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Re: [ATM] Abrasives

> As my basement is too cold to polish anything, I have resumed another old
> project, My 12.5" f/6 telescope with a pre-generated curve. I just
> completed grinding with 320 Silicon Oxide. I have 500 SiO as well as 25
> micron AlO, any suggestions as to which I should use next?


Since both have about the same particle size, it can be confusing which to
select.

I always use the 500 SiO has the final carborundum before heading into
smoothing grinding with AlO.  320 is way too coarse as a final grit before
smoothing.  The odds of leaving subsurface fractures that cause trouble
during polishing are too high.

The 25 micron AlO will leave pits about 1/3 the size of the 500 carbo.  So
it's well worth your time to do both the 500 carbo and 25 micron aluminum
oxide.

Mel Bartels


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