This blog is mainly about Telescope making, and some things about my politics. At last we finally have a President that can say "Fool me once; shame on you. Fool me twice; shame on me." instead of mixing up with an old Who song.

Sunday, July 13, 2008

No animals were harmed in the making of this mirror

I rewarded myself for having handily passed my first certification test by working out in my shed on my grinding tool today. Plenty more pictures. It rained like crazy today. Very odd for July in Georgia. On loud thunderbolt made the lights flicker and we lost a small branch out of one of our sweet gum trees. I normally collect rain water around here for garden irrigation (because of the 5 year drought) and I used some of it to fill my tub of water.

Anyway, David Harbours method of creating the grinding tool is a charmer. I slid it off the mirror friday evening after I got home without a hitch. Today I pulled out all of the match sticks, and the aluminum foil and wirebrushed any loose cement and picked at it with an awl. I finally bevelled the sharpest edges around the outside edge with the sharpening stone.

Unless you count insects, I didn't harm any animals. But man I hate wasps, and there are a couple of dead ones in my shed. And an ant that decided to crawl under my wirebrush. Oh well. Albert Schwitzer, I'm not.
In no particular order, some things I did or noticed with some comments. This is the edge after removing the dam. It has some puts that I will fill before coating with the water seal.

An edge-on view of how one row got a little skewed from the rest.

Edge on view of the smallest of the partial tiles. notice that they are a little slanted down to the left. Eventually they may come into contact maybe.

This is the right after removing the dam around the outside. you can see that I have removed some of the match sticks which were still wet. There were surprisingly few places where little "posts" of cement occurred at the intersection of match sticks. I guess its because I used square tiles instead of hex tiles like David did. Around the edge in the gaps are wadded up aluminum foil. If I were to do this again, I don't think I would use that, as the aluminum seems to have chemically reacted to the pOH of the concrete and got brittle, mushy, or flat out disintegrated. I had to scrap most of it out. I think I would try somthing non-porous, like silly putty or something.
Here is another shot of one of the chunks of foil.

Here it is with a third of the sticks removed.

And here I am using the awl to get the others. its really a matter of flicking them out of the way. Once that is done there were several places where cement extended down to the face of the tile. But there wasn't much of that, and a stiff wire brush got it all.

Like I said, it rained to beat the band. Here looking across my back yard. The camera was up under the brim of my hat.
I Thought I would rinse it off in the storm, but soon realized that all I was doing was getting grass on it. So I brought it back in and dipped a few gallons of water from my rain catching system into my wash tub. I stayed a little dryer that way too, heh!

This is how it looked right before rinsing it. I did the back of it too. It was a little mottled. the deepest indentation on the right is about 1/8 inch. Later I ground it over an old round concrete stepping stone. Smooth as err... concrete now :)

Here is one section of where I bevelled the edge.

Here is a little chip on one of the tiles. Hope it doesn't hurt much.

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