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Here's a close-up of my grinding tool. It's just a
8" disk, with hexagonal tiles mounted on it. You can also see
the turntable that Tom Gorka sold while at the class. It was nice
to buy it, as I can concentrate on grinding at home, instead of worrying
about making one. Click picture to enlarge |
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Here's a close up of my 8" mirror. It's got a
spherical shape, now, but is still far from being a polished
surface. It has only been through 60 grit and 80 grit so far, so
it's got a texture similar to being sandpapered, only with pits instead
of long scratches. I have about 9+ hours of fine grinding left to
go, before I get to the polishing stages. Click
picture to enlarge |
| NOTES:
Overall, I found the class to be very exciting. Tom Gorka, Ken
Slater and Jay Drew were very helpful, and guided us well. Tom
also put an extra bit of sparkle in our smiles, by showing us how our
mirrors could already collect light into a point with a wet surface.
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| Post Class |
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Here is me working on grinding the mirror. It looks
like I'm really flying, but in reality, I'm only working at about one
complete cycle every 1-1.5 seconds.
Click image to enlarge. |
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Here's me grinding, but I paused for a moment, so that you
could see a little more detail.
Click image to enlarge. |
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It's important to keep checking the Sagitta, or depth, of
the spherical shape of the mirrror. Mine needs to stay right at
0.083" lower in the middle than at the sides.
Click image to enlarge. |
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Here's another more recent shot of the mirror. You'll
notice the black grid lines on the mirror. These are from my
'Sharpie Test'. The 'Sharpie Test' is where a grid is drawn with a
black Sharpie, and then you grind for a minute or two, to see whether
the mirror and tool are making good contact. If the grinding lines
are nice and even, then you have good 'contact' and therefore a sphere.
Click image to enlarge. |
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Here is a pic taken through a 10x eye loupe, like a jeweler
would use to check out jemstones. As you can see, there are some
bigger pits at the center of the pic. I tried to get rid of all
these pit marks, but they kept returning. Advice from Ken was that
it's likely that there is some larger grit in with the 120 grit, making
these pit marks.
Click image to enlarge. |
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Here's what the mirror should look like, taken through a
12x eye loupe. You'll
notice that the texture of this mirror pic is much more even.
Looks like I'm ready to leave 120 grit, and move to 220 grit.
Click image to enlarge. |