Re: [ATM] Snap, crackle, pop, this is the pits

["Chris Dalla Piazza" <dalchri@hotmail.com>]

I want to start off by saying thank you for all the advice, again.  The
whole reason I even chose to deal with this problem was because of my
success with building an Elgin back in December.  This forum is a fantastic
resource to be able to tap into so many experienced individuals that I'd
otherwise be unable to have contact with.  It's a great example of the good
the Internet can be.

The only reason I chose to attack this problem is that the Elgin eliminated
my TDE and raised center to produce a beautiful sphere.  So I decided to
temper the euphoria of that success with the renewed torture of dealing with
the pits I had noticed since starting polishing over again was no longer an
emotional investment.

I am using WAO.  I don't know if that implies a shape to the grains.  Last
night I managed to get lucky or maybe inobservant as I finished off one pair
of surfaces (this is a 6" Houghton) without more pits appearing.  Hopefully
the reverse pair will grant me luck as well.  For this reason, I am hesitant
to use the 5u WAO I have.  Next time I will probably try to find some grit
that is specifically spec'd as platelet shaped.

I am using city water and even worse, my house used to be on a well so all
the pipes have a coating of mud in them.  I think I will start using bottled
water, especially when I renew polishing.

I was using a grinding stone for beveling and yes, it does look like a mine
field next to the finished surface.

But even so, it still seems like the grains are coming from the grit.  I've
tried a few quick test wets without grit and there is no popping.  I never
get popping during a wet, only at the onset.  I've even been able to feel,
find, and remove the grains with my finger a few times.  By god back in the
220 SiC, I found a heart stopping chunk so big that the mirror and tool
wouldn't contact at all!  Also, I have noticed variation from grade to
grade.  The 25u had serious popping.  The 15u had none.  The 9u has minor
popping.  If I thought I could go straight to polishing from 15u I would.

On the other hand, I gather from your responses that none of you get this
snapping and popping from your grits.

The thing that I've been consoling myself with is that (hopefully) the
contamination is not hard since it grinds down quickly after one or two pops
and therefore can't do much damage.  It would be an interesting experiment
to throw a SiC grain in intentionally and find out how long it takes for the
thing to grind down.  I think I will leave that experiment to someone else!

What gives me the most hope from your replies is that some of you have
polished out pits.  Since polishing time is cheap now that is very
attractive.  I just wasn't expecting to enter polishing with pits.

Thank you again for all your input.  It's great to be able to talk these
ideas out!

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