prevent chipping (just enough to remove the sharp edge)
- If the stone is very translucent or transparent, go over the bottom as well
Next I'll dop the stones and sand with 220 grit diamond....
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220 grit sanding --
The only task on the 220 grit sanding step is -
- Remove all ridges, bumps, and flat areas
Next I'll sand with 360 grit diamond....
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360 grit sanding --
Main tasks on the 360 grit sanding step are -
- Remove all ridges, bumps, and flat areas left from the 220 grit sanding
- Sand the whole stone to prepare for polishing
Irritating.
Next I'll sand with 600 grit diamond....
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600 grit sanding --
Main tasks on the 600 grit sanding step are -
- Remove all ridges, bumps, and flat areas left from the 360 grit sanding
- Sand the whole stone to prepare for polishing
On to the tripoli step....
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Polishing with tripoli --
Work towards the center as the pad dries. Continue to work as it starts to drag a bit. Be careful of letting it run too fast and hot or you'll get a weird flow effect.
Hmm, putting all this up tells me I need to work on my camera work considering I want to sell on ebay at some point.
