Re: ATM a couple fine grinding questions

[Diego Protas <dprotas@fi.uba.ar>]

At 16:41 21/12/98 -0800, you wrote: 
>
>   When i throw down more grit and water the grinding is easier and smoother
> for a few moments until the grit ends up in the channels between the tiles
> and then the resistance continuely increases until I can hardly move the
> mirror.  It gets easier again if i throw down more grit and water.  At this
> rate I'm going through an incredible amount of carbo.  


I had this same problem with my first tile tool. I filled the channels with
beeswax (not to the top,  maybe to reach 1/16 below the tile level) . When it
was time to advance to the next grit I peel off the wax (it will came out
easily, if not use hot water to soften it a little) and refilled the channels
again (with clean beeswax). When you reach the finer grits, this won't be
necessarily because the grit will stay on the tiles. My tool was portland
cement with vitrified ceramic (porcellanato in Argentina) tiles. 

>
> Also, after evaluating the progress that I've made I notices very, fine
> scratches over the surface of the mirror. They are difficult to see but 


The scratches are probably coming from the tiles grinding against the glass
without carbo (the heavy drag you noticed). If that is the reason, the filled
channels will provide the solution. Be sure to grind out the scratches
prior to
the next grit because then it will be harder. Also remember to bevel all your
tiles before you start grinding with 15 micron, at that time the borders will
be sharp and could cause many scratches (they did on mine :(  ).

Hope this helps!

Diego. 


==================
Diego  A. Protas
dprotas@fi.uba.ar
Buenos Aires - Argentina
58º 26' W  34º40' S  
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