From: "Dwight K. Elvey" 
To: atm{at}shore.net
Reply-To: "Dwight K. Elvey" 


Hi
 Clean and dry your tool. When done, glue some new tiles
over the old ones. Use boat epoxy to fill the voids so you don't have
trapped grit that can fall out later, at finer grits.
 Break in the new surface with 80 grit until at least +90%
of the tile surfaces are showing wear. Also, since you are adding thinkness
to the tool, it will have a longer ROC and should help a little in bringing
your mirror to a longer focal length.
 Use a salt shaker to add grit. Use small amounts of grit
and make sure it is spread evenly over the surface. Coarse grits are only
effect for the first 4 to 6 strokes. This means that they don't get much
chance to spread before they are no longer grinding. If you make a pile at
the center, that is where the grinding will happen, regardless of TOT or
MOT.
 After the 4 to 6 strokes, don't keep on stroking, it is
a waste of time. Add a little more grit. You can tell by the sound when the
grit has been broken down. Dwight


>From: "Jason Hissong" 
>
>Hi guys,
>
>Wow, I just subscribed to the list and 30 emails popped in already :)
>
>I am just starting out at ATM and I am working on a 6" F/8 mirror.  I
>got the initial curved worked out and I went from 80 grit to 120.
>However, I am finding that while I am going center over center
>alternating Mirror on top and tool on top, the curve got deeper.  It is
>now about F/5 (doh!)  I looked at my tool and the edges are pretty much
>gone (the tiles are worn down to the plaster surface).  I am wondering
>if the tool being worn down so much is grinding out the center now that
>there are not any edges?
>
>Anyways... now to correct it.  I think I need to make a new tool and
>maybe start over with 80 or even 60 grit to flatten it out again (tool
>on top, center over center).
>
>I am sure you guys get this question alot from us newbies..
>
>Thanks for the help!
>
>Jason Hissong
>
>
>

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