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Re: Correcting A Mirror Blank

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Posted by Robert May on June 19, 1998 13:50:20 UTC

On the problem of getting the backside (I gusess that is which side you are talking about) flat, just use some of the coarse grit to get it flatter. Remember that the process is just grinding. You can use a piece of iron or steel for the backside as a tool. I don't know what the shape is, but I might remind you that it is also possible to just put some pads on for where you are going to support the mirror in the cell. For a 9 point cell, fix only one of the triangles with a dent and make sure that the dent will allow for expansion without stress. For the actual grinding, I will suggest that you look about for the method of making a tile tool with plaster and some bathroom tiles (the little ones). If you are making a very short curve, you may need to make the tool again when the coarse grinding is done. Also, the backside can have dimples or peaks in it just so long as they aren't used for supporting the mirror when it is done. Good Luck and have fun Bob May

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